EP2691091A1

EP2691091A1 - Use of epigallocatechin gallate as an antiviral agent against infections by the hepatitis c virus

Info

Publication number: EP2691091A1
Application number: EP12711160.7A
Authority: EP
Inventors: Karin Seron; Jean Dubuisson; Yves Rouille; Czeslaw Wychowski
Original assignee: Centre National de la Recherche Scientifique CNRS; Institut Pasteur de Lille
Current assignee: Centre National de la Recherche Scientifique CNRS; Institut Pasteur de Lille
Priority date: 2011-03-28
Filing date: 2012-03-28
Publication date: 2014-02-05
Also published as: WO2012130893A1; JP2014510740A; US20140088184A1; FR2973249B1; CN103826626A; BR112013024904A2; FR2973249A1

Abstract

The present invention relates to a flavonoid compound of formula I, where R3, R5 and/or R7 is a group of formula II, or R1 and R2 are both OH groups, or to one of the pharmaceutically acceptable salts or esters thereof, for use as an antiviral agent in the treatment and/or prevention of a hepatitis C virus (HCV) infection. The invention also relates to an ex vivo method for reducing the infectivity of HCV or for inactivating HCV, including a step of contacting said hepatitis C virus with a compound of formula (I).

Description

Use of epigallocatechin gallate as antiviral agent against hepatitis C virus infections

The invention relates to a flavonoid compound or a pharmaceutically acceptable salt or ester thereof for use as an antiviral agent in the treatment and / or prevention of infection with the hepatitis C virus (HCV). The invention also relates to an in vitro inactivation method of HCV comprising a step of contacting said HCV with a flavonoid compound or a pharmaceutically acceptable salt or ester thereof.

Viral hepatitis C is a major cause of chronic liver disease that affects approximately 3% of the world's population. Infected patients are at high risk of cirrhosis or hepatocellular carcinoma requiring liver transplantation.

HCV is a linear positive-strand single-stranded RNA virus belonging to the family Flaviviridae in the genus Hepacivirus. This virus is the only known member of the Hepacivirus genus.

There are six major genotypes of HCV and more than 50 subtypes that are geographically distributed differently. As an indication, genotype 1 of HCV is predominant in Europe and the United States, genotype 4 in the Middle East and Africa. The high genetic heterogeneity of HCV linked to the high propensity of the virus to mutate has important clinical and diagnostic implications and may explain the difficulties in vaccine development and the lack of response to current treatments.

Indeed, standard treatments, namely, a combination of pegylated interferon (IFN) alpha (peginterferon alfa) and an antiviral drug such as ribavirin, are nonspecific and of moderate efficacy. Thus, a remission is observed in 40 to 80% of the cases of infected patients according to the viral genotype concerned, the genotype 1 being the most resistant to treatment. In addition to limited efficacy, this combination treatment has significant side effects. The most common side effects of IFN therapy are flu-like symptoms such as fever, muscle or joint pain or weight loss. In addition, neuropsychiatric side effects, including mood swings or psychoses of suicidal ideation are described. Pegylated interferon may also induce autoimmune diseases or may aggravate pre-existing autoimmune disorders. A common side effect with ribavirin is anemia, including hemolytic anemia, which requires continuous monitoring of blood parameters during the course of treatment.

These different side effects are a major reason for patients refusing this treatment. There is therefore a need for more effective, practical and better tolerated treatments.

A large majority of anti-HCV antivirals developed in the prior art are dependent on the viral genotype, or even the viral subtype. This is the case of viral metabolism inhibitors specific for proteases or viral polymerases. There is therefore also a need for inhibitors independent of the HCV viral genotype.

In order to solve these problems of the prior art, the inventors have shown that the flavonoids containing a 3,4,5-trihydroxy-phenyl group of formula

and more particularly some catechins, had a specific antiviral effect of HCV regardless of its viral genotype.

Flavonoid compounds are naturally present in plants and especially in most fruits and vegetables. They are responsible for the varied color of flowers and fruits and are an important source of antioxidants in the diet. They form a subclass of polyphenols. Many flavonoid compounds possess therapeutic virtues and are well known for their excellent potential for inhibiting the processes of angiogenesis and metastasis formation. Among the flavonoids and more particularly among the 3-hydroxyflavonoids, there are subclasses of flavonols, anthocyanins, leucoanthocyanins and catechins. Catechins are the most studied flavonoid compounds.

Catechins, their derivatives, even their degradation products, have multiple therapeutic properties. Their therapeutic effects are widely described in the form of an isolated catechin as in the form of extracts of green tea from which they are mainly derived. As an indication, catechin, (-) - epicatechin (EC); (-) - epigallocatechin (EGC), (-) - epicatechin-3-gallate (ECG) or epigallocatechin-3-gallate (EGCG). Thus catechins are described as having a preventive effect on obesity or on cardiovascular diseases such as atherosclerosis. They are also described as having an antioxidant, anticarcinogenic, antibacterial or antiviral effect (Khan N. et al., Life Sci., 200781, 19-33.). The modes of action of these catechins are diverse. Thus, their anti-carcinogenicity in the case of breast or prostate cancer, would be related to a cytotoxic effect of EGCG on cancer cells (Stuart EC.et al., Life Sci., 2006, 79: 2329-36 ). The antiviral effect of catechins would pass through different metabolic pathways. In the case of influenza or hepatitis B virus, EGCG and / or ECG would inhibit viral replication and / or transcription (Song JM et al., Antiviral Research 2005 68 66-74; et al., 2007). For influenza or human immunodeficiency virus type 1 (HIV-1), EGCG would inhibit binding to their respective host cells (Song JM et al., Antiviral Research 2005 68 66-74 and Nance CL. al., J Allergy Clin Immunol 2009 123: 459-65). In the case of Herpes Simplex Virus (type 1 and 2), EGCG would induce viral death by pore creation as a result of binding to envelope glycoproteins (Isaacs CE et al., Antimicrob Agents Chemother 2008 52: 962-70).

At the hepatic level, catechins are described as hepatoprotective especially because of their antioxidant nature. In addition, they are often associated with liver disease treatments. Thus, catechins are described in the treatment of viral hepatitis type B or C as reducing cell necrosis (Patrick L. et al., Altern Med Rev. 1999 Aug; 4 (4): 220-38.) . This effect is independent of the viral infection itself, but reduces the necrotic inflammation of the liver associated with it.

Catechins have been proposed for the treatment of diseases involving the immunosuppression route mediated by indoleamine 2,3-dioxygenase (IDO), among which certain cancers, but also viral infections including hepatitis C (WO 20081 15804). This treatment pathway is therefore nonspecific and indirect since it is an immunomodulation treatment.

The prior art also discloses treatment of hepatitis C by the use of an antiviral agent in admixture with a cell proteasome inhibitor. Among all the cell proteasome inhibitors mentioned, EGCG is found. The mechanism of action and advantage of a proteasome inhibitor in this treatment is, however, not described (WO201 1/009961).

Catechins are also mentioned in the treatment of hepatitis C in a polymeric form (US 2010/0055065). This polyphenol polymer is described as having antiviral activity by inhibiting the replication of HCV, provided that it contains at least 3 monomers. Many polyphenols are considered as potential monomers and more particularly all catechins. However, in this study, only the genotype 1b replicon as described by Lohmann et al. Science, 1999 is used by the authors.

Nevertheless, no document of the prior art describes a molecule having an HCV-specific antiviral effect that is both effective, having any or no side effects on the treated patient, and that is specific to HCV whatever the viral genotype. concerned.

In order to answer all the problems of the prior art, the invention relates to a compound of fo

in which :

• X is O when a is a single bond or 0 ⁺ when a is a double bond,

R1 and R2 are independently of one another a hydrogen atom, a hydroxyl group or a methoxyl group,

R3, R5 and R7 are, independently of one another, a hydrogen atom, a hydroxyl group (OH), an O-glycosyl group, a (C1 -C18) alkoxyl or a group of formula (II)

R4 and R6 are independently of each other, a hydrogen atom or an OH group,

• R4 'is a hydrogen atom or R4' is with R4 and the carbon atom to which they are linked, a group C = 0, when a is a single bond or R4 'is nothing when a is a double bond,

A and b identical or different being either a single bond or a double bond,

with the proviso that at least one of R 3, R 5 and R 7 is a group of formula (II) and / or R 1 and R 2 are both hydroxyl groups (OH), or a pharmaceutically acceptable salt or ester thereof, said compound of formula (I) being in the form of a pure stereoisomer or a mixture of enantiomers and / or diastereoisomers, including racemic mixtures, for use as an antiviral agent in the treatment and / or prevention of infection with the hepatitis C virus (HCV).

According to the compound of formula (I), a and b are either a single bond or a double bond and a and b are not simultaneously a double bond.

As used herein, the terms " pharmaceutically acceptable " and the grammatical variations thereof refer to compositions, carriers, diluents and reagents which are used interchangeably and can be administered to a mammal. without induction of undesirable physiological effects such as nausea, dizziness, gastric disturbances, etc.

The term "pharmaceutically acceptable salts or esters" refers to the relatively non-toxic, inorganic and organic acid addition salts, or esters of the compounds of the present invention, which are generally prepared by reaction of the free acid with a base organic or inorganic. These salts or esters can be prepared in situ during the final isolation and purification of the compounds. In particular, the acid addition salts can be prepared by separately reacting the purified compound in its purified form with an organic or inorganic acid and isolating the salt thus formed. Examples of acid addition salts are salts of hydrobromide, hydrochloride, sulfate, bisulfate, phosphate, nitrate, acetate, oxalate, valerate, oleate, palmitate, stearate, laurate, borate, benzoate, lactate, phosphate, tosylate, citrate, maleate, fumarate, succinate, tartrate, naphthylate, mesylate, glucoheptanate, lactobionate, sulfamates, malonates, salicylates, propionates, methylenebis-b-hydroxynaphthoates, gentisic acid, isethionates, di-p-toluoyltartrates, methanesulfonates, ethanesulfonates, benzenesulfonates, p -toluenesulfonates, cyclohexyl sulfamates and quinateslaurylsulfonate, and the like. (See, for example, S. M. Berge et al., "Pharmaceutical Salts" J. Pharm Sci, 66: p.1-19 (1977) which is incorporated herein by reference).

The compound according to the invention is a specific inhibitor of HCV in that within single-stranded RNA viruses, it inhibits a single member of the Flaviviridae family: HCV. Moreover, unlike many anti-HCV viral inhibitors, the compound according to the invention has an effective antiviral effect vis-à-vis all genotypes of HCV and even towards the genotypes most resistant to conventional antivirals. This is the case HCV genotype 1. This makes it an inhibitor of interest.

In addition, the inventors have shown that among the molecules of the flavonoid family, only the molecules having a 3,4,5-trihydroxy-phenyl group had an antiviral effect on HCV. Thus, the presence of the 3,4,5-trihydroxyphenyl group is essential for the antiviral activity of the compound of the invention. This structure is found in the galloyl group of formula (II) as well as in C2 of the central heterocycle (chromane heterocycle) when R1 and R2 are hydroxyl groups.

According to a first variant of the compound according to the invention, any one of the groups R 3, R 5 or R 7 is a group of formula (II), and the groups R 1 and R 2 are both OH groups.

According to a second variant of the compound according to the invention, at least two of the groups R 3, R 5 and R 7 are groups of formula (II).

The inventors have demonstrated an additive effect of the 3,4,5-trihydroxyphenyl groups on the antiviral nature of the compounds of formula (I), so that the antiviral effect of a compound of formula (I) comprising two 3,4,5-trihydroxy-phenyl groups is much greater than that of a compound having only one.

Advantageously, the compound according to the invention is a compound of formula (I) in which, the groups R 3, R 5 and R 7 are independently of each other, an O-alkyl group selected from the group consisting of an O-methyl group. , O-ethyl or O-propyl.

By "O-glycosyl group" is meant one or more carbon chains comprising at least one saccharide, namely a monosaccharide or an oligosaccharide bonded to an OH group of the compound of formula (I), the monosaccharide or the oligosaccharide being capable of be substituted by C1-C6 alkyl groups or by phenolic groups.

Typically the O-glycosyl moiety comprises at least one monosaccharide selected from the group consisting of glucose, galactose, rhamnose and arabinose. Preferably, the glycosyl moiety is selected from the group consisting of a monosaccharide, a disaccharide or a tri-saccharide.

Advantageously, the compound according to the invention is aglycan. the invention also relates to a compound of formula (I) in which,

• X is O when a is a single bond or 0+ when a is a double bond, a and b identical or different being either a single bond or a double bond,

The groups R1, R5 and R7 are hydroxyl groups,

R2 is a hydroxyl group or a hydrogen atom,

R 3 is a hydroxyl group, a hydrogen atom or a galloyl group of formula (II)

• R4 'is a hydrogen atom when a is a single bond or R4' is nothing when a is a double bond, and

• R6 is a hydrogen atom

or a pharmaceutically acceptable salt or ester thereof.

According to a first variant, the compound according to the invention is a compound of formula

in which :

R3, R5 and R7 are, independently of one another, a hydrogen atom, an OH group, an O-glycosyl group, a (C1 -C18) alkoxyl or a group of formula (II)

both OH groups,

or a pharmaceutically acceptable salt or ester thereof.

Preferably, the compound is an anthocyanidin or an anthocyanin. Typically, the compound according to the invention is a compound of formula (III) in which R1, R2, R3, R5 and R7 are OH groups and R6 is a hydrogen atom. One such compound of formula (III) is delphinidin (3,3 ', 4', 5,5 ', 7-Hexahydroxyflavyliumchloride CAS No. 528-53-0). Delphinidin can be modified by glycosylation on R3, R5 and / or R7 groups. Delphinidin may be in the form of a salt, such as delphinidine chloride.

Typically, the compound according to the invention is the compound of formula (III) in which R1, R2, R5 and R7 are OH groups and R3 and R6 are hydrogen atoms. Such a compound of formula (III) is tricetinidine (3 ', 4', 5,5 ', 7-pentahydroxyflavylium chloride, CAS No. 65618-21-5). Tricetinidine can be modified by glycosylation on R3, R5 or R7 groups. Tricetinidine is found in tea and is the degradation product by oxidative degassing of EGCG.

Typically, the compound according to the invention is the compound of formula (III) in which R1, R2, R3 and R7 are OH groups; R6 is a hydrogen atom, R5 is an O-methyl group. One such compound of formula (III) is Pulchelidine (3,7,3 ', 4', 5'-Pentahydroxy-5-methoxyflavylium, CAS RN 19077-86-2.) Pulchelidine may be modified by glycosylation on R3 groups. and R7.

Delphinidine Tricetinidine Pulchelidine According to a second variant, the compound according to the invention is a compound of formula

(IV)

in which :

R 3 is an OH group, an O-glycosyl group, a (C 1 -C 18) alkoxyl or a group of formula (II)

R5 and R7 are, independently of one another, a hydrogen atom, an OH group, an O-glycosyl group, a (C1 -C18) alkoxyl or a group of formula (II),

R 6 is a hydrogen atom or an OH group, and

at least one of R3, R5 or R7 is a group of formula (II), or R1 and R2 are both OH groups,

or a pharmaceutically acceptable salt or ester thereof.

Preferably, the compound according to the invention is a flavonol (3-hydroxy-2-phenylchromen-4-one).

Typically, the compound according to the invention is the compound of formula (IV) in which R1, R2, R3, R5 and R7 are OH groups; R6 is a hydrogen atom. One such compound of formula (IV) is Myricetin (or 3,3 ', 4', 5 ', 5,7-hexahydroxy-2-phenylchromen-4-one; CAS529-44-2). Myricetin can be modified by glycoylation especially on the R3 group.

myricetin

According to a third variant, the compound according to the invention is a compound of formula

in which :

R 5 and R 7 are, independently of one another, a hydrogen atom, an OH group, an O-glycosyl group, a (C 1 -C 18) alkoxyl or a group of formula (II), and

or a pharmaceutically acceptable salt or ester thereof.

Preferably, the compound according to the invention is a flavan-3-ol (flavanol or catechin).

Catechins are a subfamily of flavonoids whose structure is based on 2-phenyl-3-chromano.

Typically, the compound according to the invention is the compound of formula (V) in wherein R1, R2, R3, R5 and R7 are OH groups, the compound according to the invention is referred to as (-) - Epigallocatechin (EGC)

((2R, 3R) -2- (3,4,5-trihydroxyphenyl) chroman-3,5,7-triol, CAS No. 970-74-1) when the C2 and C3 groups of the central heterocycle (heterocycle chromane) are in cis and referred to as (-) - Gallocatechin

(2H-1-Benzopyran-3,5,7-triol, 3,4-dihydro-2- (3,4,5-trihydroxyphenyl) - (2S, 3R) CAS number 3371 -27-5) or ( (+) - Gallocatechin (GC)

(2H-1-Benzopyran-3,5,7-triol, 3,4-dihydro-2- (3,4,5-trihydroxyphenyl) -, (2R.3S), CAS No. 970-73-0) when the C2 and C3 groups of the central heterocycle (heterocycle chromane) are in trans.

Typically, the compound according to the invention is the compound of formula (V) in which R 1, R 5 and R 7 are OH groups; R2 is a hydrogen atom; R 3 is a galloyl group of formula (II), the compound according to the invention being referred to as (-) - Epicatechin-3-gallate (ECG) ((2R, 3R) -2- (3,4-dihydroxyphenyl) -3, 4-Dihydro-1 (2H) -benzopyran-3,5,7-triol

3- (3,4,5-trihydroxybenzoate); CAS RN 1257-08-5) when the C2 and C3 groups of the central heterocycle (heterocycle chromane) are in cis and called catechin-3-gallate (CG) ((2S, 3R) -2- (3 , 4-Dihydroxyphenyl) -3,4-dihydro-1 (2H) -benzopyran-3,5,7-triol 3- (3,4,5-trihydroxybenzoate) CAS No. 130405-40-2) when the groups C2 and C3 of the central heterocycle (heterocycle chromane) are in trans.

Typically, the compound according to the invention is the compound of formula (V) in which R1, R2, R5 and R7 are OH groups; R3 is a galloyl group of formula (II), the compound according to the invention being named (-) - Epigallocatechin-3-Gallate (EGCG) ((2R, 3R) -5,7-dihydroxy-2- (3,4) , 5-trihydroxyphenyl) -3,4-dihydro-2H-chromen-3-yl 3,4,5-trihydroxybenzoate, CAS No. 989-51 -5) when the C2 and C3 groups of the central heterocycle (heterocycle chromane) are in cis and named (-) - Gallocatechin gallate (GCG) ((2S, 3R) -2- (3,4,5-Trihydroxyphenyl) -3,4-dihydro-1 (2H) -benzopyran-3 , 5,7-triol 3- (3,4,5-trihydroxybenzoate), CAS RN 4233-96-9) when the C2 and C3 groups of the central heterocycle (heterocycle chroman) are in trans.

(+) - gallocatechin-3-gallate (GCG) (-) - epigallocatechin-3-gallate (EGCG)

Preferably, the compound according to the invention is selected from the group consisting of delphinidin, Myricetin, tricetinidine, Pulchelidine, epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), catechin gallate (CG), gallocatechin gallate (GCG), epicatechin gallate (ECG), their pharmaceutically acceptable salts and esters, and mixtures thereof.

Advantageously, said compound according to the invention is selected from the group consisting of epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), catechin gallate (CG), gallocatechin gallate (GCG ), epicatechin gallate (ECG), pharmaceutically acceptable salts and esters thereof, and mixtures thereof.

Preferentially, said compound according to the invention is epigallocatechin gallate (EGCG) or a pharmaceutically acceptable salt or ester thereof.

The flavonoid compounds according to the invention being naturally present in plants and in particular in most fruits and vegetables, they can be obtained by purification. For example, catechins may be obtained by extraction of green or black tea by various filtration methods, such as those described in US Pat. No. 6,383,392 or EP 1 077 211. The anthocyanins can also be obtained by purification from plants as described in the state of the art and in particular in the patent applications US 2010041877 or US 2003147980. Such flavonoid compounds are found in commerce.

The flavonoid compounds can also be obtained by chemical synthesis by the implementation of methods known to those skilled in the art such as in particular solid phase synthesis processes. Such flavonoid compounds are commercially available.

In the context of the present invention, the expression "hepatitis C virus" or "HCV" must be understood as referring to all the genotypes of the hepatitis C virus, genotypes already described or not described, in particular genotypes numbered from 1 to 6, as well as their different subtypes, more particularly genotypes 1a, 1b, 2a, 2b, 3, 4, 5, and 6. This expression must also be understood as a reference a recombinant or non-recombinant HCV virus capable of infecting a host, such as a target cell of a subject. "Target cell (s)" or "target cell (s) of HCV", "host cell (s)" or "host cell (s) of HCV" means cells likely to be infected with HCV. The host cell or target cell according to the present invention is the hepatocyte.

The term "antiviral agent" is used in reference to an agent that is capable of interacting directly with HCV or with one or more of its constituents and induces inhibition of HCV infection by either a decrease or abolition of HCV infection. viral entry, viral replication or pathogenesis or any other event occurring in the host cell or their combinations. This direct action of the antiviral agent is to oppose the indirect action of compounds used in the treatment of HCV infections and acting by stimulation of the immune system for example.

The term "HCV infection" or "viral infection" in reference to HCV refers to the condition of a subject or patient infected with HCV. HCV infection refers to either asymptomatic or chronic HCV infection, regardless of stage of development. This expression also refers to the entry, replication, or other event or process involved in the pathogenesis of HCV in a host cell. Thus, the infection comprises the introduction of an infectious agent, such as a recombinant or non-recombinant HCV virus, capable of infecting a host, such as a cell of a subject.

The term "prevention" as used herein with reference to HCV infection refers to reducing the risk or inhibiting the development of a viral infection. The compound of the invention inhibiting the early stages of infection is particularly advantageous in the prevention of HCV infection.

The term "treatment" as used herein generally refers to the improvement of a sign or symptom of a disease or condition related, for example, to a particular HCV infection. because of the inhibition of the virus, the stop of its development, the decrease of the viral load of the patient or the eradication of the virus. Thus, reference is made to means for regression, reduction, inhibition of HCV progression, or prevention of HCV infection or one or more symptoms of this infection.

Said compound according to the invention is an antiviral agent in particular, by inhibition of the infection of a target cell (such as a hepatocyte cell) with the hepatitis C virus and / or the transmission of the virus of the hepatitis C virus. hepatitis C between two target cells. For example, from an infected hepatocyte cell to an uninfected hepatocyte cell.

The compound according to the invention inhibits the two major modes of viral infection, namely, the infection of a healthy target cell (such as an uninfected hepatocyte cell) with the isolated virus and the second mode, viral dissemination. from cell to cell, that is, infection by an infected target cell of a non-infected target cell. This latter mode of transmission is important since it is suspected to be a dominant pathway in vivo for some families of enveloped viruses.

Preferably, said compound is an antiviral agent by inhibiting the entry of the hepatitis C virus. The use of an entry inhibitor may be particularly advantageous in the case of a liver transplantation in order to avoid the transplanted liver infection. The inventors have demonstrated such an inhibition, by the use of a reference study model allowing the expression of glycoproteins of the viral envelope of interest that it is the infectious viral pseudoparticles. Thus, according to the invention, the expression "inhibition of viral entry" or "inhibition of the entry of the virus" must be understood as inhibition of the passage of a viral genome from the outside to the inside. of the host cell, whether it is an infection mediated by an individualized virus particle or any other mechanism leading to infection of a non-infected host cell. This expression can also be understood as the inhibition of any of the steps of viral infection prior to the release of the viral genome into the cytoplasm of the host cell. These preliminary steps are: i) the adhesion or attachment of the virus or an infected host cell to the surface of a second host cell (typically an uninfected host cell), ii) the interaction with the (s) ) viral specific receptor (s) and iii) the fusion of the viral lipid envelope, the viral particle with a cell membrane (plasma or endosomal) allowing the introduction of the viral genome into the cytoplasm of the infected cell. The inventors have carried out experiments aimed at splitting the mechanism of the entry of HCV into the host cell in its 3 constituent steps and have thus shown that only the attachment step is inhibited by the compounds of formula (I) such that EGCG, ECG, EGC or Delphinidine. The attachment stage is the earliest stage of the viral entry mechanism. Such results can be supported by "binding" experiments and quantification by quantitative RT-PCR of the virus RNA attached to the cell or quantification of the capsid protein.

Preferably, said compound is an antiviral agent by inhibiting HCV surface glycoproteins in their function during the steps of entry of the viral genome into the uninfected host cell. This can be confirmed by pull down or microcalorimetry tests and surface plasmon resonance (Biacore).

Advantageously, the compound according to the invention is an antiviral agent by inhibiting the adhesion of the hepatitis C virus, or of a host cell infected with the hepatitis C virus, to the membrane of a host cell uninfected.

Preferably, said compound is an antiviral agent by inhibiting the interaction of HCV surface glycoproteins with at least one target protein of a host cell and more particularly the inhibition of HCV glycoproteins such as E1 and / or E2 glycoproteins. , and in particular, of the E1 protein (Acc No: AAB67037 SEQ ID NO: 1) or the E2 protein (Acc No: AAB67037 SEQ ID NO: 2) of HCV genotype 1a, of the E1 protein (Acc No AY734976 SEQ ID NO: 3) or E2 protein (Acc No: AY734976 SEQ ID NO: 4) of genotype 1b HCV, E1 protein (Acc No: AB047639 SEQ ID NO: 5) or E2 protein (Acc No: AB047639 SEQ ID NO: 6) HCV genotype 2a, E1 protein (Acc No: AY734982 SEQ ID NO: 7) or E2 protein (Acc No: AY734982 SEQ ID NO: 8) HCV genotype 2b, protein E1 (Acc No: AY734984 SEQ ID NO: 9) or the E2 protein (Acc No: AY734984 SEQ ID NO: 10) of genotype 3a HCV, of the E1 protein (Acc No: AY734986 SEQ ID NO: 1 1) or of the E2 protein (Acc No: AY734986 SEQ ID NO: 12) HCV genotype 4, E1 protein (Acc No: AY785283 SEQ ID NO: 13) or E2 protein (Acc No: AY785283 SEQ ID NO: 14) HCV genotype 5, protein E1 ( Acc No: AY736194 SEQ ID NO: 15) or E2 protein (Acc No: AY736194 SEQ ID NO: 16) of HCV genotype 6.

By "inhibition of the interaction of HCV surface glycoproteins" or "inhibition of the binding of HCV surface glycoproteins" or "inhibition of the interaction of glycoproteins E1 and / or E2" is meant the inhibition of the specific binding of at least one of the surface glycoproteins of HCV and in particular one of the glycoproteins E1 or E2 with at least one target protein or glycoprotein of a host cell. For example, inhibition of binding between E1 and / or E2 glycoproteins and glycosaminoglycans of hepatocytes. HCV surface glycoproteins can be found on the surface of a virus particle but can also be attached to the surface of an infected target cell. Binding of the surface glycoproteins of HCV and in particular glycoproteins E1 and / or E2 to the target proteins is carried out during the step of attachment or adhesion of HCV with a target cell, or the step of attachment or adhesion of an infected target cell to another target cell.

In the context of the present invention, the "target proteins" or "target proteins of a host cell" are the surface proteins or glycoproteins, namely transmembrane proteins or glycoproteins anchored to the surface of the plasma membrane of host cells. , which proteins are specifically recognized by the surface glycoproteins of HCV and in particular by glycoproteins E1 and / or E2. By way of examples, mention may be made of the glycosaminoglycans of a target cell such as a hepatocyte.

Thus, the inventors have demonstrated that inhibition by compounds of formula (I) such as EGCG, ECG, EGC or Delphinidine specifically involves glycoproteins E1 and / or E2. The compounds of the invention would inhibit the interaction between HCV E1 and / or E2 proteins and target proteins such as hepatocyte glycosaminoglycans. In addition, the inventors have demonstrated that the inhibitory effect of the viral entry mediated by the compounds of formula (I) such as EGCG, ECG, EGC or Delphinidine, directly implicates the glycoproteins of the viral envelope at a conserved area of them. Indeed, the inventors have shown that the inhibitory effect of the compounds of formula (I) such as EGCG, ECG, EGC or delphinidin was observed on all the HCV viral genotypes namely the genotypes 1a, 1b, 2a, 2b, 3, 4, 5, and 6 indicating that the binding of the molecules according to the invention with glycoproteins E1 and / or E2 takes place in a very conserved zone of the latter .

According to the invention, the treatment and / or prevention of infection with the hepatitis C virus is intended for a patient resistant or intolerant to the treatment of an infection with HCV, an immunomodulatory agent and / or by an inhibitor of viral metabolism.

HCV genotype 1 is the most refractory to current treatments. He is said to be responsible for 70% of known cases of hepatitis C in the United States, Japan and Western Europe. However, less than 50% of patients obtain a sustained virological response with the current treatment. The compound according to the invention allows the inhibition of the HCV infection of all the described genotypes and more particularly HCV genotype 1 for which it shows a very strong antiviral capacity.

"Viral Inhibitors" can be defined in three groups.

The first includes inhibitors of viral metabolism. By "inhibitors of viral metabolism" is meant: i) translation inhibitors including inhibitors of TIRES (Internai Ribosome Entry Site), ribozymes or SiRNA; ii) protein processing inhibitors such as protease inhibitors (NS3 / NS4a proteases), iii) inhibitors of viral genome replication including inhibitors of the binding between viral RNA and RNA polymerase or inhibitors NS5B polymerase that may be nucleoside or non-nucleoside inhibitors or helicase inhibitors; vi) inhibitors of viral assembly such as glycosylation inhibitors.

The second group of inhibitors includes the "inhibitors of viral entry" in the hepatocyte. In particular, any molecule capable of partially or completely inhibiting the step of recognizing the host cell by an individualized viral particle, or by the membrane of an infected host cell or the step of attachment of the virus or the membrane of an infected host cell, on the cell surface of the uninfected host cell or the endocytosis stage of the viral particles by the host cell or the fusion step of the viral membrane with the endosomal membrane.

The third includes "immunomodulatory agents". By "immunomodulatory agents" is meant molecules of synthetic or natural origin which make it possible to initiate or potentiate the immune response of mammals during of a viral infection. Examples of immunomodulatory agents that may be mentioned include interferons type 1 (such as interferons alpha (IFN-α), beta (IFN-β) or omega (IFN-ω)), interferons type 2 (such as interferon gamma IFN-γ) and pegylated interferons.

According to a first preferred embodiment, the compound according to the invention is co-administered with an additional agent for treating and / or preventing an infection with HCV. Said additional agent is preferably a viral inhibitor as defined above.

The use of such a combination of several inhibitors makes it possible to reduce the risks of viral resistance often observed in the context of treatments for viruses with a high mutation rate.

Advantageously, the additional agent is an immunomodulatory agent or an inhibitor of the viral metabolism of HCV.

According to a second preferred embodiment, said compound is the only antiviral agent administered for the treatment and / or prevention of infection with the hepatitis C virus.

Advantageously, said compound is formulated in the form of a pharmaceutical composition. Typically, said pharmaceutical composition contains a pharmaceutically acceptable vehicle and the compound according to the invention.

By "pharmaceutically acceptable carrier" is meant any solvent, dispersion medium, retarding agent, etc., which does not produce a side reaction, for example allergic, in humans or animals. The pharmaceutically acceptable carriers are well known to those skilled in the art, and include those described in

"Remington's Pharmaceutical Sciences" (Mack Publishing Company, Easton, USA, 1985).

The pharmaceutically acceptable vehicle is in particular chosen according to the route of administration, which may for example be oral, sub-lingual, nasal, oral, transdermal, intravenous, subcutaneous, intramuscular and / or rectal. The dose depends on factors such as the active principle considered, the mode of administration, the therapeutic indication, the age, the weight and the state of the patient.

The invention also relates to a method of treating or preventing an HCV infection, comprising administering to an individual in need of a therapeutically effective amount of a compound of formula (I) pharmaceutically acceptable salts and esters thereof or mixtures thereof, said compound of formula (I) being in the form of a pure stereoisomer or in the form of a mixture of enantiomers and / or diastereoisomers, including racemic mixtures, preferentially, said compound of Formula (I) is selected from the group consisting of delphinidin, Myricetin, tricetinidine, Pulchelidine, epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), catechin gallate (CG) gallocatechin gallate (GCG), epicatechin gallate (ECG), their pharmaceutically acceptable salts and esters, and mixtures thereof. The individual is preferably a mammal, more particularly a human. The effective therapeutic dose can easily be determined by those skilled in the art.

The term "therapeutically effective amount" or "effective therapeutic dose" as used herein means the amount of antiviral agents such as flavonoid compounds of formula (I) or their derivatives causing a biological or medical response in a tissue, system animal or human biologic that includes the relief of symptoms of HCV infection including inhibition of the virus, stopping its development, decreasing the viral load of the patient or the eradication of the virus. For the purpose of prevention, a therapeutically effective amount may also be considered a "prophylactic amount" of active agents.

The terms "patient" or "patient in need" are intended for a human or non-human mammal that is affected or likely to be affected by HCV. In a preferred embodiment, the patient is a human being. In another embodiment, the patient is a chimpanzee.

The subject of the invention also relates to a preferentially ex vivo method of reducing the infectivity or inactivation of a hepatitis C virus (HCV) comprising a step of contacting said hepatitis virus C with a compound of formula (I):

in which :

• X is O when a is a single bond or 0 ⁺ when a is a double bond,

• R3, R5 and R7 are independently of each other, a hydrogen atom, an OH group, an O-glycosyl group, a (C 1 -C 18) alkoxyl or a group of formula (II):

R4 and R6 are independently of each other, a hydrogen atom or an OH group,

A and b identical or different being either a single bond or a double bond,

with the proviso that at least one of R3, R5 and R7 is a group of formula (II) and / or R1 and R2 are both OH groups,

or a pharmaceutically acceptable salt or ester thereof, said compound of formula (I) being in the form of pure stereoisomer or as a mixture of enantiomers and / or diastereoisomers, including racemic mixtures.

HCV is contacted with the compound of formula (I) for a time and under conditions sufficient to achieve inactivation or inhibition of partial or complete virus. According to the invention, the HCV is brought into contact with the compound of formula (I) before or during the infection step. The infection step is the step of bringing the virus into contact with its target cell (s).

By "infectiousness" is meant the infectious nature of the virus, namely the capacity of the virus to cause a viral infection within the meaning of the present invention, in particular the reduction of the capacity of the virus to enter a target cell preferentially, the reduction of its ability to attach to a target cell.

Advantageously, the ex vivo method according to the invention can be implemented by bringing into contact a sample capable of comprising a HCV and a compound of formula (I) in a liquid or semi-liquid medium, the compound of formula (I) being preferentially applied at a concentration of 0.5 to 100 μl, advantageously at a concentration of 10 to 80 μΜ or even 20 to 70 μΜ. Typically, the compound of formula (I) is applied at a concentration of 50 μΜ. The method can be carried out at a temperature of 4 to 37 ° C, preferably 4 to 10 ° C or 20 to 37 ° C. The compound according to the invention can be brought into contact with said virus for 15 to 90 minutes, preferably 30 to 45 minutes.

Preferably, according to the ex vivo method of reducing infectivity or inactivating HCV, said hepatitis C virus is present in a biological sample.

The term "biological sample" refers to a sample of biological origin or taken from a biological organism such as an organ, a tissue, a cell, a population of cells, a biological fluid, a protein or a purified peptide. Non-limiting examples include liquid samples of biological origin such as blood, plasma, serum, cerebrospinal fluid, lymph or cell lysates; solid samples such as organs intended especially for transplantation or tissues or cell cultures that may be intended for transplantation.

According to an advantageous variant, the ex vivo method of reducing the infectivity or inactivation of HCV according to the invention comprises an additional step of washing the biological sample. This step allows the reduction or elimination of the compound of formula (I) of said biological sample. The washing step may be preceded by a step of incubating the compound mixture of formula (I) in said biological sample.

The ex vivo method according to the invention may also comprise an additional step of controlling the infectivity of a biological sample. Such a step may be considered before the step of contacting the compound of formula (I) with the biological sample or after contacting; to determine if another cycle of contacting the biological sample with the compound of formula (I) is to be considered. Such a control step can be carried out by any means allowing in particular, a rapid detection of an infection with HCV. Thus, a detection of a specific marker of HCV can be carried out, for example by the use of an antibody specific for a viral protein or by a PCR detection of the HCV RNA.

DESCRIPTION OF THE FIGURES

Figure 1: Illustration of the relative viral infection of Huh7 cells by the JFH1 -RLuc virus as a function of the presence of (+) - catechin (C), (-) - epicatechin (EC), (-) - epicatechin-3 -gallate (ECG), (-) - epigallocatechin (EGC) and (-) - epigallocatechin-3-gallate marketed by EXTRASYNTHESE® (EGCG EXTRASYNTHESE®) or by CALBIOCHEM® (CALBIOCHEM® EGCG) at 50μΜ or DMSO. Figure 2: Illustration of the relative viral infection of Huh-7 cells by the JFHI -RLuc virus as a function of the concentration of the medium in EGCG (0, 0.5, 5, 50 μΜ) during infection or pretreatment of 50 μC of EGCG virus before the infection stage.

Figure 3: Illustration of the relative viral infection of Huh-7 cells infected with infectious viral pseudoparticles (VHCpp) expressing on their surface the envelope proteins E1 and E2 of the HCV virus genotypes 1a, 1b, 2a, 2b , 3, 4, 5, or 6 or infected with VSV pseudoparticles expressing VSV envelope protein (VSVpp) depending on the presence of EGCG (50 μΜ) or DMSO in the infection medium.

Figure 4: Illustration of the relative viral infection of Huh-7 cells infected with yellow fever virus (YFV) or Sindbis virus (SINV) or MDBK cells infected with bovine diarrhea virus (BVDV) as a function of the presence of EGCG (50 μl) or DMSO in the medium of infection.

FIG. 5: Illustration of the number of cells per infectious focus of the viral infection of Huh-7 cells by the JFH1 virus, with or without EGCG (at 50 μM).

Figure 6: Illustration of the percentage of cells infected by the cell supernatants at the P0 to P4 passages depending on whether the infection medium was treated with DMSO or EGCG.

Figure 7: Figure 7 A. Diagram illustrating the experimental conditions for the study of the inhibitory effect of EGCG on the entry of HCV (sample 5) and more particularly on the attachment steps (sample 2), d interaction with host cell receptors (sample 3) and the endocytosis and fusion stage of viral and cell membranes (sample 4), with DMSO being used as a control (sample 1).

Figure 7B. Illustration of the relative viral infection of Huh7 cells by JFH1 -RLuc virus according to the presence of DMSO or EGCG (at 50 μΜ) in samples 1 to 5.

Figure 8: Illustration of the relative viral infection of Huh7 cells by the HCVVV virus as a function of the presence of EGCG or delphinidin (at increasing concentrations). This graph shows a representative experience of 3 independently performed experiments.

Figure 9: Illustration of the relative viral attachment of Huh7 cells by the HCVV virus according to the presence of DMSO, 50 μΜ of EGCG, 50 μl of delphinidine chloride or 500 g of heparin. relative attachment is expressed as a percentage of the control (DMSO) for which a value of 100% has been arbitrarily assigned. EXAMPLES

Materials and methods

Reagents.

Dulbecco's Modified Medium's DMG Medium (GIBCO®), Dulbecco's Essential Minimum Medium (GIBCO®), phosphate buffered saline (PBS), reduced serum (OptiMEM® from GIBCO®), L-alanyl-L-glutamine (GLUTAMAX-I ™), goat serum, horse serum, and fetal calf serum (FCS) are products marketed by Invitrogen. 4 ', 6-Diamidino-2-phenylindole (DAPI) was obtained from MOLECULAR PROBES®. (-) - Epigallocatechine Gallate (EGCG CALBIOCHEM®) and polyvinyl alcohol (MOWIOL® 3-88) are marketed by CALBIOCHEM®. The ExGen500® in vivo transfection reagent is marketed by EUROMEDEX®. (-) - catechin, (-) - epicatechin, (-) - epicatechin - 3 - gallate (ECG), (-) - epigallocatechin (EGC), and (-) - epigallocatechin - 3 - gallate ( EGCG Extrasynthesis®) are sold by Extrasynthèse® (Lyon, France). Delphinidin chloride is produced by Extrasynthesis (Lyon, France). The other reagents were marketed by SIGMA®.

Antibody.

The mouse monoclonal antibodies (MAb) directed against the proteins of the envelope (E) of the yellow fever virus (YFV) referenced MAb 2D12 (ATCC CRL-1689) and the mouse monoclonal antibodies directed against the NS3 protein of the virus bovine viral diarrhea (anti-BVDV) referenced NS3 MAb Osc-23 (Boulanger, D., et al., J. Gen. Virol., 1991. 7: pp. 1195-1198) were produced in vitro using the MiniPerm® device (HERAEUS®) according to the manufacturer's recommendations. The anti-CD81 mouse monoclonal antibodies referenced MAb 5A6 (Oren, R., et al., Mol Cell Biol, 1990. 10 (8): 4007-15) were kindly provided by S. Levy (Stanford University). and the anti-CD81 monoclonal antibodies (referenced MAb JS-81) are marketed by BD Pharmingen®. IgG conjugated goat anti-mouse IgG antibodies are marketed by MOLECULAR PROBES®.

Cell lines and cell culture conditions

The Huh-7 hepatic cell line (Nakabayashi, H. et al., Cancer Res, 1982. 42 (9) p3858-63) as well as HEK 293T cells were cultured in DMEM medium (Invitrogen®) supplemented with L-alanyl-L-glutamine (GLUTAMAX-I ™) and 10% fetal calf serum. Bovine kidney cells of Madin-Darby (Madin-Darby Bovine Kidney MDBK) were cultured in DMEM supplemented with L-alanyl-L-glutamine (GLUTAMAX-I ™) supplemented with 10% horse serum. The BHK-21 cells were cultured in MEM medium (Invitrogen®) supplemented with L-alanyl-L-glutamine (GLUTAMAX-I ™) and 10% fetal calf serum.

VHCcc.

The modified version of the plasmid encoding the genome of JFH1 isolate (genotype 2a; GenBank accession number AB237837) was kindly provided by MT Wakita (National Institute of Infectious Diseases, Tokyo, Japan) (Wakita, T., and al., Nat Med, 2005. 11 (7): 791-6.). The modified JFH1 viral clone contains mutations leading to the following amino acid changes F172C, P173S and N534K that have been shown to induce an increase in viral load (Deigrange, D., et al., J Gen Virol, 2007. 88 (Pt 9): pp. 2495-503.). In addition, the E1 sequence encoding residues 196TSSSYMVTNDC was modified to reconstitute the A4 epitope (SSGLYHVTNDC) of the HCV glycoprotein E1 (Dubuisson, J., et al., J. Virol, 1994. 68 (10): pp. 6147-60.) as described in the state of the art (Goueslain, L., et al., J. Virol, 2010. 84 (2): 773-87). The JFH-Luc plasmid contains the Renilla reniformis luciferase gene (RLuc) as a reporter gene and the JFH-ΔΕΙ E2-Luc plasmid contains a deletion that does not cause a reading shift in the E1 E2 region (Wakita, T., et al., Nat Med, 2005. 11 (7): 791-6), as described in the prior art (Goueslain, L., et al., J. Virol, 2010. 84 (2)). : pp. 773-87 and Rocha-Perugini, V., et al., PLoS ONE, 2008. 3 (4): pp. e1866).

In order to generate HCV genomic RNA, the plasmids are linearized at the 3 'end of the HCV cDNA by cleavage at the XbaI restriction site. Following the Mungo bean nuclease treatment, the linear DNA is then used as a template for in vitro transcription with the MEGAscript® kit marketed by AMBION®. RNA transcribed in vitro is transfected by electroporation into Huh-7 cells as described in the prior art (Kato, T., et al., Gastroenterology, 2003. 125 (6): 1808-17). The viral extracts were obtained as described in the prior art (Deigrange, D., et al., J Gen Virol, 2007. 88 (Pt 9): pp. 2495-503).

Regarding HCV virus infection assays, Huh-7 cells are in culture in 24-well plates, in which the infection is carried out for 2 hours at 37 ° C. For EGCG assays, the viruses are preincubated in the presence of EGCG for 45 min before infection and / or EGCG is added during infection with the culture medium until the end of the reaction, unless otherwise stated. In some trials, EGCG is added after the infection stage for various times (24, 48 or 72 hours post-infection). The infection rate is evaluated by measuring the luciferase activity 48 hours after the infection stage in the cell lysates, by the use of the Renilla luciferase assay System kit marketed by PROMEGA® or by immunofluorescence with the anti-antibodies. -E1 (A4) at 48 hours or 72 hours after infection.

VHCDD.

Pseudotyped retroviral particles have been described by the prior art (Bartosch, B., Dubuisson, J., and FL J Exp Med, 2003. 197 (5): 633-42). Briefly, 293T cells were co-transfected with a murine leukemia virus (MLV) transfection vector derived from luciferase (Op De Beeck, A., et al., J. Virol, 2004. 78 (6) 2994-3002.), a vector comprising a murine leukemia virus Gag-Pol gene construct and a vector expressing the envelope glycoprotein. Co-transfection was carried out using the Exgen® 500 transfection reagent under the conditions recommended by the supplier. The following plasmids encoding the glycoprotein of the HCV viral envelope of genotype 1b - UKN1b-5.23 (AY734976); of genotype 2b-UKN2b-1 .1 (AY734982); of genotype 3a - UKN3a-1 .28 (AY734984); of genotype 4 - UKN4-1 1 .1 (AY734986); of genotype 5- UKN5-14.4 (AY785283); of genotype 6- UKN6-5.340 (AY736194), were kindly provided by J. Bail (University of Nottingham, UK) (Lavillette, D., et al., Hepatology, 2005. 41 (2): 265-74). ). The plasmid of genotype 1a-H77 (AAB67037 with a mutation at the level of 3 amino acids: R564C, V566A, G650E) has been described in the prior art (Bartosch, B., J. Dubuisson, and FL Cosset, J. Exp. Med., 197 (5): 633-42.), And the plasmid of genotype 2a-JFH-1 (AB047639) was kindly provided by R. Bartenschlager (University of Heidelberg, Germany). The expression vector phCMV-G, encoding vesicular stomatitis virus G protein (VSV G), was used for controlled production of pseudotyped retroviral particles bearing the glycoproteins of the VSV G envelope on centers corresponding to the murine leukemia virus (VSVpp). Transfection reactions with luciferase-expressing HCVPs have been described in the literature (Op De Beeck, A., et al., J. Virol, 2004. 78 (6): 2994-3002.). Other viruses

The NADL line of the bovine viral diarrhea virus (BVDV) and the 17D line of the yellow fever virus (YFV) were used as controls. BVDVs were produced as previously described (Lecot, S., et al., J Virol, 2005. 79 (16): pp. 10826-9). The MDBK cells were seeded on the plates of 24-well plates and infected 24 hours later. The cells are infected in the presence of EGCG for 1 hour at 37 ° C with BVDV virus at a multiplicity of infection (MI) of about 1, and then they are cultured for 15 hours. The infected cells as well as the control cells are rinsed in PBS buffer and then fixed with 3% paraformaldehyde, in order to undergo immunofluorescent staining with anti-NS3 MAb (osc-23) antibodies. For YFV infections, Huh-7 cells were seeded on plates of a 24-well plate and then infected 24 hours later. The cells were infected in the presence of EGCG for 1 hour at 37 ° C with YFV virus and at an M1 of about 1, and then cultured for 23 h. The infected cells as well as the control cells are rinsed in PBS buffer, fixed with 3% paraformaldehyde. The immunofluorescence reaction is performed with an anti-E MAb 2D12 antibody. Samples of Toto 101 / Luc (Bick, MJ, et al., J. Virol, 2003. 77 (21): 11555-62.), As well as Sindbis virus (SINV) expressing luciferase (Firefly luciferase system). (kindly provided by M. MacDonald, Rockefeller University, NY, USA), were obtained by electroporation of in vitro transcribed RNA BHK-21 cells. Briefly, 1 g of RNA is mixed with 4 x 10 6 BHK-21 cells followed by an electroporation step at 25 μΡ and 140 V with a rectangular wave electroporator. The supernatant is recovered after 48 hours.

Indirect immunofluorescence microscopy.

The procedure for detecting immunofluorescent viral proteins expressed in infected cells is carried out as described in the literature (Rust, Y., et al., J. Virol, 2006. 80 (6): pp. 2832-41.). The nuclei are stained by a 5-min incubation in PBS buffer containing 1 μg / ml of 4 ', 6'-diamidino-2-phenylindole (DAPI). The slides were mounted on glass slides using the Mowiol® mounting medium (10% Mowiol, 25% glycerol, 0.1M Tris-HCl pH 8.5) and then observed using the ZEISS® AXIOPHOT fluorescence microscope equipped with a magnification of 10x and 20χ, numerical aperture objectives of 0.5. The fluorescence signal is collected with a Coolsnap ES (Photometrix) camera specifically using excitation and emission filters. fluorescence. Images are assembled and processed using Adobe Photoshop® software. Concerning the quantization step, images of areas of each strip taken at random are recorded. Cells labeled with anti-E1 MAb A4, anti-BVDV NS3 or anti-YFV E antibodies are counted as infected cells. The total number of cells was counted by nuclear tagging at DAPI. Infections are defined as the ratios of infected cells to the total number of cells.

Cell-to-cell transmission assays for HCVV viruses.

Huh-7 cells cultured in 24-well plates are infected with HCVcc for 2 hours. The inocula is removed and replaced with DMEM supplemented with GLUTAMAX®, 10% FCS and 1% low-melting agarose gel (SeaPlaque® Agarose marketed by LONZA®) containing EGCG. (50 μl) or an equivalent volume of dimethyl sulfoxide (DMSO) as a control. The cells are incubated at 37 ° C. for 3 days at the end of which the agarose is eliminated and the infectious foci are detected using indirect immunofluorescence for the HCV E1 proteins as previously described.

Link experiment.

Huh-7 cells were infected with JFH-Luc viruses for 1 h at 4 ° C (attachment / binding step) in the presence of DMSO or 50 μl of EGCG. The cells were washed with PBS and again incubated for 1 h at 4 ° C (post-attachment / receptor binding step of the host cell) in the presence of DMSO or 50 μl EGCG. The cells are then washed in order to eliminate EGCG or DMSO and then incubated for 1 hour at 37 ° C. in the presence of DMSO or 50 μl of EGCG (endocytosis / melting step). Finally, the cells are washed and then cultured with DMEM medium (Invitrogen®) supplemented with L-alanyl-L-glutamine (GLUTAMAX-I ™) and 10% fetal calf serum at 37 ° C. for 48 h. The level of infection is calculated by measuring the luciferase activity in cell lysates using the Renilla luciferase assay System kit marketed by PROMEGA®.

Quantitative "bindinq" test.

VHCcc. For quantitative binding experiments, HCVcc virus was mass produced and purified by concentration and iodixanol gradient separation. Infected cell supernatants were precipitated with 8% PEG 6000 at 4 ° C overnight and centrifuged for 25 min at room temperature. 10,000 rpm. The pellets were resuspended in 1 mL of PBS, loaded on a continuous gradient of iodixanol (10-40%), and centrifuged at 36,000 rpm for 16 h at 4 ° C. Fractions of 500 μΐ were collected and the title of each fraction was determined. The most infectious fractions were collected to carry out the experiments.

Quantitative binding test. The HCVcV virus has been in contact with the cells

Huh-7 for 1 hour at 4 ° in the presence of EGCG (50 μl), delphinidine chloride (50 μl) or porcine intestinal heparin (500 μg / ml). After 3 washes with PBS, the total (cellular and viral) RNAs were extracted using the NucleoSpin RNA II kit (Macherey-Nagel, Duren, Germany) and the quantified HCV RNA by quantitative RT-PCR (Castelain et al. ., J Clin Virol 2004). Heparin was used in parallel as a control.

Example 1

Test of the effect of different green tea catechins on HCV infection

Huh-7 cells were infected with JFH1-Rluc virus for 2 h in the presence of DMSO or 50 μl of different catechins, namely: (+) - catechin (C), (-) - epicatechin (EC), (-) - epicatechin-3-gallate (ECG), (-) - epigallocatechin (EGC) and (-) - epigallocatechin-3-gallate marketed by EXTRASYNTHESE® (EGCG EXTRASYNTHESE®) or CALBIOCHEM® (CALBIOCHEM EGCG) ®). These EGCG compositions differ in their degree of purity EXTRASYNTHESE®> 99%, CALBIOCHEM®> 95%. Since DMSO is used as a solvent for the various catechins, it serves as control tests.

(+) - catechin (C) (-) - epicatechin (EC) (-) - epigallocatechin EGC

(-) - epicatechin-3-gallate ECG (-) - epigallocatechin-3-gallate (EGCG) The cells were lysed 48 hours after infection and the expression of luciferase is quantified.

The measurement of the relative viral infection of Huh7 cells by the JFH1 -RLuc virus according to the catechin present in the medium during the infection (FIG. 1) clearly shows that neither (+) - catechin, nor (-) - epicatechin induces inhibition of viral infection by HCV. Indeed, the measurement of the relative viral infection is identical to that observed for DMSO.

On the other hand, it is noted that the EGCG that it is marketed by CALBIOCHEM® or by EXTRASYNTHESE® shows a major antiviral effect with an inhibition of viral infection greater than 95%. Concerning the ECG and EGC molecules, an antiviral effect is also observed, nevertheless, with a lower viral infection inhibition rate, of the order of about 40% and 80%, respectively.

The measurement of the relative viral infection in the presence of ECG or EGC compared with EGCG, suggests an additive effect of the 3,4,5-trihydroxy-phenyl C2 group of the chromane heterocycle and this same structure found in the C3-galloyl group of the chromane heterocycle on the antiviral role of EGCG.

The EGCG molecules, whether provided by CALBIOCHEM® or EXTRASYNTHESE®, having an identical effect on the inhibition of HCV infection, only the EGCG provided by CALBIOCHEM® will be exemplified later. Example 2

Huh-7 cells cultured in vitro were infected for 2 hours with JFH1 -RLuc virus in the presence of increasing doses of EGCG (0; 0.5; 5; 50 μΜ) or by the virus previously incubated for 45 minutes with EGCG (50 μΜ). After infection, the cells are washed with DMEM culture medium supplemented with 10% fetal calf serum and incubated in this same medium. Forty-eight hours after infection, the cells are lysed and the Renilla luciferase activity is quantified by luminometer after incubation of 20 μl of cell lysate with the substrate of luciferase.

Figure 2 shows that the inhibition of viral infection by EGCG is dose dependent.

At 50 μC, the EGCG decreases the viral infection of Huh-7 cells in culture by a factor greater than 10 (IC 50 = 5 μM). However, viral replication is not affected by EGCG (results not shown). As a result, EGCG inhibits the early stages of viral infection, namely, the steps allowing the entry of the virus into the cell.

On the other hand, no effect of EGCG is observed on the viral entry, if the uninfected cells are treated by the molecule before or after infection. Therefore, the inhibition induced by EGCG acts directly on the virus and not on the host cell. This hypothesis is supported by the observation of an increase in the inhibitory effect of EGCG when the virus is incubated with the molecule before infection (50 μΜ pretreatment).

Example 3

Proteins in the viral envelope play a major role in viral entry. In fact, in addition to allowing interaction with the host cell receptor (s), these proteins make it possible to induce fusion between the viral and cellular envelopes. In order to study the effect of EGCG on the early stages of HCV infection, a reference study model was used to express glycoproteins of the viral envelope of interest: these are the infectious viral pseudoparticles.

Different genotypes of the HCV virus are present in the world population. Thus, in order to determine the specificity of the inhibitory effect of EGCG on the viral genotype of HCV, different genotypes of envelope glycoproteins E1 and E2 of the HCV virus were studied. Infectious viral pseudoparticles (VHCpp) have been produced expressing on their surface the HCV virus E1 and E2 envelope proteins of genotypes 1a, 1b, 2a, 2b, 3, 4, 5, and 6; and, as a control, pseudoparticles of VSV virus expressing VSV envelope protein (VSVpp). The different pseudoparticles produced express luciferase to quantify the infection.

To do this, Huh-7 cells were infected for 2 hours by the VHCpp pseudoparticles of the different genotypes tested or by the VSVpp pseudoparticles in the presence of 50 μM EGCG or DMSO. Since DMSO is the solvent for EGCG, it is used as a control. At forty-eight hours post-infection, the cells are lysed and the luciferase activity is quantified by luminometer after incubation of 20 μl of cell lysate with the substrate of luciferase.

Although having no effect on VSVpp infection, EGCG (at 50 μΜ) has an inhibitory effect on HCV infection of all genotypes tested (Figure 3).

As a consequence, the inhibitory effect of EGCG directly involves the glycoproteins of the viral envelope. Thus, the inhibition of EGCG-mediated viral entry is either due to an inhibition of the attachment step ie the first interactions with the (s) cell receptor (s) host is an inhibition of the fusion step between the viral and cellular envelopes, or these two steps.

Moreover, the use of the HCVs expressing the viral glycoproteins of the different viral genotypes shows that EGCG is an effective antiviral of HCV whatever the genotype tested. Virtually no relative infection was observed in the presence of EGCG during infection with genotype 1b, 2a, 2b and 4 HCVP. Relative infections observed were very low for genotypes 1a, 3a, 5 and 6 between 5 and 13%. Thus, while a VSVpp infection induces the measurement of a relative infection of 85% in the presence of EGCG, infection with HCVpp, whatever the genotype involved, induces the measurement of a relative infection between 13 and 0%. in the presence of EGCG. These results show the high potential of EGCG as antiviral in the treatment of hepatitis C whatever the viral genotype. In addition, it is important to note that HCV genotype 1 is the most refractory to current treatments and the majority genotype in the European and US population is also inhibited by EGCG. Example 4

Example 2 demonstrates the antiviral character of EGCG against HCV regardless of its genotype. Example 2 further demonstrates that this effect is specific for HCV since EGCG does not inhibit VSV infection. While HCV is a single-stranded positive-strand RNA virus, VSV is an unsegmented negative-sense RNA virus.

Thus, in order to determine the level of specificity of EGCG within even single-stranded RNA viruses, EGCG infection experiments were performed with other viruses of the family Flaviviridae.

The yellow fever virus (YFV), the Sindbis virus (SINV) and the bovine diarrhea virus (BVDV) were tested. Infections are performed either in the presence of DMSO or EGCG at 50 μΜ. The cells infected by these different viruses were Huh-7 for YFV or SINV and MDBK cells for BVDV. The quantification of the infection was carried out by immunofluorescence after labeling the infected cells with an anti-E antibody (2D12) for the YFV virus or an anti-NS3 antibody (osc23) for the BVDV virus. A revelation step with a secondary antibody labeled with Cy3 is then performed. Regarding the SINV virus, the latter expressing luciferase, the measurement of the relative infection was carried out by the quantification of luciferase. Quantification of the presence of EGCG or DMSO in the medium during infection of the cells with YFV, BVDV and SINV viruses (Figure 4) clearly shows that EGCG does not inhibitory effect of the cell infection by any of these viruses.

As a result, EGCG is not an antiviral for other members of the family Flaviviridae. The antiviral effect of EGCG is therefore specific to HCV.

Example 5

The results described above show that EGCG inhibits the entry of the virus into cells in culture. A second mode of viral infection is the transmission of the cell-to-cell virus. To determine if EGCG also inhibits the spread of virus from cell to cell, Huh-7 cells were infected with JFH1 virus for 2 hours, then incubated in medium containing 1% agarose in the presence or absence of EGCG (at 50 μΜ). The agarose avoids the infection of the cells with the virus secreted in the medium and thus makes it possible to visualize the transmission of the cell-cell virus by contacting the cells with each other.

At seventy-two hours post-infection, the cells are fixed and the infection is detected by immunofluorescence after labeling with an anti-E1 antibody. A revelation step is then performed with a secondary antibody coupled to Cy3. The nuclei are stained with DAPI markings. The number of cells per infectious focus is quantified (Figure 5). In the presence of EGCG the infectious foci are much smaller. They contain on average 3-4 infected cells showing that the virus did not spread after infecting a cell. In contrast, control foci contain an average of 45 infected cells. In view of the above, EGCG is an inhibitor of cell-to-cell HCV virus propagation.

EGCG appears to be a good antiviral candidate for preventing re-infection of a healthy liver after transplantation in an infected patient.

Example 6

Successive infection experiments in the presence or absence of EGCG from infected cell supernatants were conducted to test the efficacy of EGCG on the virulence of an infected cell supernatant, as well as its ability to eradication of virus from infected culture supernatants. Huh-7 cells were infected with HCV virus JFH1 (PO). DMSO or 50 μM EGCG were added post-infection. The culture supernatant is collected after 48 hours and then used to infect healthy cells in the presence of DMSO or 50 μl of EGCG (P1). The supernatant of this culture (P1) is collected in turn after 48 hours and used to reinfect healthy cells (P2). This procedure is repeated twice more (until P4). The number of infected cells was quantified at each immunofluorescence passage after labeling the cells with an antibody directed against the viral envelope protein E1 (A4). The total number of cells is quantified by counting the nuclei after staining with DAPI labeling.

The study of the percentage of cells infected with each passage of a supernatant from one culture to another according to the addition of EGCG or DMSO (FIG. 6) shows that the EGCG makes it possible to eliminate the HCV from the supernatant. from the third passage and complete elimination in the fourth passage. This leads to the conclusion that EGCG is a good candidate as a healing molecule in patients infected with HCV.

Example 7

The entry of HCV into the host cell is composed of 3 steps: i) attachment of the virus or an infected host cell to the surface of the uninfected host cell, ii) interaction with the receptor (s) ( s) specific viral and iii) fusion of the viral lipid envelope and the infected host cell (plasma or endosomal membrane) allowing the introduction of the viral genome into the cytoplasm of the infected cell. In order to determine which of these steps is inhibited by EGCG, the viral entry was fractionated so as to separately study the inhibitory effect of EGCG on each of these steps (see Figure 7 A).

The step of attaching the viral particles to the cells is carried out by placing the virus in the presence of the virus followed by incubation for one hour at 4 °. The second step is by incubating the cells for one hour at 4 ° C after removal of viral inocula, allowing the attached viruses to enhance their attachment to their receptors. At 4 ° C, the process of endocytosis is blocked. Thus, the third stage of endocytosis and fusion of the viral and cellular membranes is carried out at 37 ° C. for one hour.

DMSO or 50 μΜ EGCG are added during these different steps according to the samples concerned as shown in the diagram (Figure 7A). Thus, sample 1 is the control sample that received DMSO in the first step. The other samples corresponding to the addition of 50 μΜ of EGCG during the attachment step (sample 2), interaction with the receptors of the host cell (sample 3), endocytosis and fusion of the viral lipid envelope and the infected host cell (sample 4) or during all three stages of entry (sample 5).

The cells are then incubated for 45 hours at 37 ° C. and then lysed in order to quantify the luciferase activity. Infection is expressed as a percentage of luciferase activity measured without EGCG. The experiments are performed in triplicate and the values given correspond to the average values of these three different experiments.

As shown in FIG. 7B, a sharp reduction in infection is observed when EGCG is added as early as the attachment step (samples 2 and 5). On the other hand, EGCG does not seem to have any effect on the interaction stage with the host cell receptors (sample 3) or during the endocytosis or fusion step (sample 4). All of these results demonstrate that EGCG inhibits the early steps of HCV binding to the plasma membrane of the host cell to the stage of attachment of HCV to the host cell.

Example 8

Huh-7 cells were infected with HCVcc for 2h in the presence of increasing doses of EGCG or delphinidine chloride. The infection rate was determined 34 h after inoculation by detecting the E1 envelope protein by immunofluorescence using an anti-E1 antibody (A4) and then a secondary anti-mouse IgG antibody conjugated to the fluorochrome Cy3. This experiment shows that delphinidin chloride, like EGCG, inhibits cell infection by HCVcc in a dose-dependent manner (Fig 8). The concentration inhibiting 50% of the infection (IC50) was determined in these experiments. The calculated IC50 of EGCG is about 1 1 μΜ while that of delphinidin chloride is about 3.5 μΜ.

These results show, on the one hand, that delphinidin chloride is a new inhibitor of HCV entry into cells and, on the other hand, that this molecule has superior efficacy compared to EGCG as an anti-HCV antiviral agent. .

Example 9

Example 3 demonstrates that EGCG inhibits an early step of HCV entry into cells mediated by HCV surface glycoproteins.

To determine whether the cell surface attachment step was inhibited by EGCG, quantitative binding (or binding) tests were performed. The action of Delphinidin chloride was tested in parallel. Heparin, a known inhibitor of HCV attachment at the cell surface, has been used as a positive control. The cells were incubated with purified HCVc at a multiplicity of infection for 1 hour at 4 ° C in the presence of DMSO, 50 μl of EGCG, 50 μl of delphinidine chloride or 500 μl / ml of heparin. The cells were washed 3 times with cold PBS and the total RNA extracted. The amount of fixed virus was determined by quantifying the viral genomic RNA by quantitative RT-PCR. As expected, the attachment of the virus to the cell surface in the presence of heparin is greatly reduced (FIG. 9). Similarly, in the presence of EGCG or delphinidine chloride, a sharp decrease in virus attachment to the cell surface is also observed. All of these results show that both EGCG and delphinidine chloride, probably by acting directly on the viral particle, inhibit viral entry by preventing the attachment of HCVcc to the cell surface.

Claims

1 .- Compound of formula (I)

in which :

• X is O when a is a single bond or 0 ⁺ when a is a double bond,

R3, R5 and R7 are independently of each other, a hydrogen atom, an OH group, an O-glycosyl group, a (C1 -C18) alkoxyl or a group of formula (II)

R4 and R6 are independently of each other, a hydrogen atom or an OH group,

A and b identical or different being either a single bond or a double bond,

or a pharmaceutically acceptable salt or ester thereof, said compound of formula (I) being in the form of a pure stereoisomer or a mixture of enantiomers and / or diastereoisomers, including racemic mixtures,

for use as an antiviral agent in the treatment and / or prevention of infection with hepatitis C virus (HCV).

2. - Compound for use according to claim 1, characterized in that said compound is an antiviral agent by inhibiting infection of a host cell with HCV and / or HCV transmission of an infected host cell to another host cell.

3. - Compound for use according to claim 2, characterized in that said compound is an antiviral agent by inhibiting the entry of HCV into a host cell.

4. Compound for its use according to any one of claims 1 to 3, characterized in that said compound is an antiviral agent by inhibiting the adhesion of the hepatitis C virus, or a host cell infected by hepatitis C virus, at the membrane of a non-infected host cell.

5. Compound for its use according to any one of claims 2 to 4, characterized in that said host cell is a hepatocyte cell.

6. - Compound for use according to any one of claims 1 to 5, characterized in that said compound is an antiviral agent by inhibiting the interaction of HCV surface glycoproteins with at least one target protein of a cell host.

7. - Compound for its use according to claim 6, characterized in that said compound is an antiviral agent by inhibiting the interaction of glycoproteins E1 and / or E2 HCV with at least one target protein of a host cell.

8. - Compound for use according to any one of claims 1 to 7 characterized in that the treatment and / or prevention of HCV infection is for a patient resistant or intolerant to the treatment of an infection by HCV by an immunomodulating agent and / or an inhibitor of viral metabolism.

9. - Compound for its use according to any one of claims 1 to 8, characterized in that the compound according to the invention is a compound of formula (III):

in which :

R 6 is a hydrogen atom or an OH group, and

or a pharmaceutically acceptable salt or ester thereof.

10. Compound for its use according to any one of claims 1 to 8, characterized in that the compound according to the invention is a compound of formula (IV)

in which :

R 6 is a hydrogen atom or an OH group, and

or a pharmaceutically acceptable salt or ester thereof.

1 1 .- Compound for its use according to any one of claims 1 to 8, characterized in that the compound according to the invention is a compound of formula (V)

in which :

or a pharmaceutically acceptable salt or ester thereof.

12. Compound for its use according to any one of claims 1 to 8, characterized in that the compound according to the invention is a compound of formula (I)

in which,

The groups R1, R5 and R7 are hydroxyl groups,

R2 is a hydroxyl group or a hydrogen atom,

R 3 is a hydroxyl group, a hydrogen atom or a galloyl group of formula (II)

• R6 is a hydrogen atom,

or a pharmaceutically acceptable salt or ester thereof.

13. A compound for its use according to any one of claims 1 to 12, characterized in that said compound is selected from the group consisting of anthocyanidins, anthocyanins, flavonols and flavan-3-ols.

14. A compound for its use according to any one of claims 1 to 9, 1 1 to 13 characterized in that said compound is an anthocyanidin selected from the group consisting of delphinidin, Pulchelidine or tricetinidine or a flavan-3 -ol selected from the group consisting of epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin (GC), catechin gallate (CG), gallocatechin gallate (GCG), epicatechin (EC), epicatechin gallate (ECG), their pharmaceutically acceptable salts and esters, and mixtures thereof.

15. A compound for its use according to any one of claims 1 to 9 and 1 1 to 14, characterized in that said compound is epigallocatechin (EGC), epicatechin gallate (ECG), epigallocatechin gallate ( EGCG), delphinidine or a pharmaceutically acceptable salt or ester thereof.

16. Compound for use according to any one of claims 1 to

15, characterized in that said compound is co-administered with an additional agent for the treatment and / or prevention of HCV infection.

17. - Compound for use according to any one of claims 1 to 16, characterized in that said compound is the only antiviral agent administered for the treatment and / or prevention of infection with HCV.

18. - Ex vivo method for reducing the infectivity or inactivation of a hepatitis C virus (HCV), said method comprising a step of bringing said HCV into contact with a compound of formula (I)

in which :

• X is O when a is a single bond or 0 ⁺ when a is a double bond,

R4 and R6 are independently of each other, a hydrogen atom or an OH group,

A and b identical or different being either a single bond or a double bond,

The ex vivo inactivation method of claim 18, wherein said HCV is present in a biological sample.