AU2011266864C1

AU2011266864C1 - Compositions containing flavones and anthelmintics

Info

Publication number: AU2011266864C1
Application number: AU2011266864A
Authority: AU
Inventors: Fabrice Guegnard; Dominique Kerboeuf
Original assignee: Institut National de la Recherche Agronomique INRA
Current assignee: Institut National de la Recherche Agronomique INRA
Priority date: 2010-06-18
Filing date: 2011-06-10
Publication date: 2016-06-02
Anticipated expiration: 2031-06-10
Also published as: EP2582370A1; FR2961399A1; WO2011157936A1; NZ605982A; ZA201209745B; AU2011266864B2; AU2011266864A1

Abstract

The invention relates to compositions containing flavones and anthelmintics and to the uses thereof for treating nematode-induced parasitoses.

Description

COMPOSITIONS BASED ON FLAVONES AND ANTHELMINTICS

[0001] The present invention relates to compositions based on flavones and anthelmintics and uses thereof for treating parasitoses.

[0002] Polyparasitism is common in the majority of higher eukaryotic organisms, without it always being possible to combat the parasites responsible effectively. Although therapeutic agents belonging to various chemical classes exist, it is still very difficult to detect and eradicate a parasite in a higher organism. In fact, on the one hand, the resultant disorders (vitamin and mineral deficiencies, anaemia, abnormal haematopoiesis, immune system deficiency, etc.) are not always specific to one parasitosis or to one type of parasite, and on the other hand, the intensity of the disorders observed in the host depends on many factors, such as its resistance to parasites (itself depending on its age, sex, general condition, environment and lifestyle), but also on the number and different types of parasites that it is feeding unknowingly.

[0003] Parasitoses can be prevented by modifying the ecosystem (for example by destroying the mosses on pastureland which constitute a shelter for the free stages of parasites), and especially by chemical treatment. The latter method of prophylaxis is restricting and sometimes toxic for the host to be treated and for the environment in which residues are released. Moreover, resistant parasites are gradually selected from the parasite population.

[0004] The appearance of parasites that are resistant to a class of antiparasitics is particularly detrimental on farms where farmers then administer antiparasitics to their animals at doses often much higher than those recommended, thinking that this will increase their efficacy. The toxicity of the treatments therefore becomes significant for the animals treated, and generally does not allow the elimination of the most resistant parasites, which are moreover favoured by the disappearance of the so-called sensitive parasites. Therefore none of these solutions is without consequence for the infested host or for the environment.

[0005] Parasites are also capable of becoming resistant to several chemical classes of antiparasitics by the mechanism of multidrug resistance (MDR), which is known for other classes of therapeutic agents and which also relates to antiparasitics. In this case, resistance to chemicals mainly involves the presence of efflux membrane pumps, which enable the parasites to prevent the penetration of toxic compounds into their cytoplasm and return them to the extracellular fluid. The best-known efflux pump is glycoprotein P (P-gp or Pgp), which belongs to the family of ABC transporters (ATP Binding Cassette) (Xu, M., Molento, M., Blackhall, W., Ribeiro, P., Beech, R., Prichard, R. Ivermectin resistance in nematodes may be caused by alteration of P-glycoprotein homolog. Mo/. Biochem. Parasitoi. (1998), 91(2): 327-35); Kerboeuf, D., Blackhall, W., Kaminsky, R., von Samson-Himmelstjerna, G. P-glycoprotein in helminths: function and perspectives for anthelmintic treatment and reversal of resistance. Int. J. Antimicrob. Agents. (2003), 22(3): 332-46). The two publications mention the use of inhibitors of this protein pump for reinforcing the action of two antiparasitics: moxidectin (MOX) and ivermectin (IVM). The first publication by Dupuy eta/. describes the subcutaneous co-administration of quercetin (a natural compound of the flavonoid family) and moxidectin, with quercetin making it possible to increase the bioavailability of moxidectin in vivo in the lamb; in this article, the authors show that there is blocking of the host's glycoprotein P, but mention no effect in the parasite or on resistant nematodes. The increase of moxidectin in the host's tissues certainly leads to an increase in the concentration of anthelmintic at the site of implantation of the parasite but at the same time, the residues are doubled in the vertebrate's body and in the products that it excretes (bile and intestinal secretions) thus leading to an undesirable doubling of contamination of the environment. (Dupuy, J., Larrieu, G., Sutra, J. F., Lespine, A. and Alvinerie, M. Enhancement of moxidectin bioavailability in lamb by a natural flavonoid: quercetin. Veterinary Parasitology (2003), 112(4): 337-347). The second publication by Bartley etai. for its part describes the potentiating effect in vitro of quercetin on the action of ivermectin against the nematode Teladorsagia circumcincta. Nevertheless, in order to obtain an effect identical to that observed for the reference inhibitor valspodar, the dose of quercetin must be 12 times higher in sensitive nematodes and 27 times higher in resistant nematodes (Bartley, D. J., McAllister, H., Bartley, Y., Dupuy, J. Menez, C., Alvinerie, M., Jackson, F., Lespine, A. P-glycoprotein interfering agents potentiate ivermectin susceptibility in ivermectin sensitive and resistant isolates of Teladorsagia circumcincta and Haemonchus contortus. Parasitology (2009), 136: 1081-1088, Cambridge University Press).

[0006] However, although quercetin seems in these two cases to reinforce the action of the antiparasitics (MOX and IVM), the latter also inevitably inhibits the P-gp pumps of vertebrates (see Dupuy eta/., cited above), thus depriving them of a vital detoxification system.

[0007] Consequently there is a great need for new antiparasitic treatments, which are effective both against sensitive and against resistant parasites, and which moreover preserve the health of the infested host as well as its environment.

[0008] The inhibitors of P-gp pumps include natural compounds belonging to the flavonoid family. W02009/018326 describes conditions for formulating various flavonoids for various therapeutic applications and, among other things, an increased effect with respect to human P-gp resulting from improved dissolution of fisetin. Kitagawa etai for their part describe the inhibitory action of flavonoids such as kaempferol, baicalein, myricetin, fisetin, and morin on the P-gp pumps of human KB-C2 cells, namely by controlling the accumulation of an antineoplastic agent within the latter (Kitagawa, S., Nabekura, T., Takahashi, T., Nakamura, Y., Sakamoto, H., Tano, H., Hirai, M., Tsukahara, G. Structure-activity relationships of the inhibitory effects of flavonoids on P-glycoprotein-mediated transport in KB-C2 cells. Biol. Pharm. Bull. (2005), 28(12): 2274-8). However, although fisetin is mentioned in both these publications, Kitagawa etai demonstrate that it has little inhibitory effect on human P-gp, in contrast to quercetin.

The inhibitory action of quercetin on the P-gp of nematodes proved to be comparable to that found by Kitagawa etal. with respect to human P-gp. Therefore there was no reason to think that the inhibitory action of other flavonoids of the same chemical family would be greater on the P-gp of nematodes relative to the P-gp of vertebrates.

[0009] Wong etal. (Journal of Antimicrobial Chemotherapy, 2009, 63, 1179-1190) describe a synergistic effect between quinacrine, an antimalarial derived from quinine and a dimer of apigenin the structure of which is different from the compounds used in the present invention on a pentamidine-resistant Leishmania protozoon. This synergistic action is connected with the respective effects of each compound and not with a modification of the bioavailability of one by the other.

[0010] WO 02/069949 describes compositions comprising circilliol or trimethoxyflavones combined with antiparasitic compounds and suitable for treating parasitic diseases in humans; none of the parasites mentioned is a nematode. Moreover, the only examples relate to antitumour activity.

[0011] WO 2008/0859925 describes the activity of novel flavones originating from Struthio/a argenta on the nematode H. contortus. The majority of these flavones are inactive in vitro and in vivo.

[0012] WO 01/03681 describes the use of derivatives of flavones, optionally combined with other anti-infective agents in the treatment of parasites which are not nematodes. There is not a single mention of any synergy between the flavones and the compounds with which they might be combined.

[0013] WO 2007/135592 describes dimers of flavones and their capacity for reducing the drug resistance of certain parasites. The parasites specifically described are those of the genus Leishmania and the drugs are stibogluconate and pentamidine. The dimers of apigenin inhibit and reverse pentamidine resistance in the genus Leishmania whereas the monomers are not active.

[0014] Young-Ah Yoon etal. report the results of a structure-activity study on 13 flavones tested on C. e/egans, a free-living nematode used as a model for studying anthelmintic activity. These flavones are never combined with other antiparasitics and the problems of drug resistance are not discussed.

[0015] The present invention therefore flows from the surprising discovery made by the inventors that certain flavonoids that are inhibitors of P-gp of vertebrates do not possess the same inhibitory efficacy with respect to P-gp of parasites on which they proved much more active. The present invention accordingly offers new antiparasitic treatments based on flavones, more specifically targeting the P-gp of parasites, in contrast to those based on quercetin described by Dupuy et al., and by Bartley et al. cited above which act both on the P-gp of the host and on that of the parasite.

[0015a] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

[0016] One aim of the present invention is therefore to provide new preventive and therapeutic antiparasitic treatments, said treatments being very safe for the host to be treated and for its environment, and moreover displaying considerable efficacy against sensitive nematodes and/or resistant nematodes, even with a dose of antiparasitic agent less than normal. This invention consequently offers three major advantages. Firstly, it makes it possible to increase the bioavailability of the antiparasitics in the parasites, and thus reduce the amount to be used and to be administered to the host because of increased efficacy against the parasites. It then relates to inhibitors that are more specific to the P-gp of parasites, having for some an efficacy at least as great as quercetin, and without the drawbacks of this molecule for the vertebrate treated (the drawback being inhibition of its own detoxification system by P-gp). Finally, it offers new antiparasitic compositions that are effective against susceptible and/or resistant parasites, by lowering the level of resistance of the latter.

[016aa] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0016a] According to a first aspect the invention provides use of a composition comprising at least one anthelmintic compound and at least one flavone compound, the said flavone compound being chosen among: - a compound of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, and - a morin, provided that the flavone of formula (I) is not quercetin, for preparing a medicinal product that is able to increase the bioavailability of anthelmintics in nematodes; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.

[0016b] Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

[0016c] According to a second aspect the invention provides a composition for pharmaceutical or veterinary use comprising at least one anthelmintic compound and at least one flavone, the said flavone being chosen among: - a flavonol corresponding to the following formula (III):

in which R1, R2, R3, R5 and R7 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (III) by its anomeric carbon via a glycosidic bond, and - a morin; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.

[0016d] According to a third aspect the invention provides a method of prophylaxis or treatment of parasite infection comprising administering to a subject in need thereof a composition comprising at least one anthelmintic compound and at least one flavone compound, the said flavone compound being chosen among: - a compound of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, and - a morin, provided that the flavone of formula (I) is not quercetin; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.

[0017] The present invention relates firstly to a composition for pharmaceutical or veterinary use comprising at least one anthelmintic compound and at least one compound of one of the flavonoid families, the flavones of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of a pharmaceutically acceptable salt, and is present in a quantity making it possible to increase the bioavailability of the at least one anthelmintic compound by inhibition of the glycoprotein P in nematodes, provided that the flavone of formula (I) is not quercetin.

[0018] By "anthelmintic compound" (or antihelminthic compound) is meant an antiparasitic compound making it possible to kill (vermicidal action) at least one type of worm belonging to the Helminths phylum of the Metazoa or to cause it to be expelled (vermifugal action) from the host. The anthelmintic activity of a compound can for example be measured by an Egg Hatch Test (EHT)of the parasites for the compounds belonging to the benzimidazole family, or by a larval development test (LDT) for the macrocyclic lactones, and by any other equivalent type of test.

[0019] By "sugar" is meant equally holosides, and diholosides and triholosides; there may be mentioned, as non-limiting examples: apioglucose, galactose, glucose, glucopyranose, glucuronic acid, laminaribiose, neohesperidose, primeverose, rhamnose, robinose, rutinose and sambubiose.

[0020] By "glycosidic bond" is meant an O-glycosidic or C-glycosidic bond, preferably O-glycosidic.

[0021] By "glycoprotein P" (P-gp) is meant the glycoprotein known to a person skilled in the art for its involvement in multidrug resistance. It is a transmembrane receptor of the plasma membrane, occurring in various forms in numerous eukaryotes, and capable of expelling certain xenobiotics present in the cytoplasm to the extracellular fluid using the energy supplied by consumption of ATP.

[0022] By "inhibition of glycoprotein P" is meant a lowering of the antixenobiotic activity of P-gp. This lowering is reflected in a decrease of LD50 (lethal dose killing 50% of the population) for a xenobiotic (in particular an anthelmintic) and an organism under consideration. This lowering of LD50 can be detected by a larval development test (LDT), regardless of which compound is used. The inhibition can also be demonstrated by in vitro measurement of the efflux activity of the pump ("rhodamine 123 assay").

[0023] By "nematode" is meant any type of roundworm belonging to the Helminths phylum of the Metazoa. Examples of major genera of nematodes in parasite biology and pathology are given below.

[0024] In the Secernentasida class:

Order Rhabditorida - Family Rhabditidae, the free-living nematode and biological model Caenorhabditis;

Order Strongylorida, Family Strongyloididae: Strongyioides; - Family Ancylostomatidae: Ancylostoma, Bunostomum, Necator, Uncinaria; - Family Strongylidae: Strongylus, Chabertia, Oesophagostomum; - Family Syngamidae: Syngamus; - Family Tricostrongylidae: Cooperia, Haemonchus, Hyostrongylus, Ostertagia, Teladorsagia, Trichostrongylus, Graphidium, Nematodirus, Heligmosomoides, Nippostrongylus, Ornithostrongylus, Amidostomum; - Family Metastrongylidae: Dictyocaulus, Metastrongylus, Angiostrongylus, Cystocaulus, Muellerius, Protostrongylus;

Order Ascaridorida: - Family Heterakidae: Heterakis, - Family Ascarididae: Ascaris, Parascaris, Toxocara; - Family Oxyuridae: Aspiculuris, Enterobius, Oxyuris, Syphacia;

Order Spirurorida: - Family Filariidae: Fiiaria\ - Family Onchocercidae: Brugia, Litomosoides, Wuchereria, Dirofilaria, Loa, Onchocerca; - Family Stephanofilaridae: Setaria; [0025] In the class Adenophorasida:

Order Dorilaimorida: - Family Trichuridae Trichuris, Capillaria; - Family Trichinellidae Trichinella; [0026] Examples of flavones represented by general formula (I) are: acacetin, apigenin, chrysin, chrysoeriol, diosmetin, eupatilin, galangin, luteolin, oroxylin A, robinetin, scutellarein, tricine, wogonin, and in particular baicalein, fisetin, kaempferol, myricetin, geraldol, as well as silybin.

[0027] By "hydroxyl precursor group" is meant any group that can be metabolized in vivo to give an OFI group, for example an ester group, an ether group, an alkoxy group, in particular methoxy (as in the formula of geraldol), a sulphonate group, a ketone or an aldehyde. As examples of an ester group, there may be mentioned the -(CO)-R groups where R represents a hydrogen atom or a linear or branched (C1-C5) alkyl group selected from the group comprising methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, and 2-methylbutyl. These alkyl groups can be partially or totally halogenated, i.e. the hydrogen atoms can be partially or totally replaced with identical or different halogen atoms. There may be mentioned as examples the chloromethyl, dichloromethyl, trichloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, chlorofluoromethyl, dichlorofluoromethyl, chlorodifluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 2-chloro-2-fluoroethyl, 2-chloro-2,2-difluoroethyl, 2,2-dichloro-2-fluoroethyl, 2,2,2-trichloroethyl and pentafluoroethyl groups.

[0028] In an advantageous embodiment, only the R7 group of general formula (I) is a sugar as defined above.

[0029] In an advantageous embodiment, said composition for pharmaceutical or veterinary use is a composition in which at least one flavone of formula (I) corresponds to the following formula (II):

in which R1, R2, R3, R4, R5, R6 and R7 are as defined above.

[0030] In another advantageous embodiment of the invention, said composition for pharmaceutical or veterinary use is a composition in which at least one flavone of formula (I) is a flavonol corresponding to the following formula (III):

in which R1, R2, R3, R5 and R7 are as defined previously, said flavonol of formula (III) in particular being selected from the group comprising fisetin and myricetin.

[0031] By "fisetin" is meant the flavone of formula (III) in which R1, R2 and R7 represent an OH group and R3 and R5 represent a hydrogen atom.

[0032] By "myricetin" is meant the flavone of formula (III) in which R1, R2, R3, R5 and R7 represent an OH group.

[0033] In another even more advantageous embodiment, the present invention relates to a composition for pharmaceutical or veterinary use, in which at least one anthelmintic present in a composition for pharmaceutical or veterinary use is selected from the group comprising: - levamisole; - macrocyclic lactones selected from the group comprising avermectins such as ivermectin (IVM), eprinomectin (EPR), abamectin (ABA), doramectin (DOR), or from the group comprising milbemycins such as moxidectin (MOX); - derivatives of benzimidazole selected from albendazole (ABZ), thiabenzole (TBZ), mebendazole, fenbendazole, oxfendazole, febantel, and oxibendazole.

[0034] Another subject of the present invention is a composition for pharmaceutical or veterinary use according to any one of the preceding definitions, for use in the treatment or prevention of a parasitosis in a vertebrate.

[0035] By "parasitosis" in particular is meant a helminthiasis.

[0036] In an advantageous embodiment of the invention, the parasitosis is a nematodiasis.

[0037] By "nematodiasis" is meant a parasitosis due to a nematode, in particular a trichostrongylosis, for example a haemonchosis.

[0038] By "haemonchosis" is meant a parasitosis by the nematode Haemonchus contortus, the study model for trichostrongyloses.

[0039] In a particularly advantageous embodiment of the invention, the parasitosis involves at least one so-called resistant parasite.

[0040] By "parasite" is meant an animal or a eukaryotic plant which lives for at least a part of its existence at the expense of another organism.

[0041] By "resistant" is meant a chemoresistant parasite. This chemoresistance is present when the frequency of parasites capable of tolerating the usual doses of antiparasitic compounds is greater within a population than in a normal population of parasites of the same species. It is, moreover, transmissible to the progeny. (PRICHARD R.K. eta/. The problem of anthelmintic resistance in nematodes. Australian Veterinary Journal. (1980), 56: 239-51). The different types of resistance are: simple resistance (resistance to a single molecule), family resistance (resistance to at least two compounds of one and the same family of antiparasitics), multiple resistance (resistance to at least two compounds belonging to different families of antiparasitics) and crossed resistance (resistance to several antiparasitics conferred by one or more mutations to a gene). Each resistance can moreover be primary (having appeared before the start of the antiparasitic treatment) or secondary (which appeared during said treatment). The term "resistant" used in the context of the present invention refers to simple resistance at least, but the invention applies to cases of crossed, family or multiple resistance, whether of the primary or secondary type. Moreover, this resistance can be induced by a great many factors. For example, it has been shown that resistant strains of H. contortus possess a number of P-gp efflux pumps greater than normal, and consequently eliminate doses of antiparasitics more easily (KERBOEUF, D. P-glycoprotein in helminths: function and perspectives for anthelmintic treatment and reversal of resistance. Int JAntimicrob Agents. (2003), 22(3): 332-46).

[0042] In an advantageous embodiment of the invention, the parasite is a resistant nematode.

[0043] In another advantageous embodiment of the invention, the vertebrate is selected from the group comprising bovines, caprines (sheep and goats), Equidae, birds and humans.

[0044] The dosage of the anthelmintic and of the flavones of formula (I) depends in particular on the method of administration, and is easily determined by a person skilled in the art. Likewise, the choice of an acceptable pharmaceutical or veterinary vehicle is determined by a person skilled in the art. The compounds of formula (I) can moreover be administered in an encapsulated form, in particular nanoencapsulated, in pegylated liposomes, or in forms with sustained release or sequential release or in forms including solubilizers (for example cyclodextrins as described in W02009/018326) so as to increase their bioavailability.

[0045] The treatment can be continuous or sequential, delivering said compounds, pharmaceutical or veterinary compositions continuously and optionally constantly, or discontinuously, in one or more daily administrations, optionally repeated for several days, either consecutive, or with a latency without treatment between the administrations.

[0046] The compounds, as well as the pharmaceutical or veterinary compositions of the invention can in particular be administered by the enteral or parenteral systemic (general) route, and by the topical route.

[0047] By "enteral route" in particular is meant the oral route or per os, the perlingual route as well as the rectal route.

[0048] By "parenteral route" in particular is meant the subcutaneous route, the intramuscular route and the intravenous route.

[0049] By "topical route" in particular is meant the nasal route, the pulmonary route, the cutaneous or percutaneous or transdermal route.

[0050] As an example, there may be mentioned a composition in which the at least one anthelmintic is present in a unit quantity: - from 5 to 10 mg/kg of live weight of the vertebrate to be treated for levamisole, or - from 5 to 600 pg/kg of live weight of the vertebrate to be treated for macrocyclic lactones, or - from 5 to 300 mg/kg of live weight of the vertebrate to be treated for benzimidazole derivatives, and the at least one flavone in the formula is present in a unit quantity from 2.5 to 50 mg/kg of live weight of the vertebrate to be treated, preferably from 2.5 to 40 mg/kg of live weight of the vertebrate to be treated and even more preferably from 2.5 to 30 mg/kg of live weight of the vertebrate to be treated.

[0051] Another subject of the present invention is a composition for pharmaceutical or veterinary use comprising at least one anthelmintic compound and at least one flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group, and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of a pharmaceutically acceptable salt, and making it possible to increase the bioavailability of the anthelmintic compound by the inhibition of glycoprotein P in nematodes, provided that the flavone of formula (I) is not quercetin, for administration that is simultaneous, sequential or spread overtime.

[0052] Yet another subject of the present invention is a composition comprising at least one anthelmintic agent and at least one flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, provided that the flavone of formula (I) is not quercetin, for lowering the resistance of nematodes to the at least one said anthelmintic agent.

[0053] Another subject of the invention is therefore a method for lowering the resistance of nematodes to at least one anthelmintic agent, said method comprising administration, to a subject needing it, of a compound of formula (I) in free form or in the form of a pharmaceutically acceptable salt, provided that the flavone of formula (I) is not quercetin.

[0054] In a particular embodiment of the invention, the composition for pharmaceutical or veterinary use according to any one of the preceding definitions is formulated for oral, parenteral or topical administration.

[0055] Yet another subject of the present invention is a combination for increasing the bioavailability of at least one anthelmintic compound that comprises the at least one said anthelmintic compound and a sufficient quantity of at least one flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, provided that the flavone of formula (I) is not quercetin, in a form usable for co-administration.

[0056] Yet another subject of the present invention is the use of at least one flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, provided that the flavone of formula (I) is not quercetin, for preparing a medicinal product that is able to inhibit glycoprotein P in nematodes and for treating parasitoses, in particular nematodiases.

[0057] Finally, another subject of the present invention is the use of at least one flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, provided that the flavone of formula (I) is not quercetin, for preparing a medicinal product that is able to increase the bioavailability of anthelmintics in nematodes.

[0058] In an advantageous embodiment of the use according to the invention, at least one flavone of formula (I) corresponds to the following formula (II):

in which R1, R2, R3, R4, R5, R6 and R7 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (II) by its anomeric carbon via a glycosidic bond.

[0059] In another advantageous embodiment of the use according to the invention, at least one flavone of formula (I) is a flavonol corresponding to the following formula (III):

in which R1, R2, R3, R5 and R7 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (III) by its anomeric carbon via a glycosidic bond, said flavonol of formula (III) in particular being selected from the group comprising fisetin and myricetin.

[0060] In another advantageous embodiment of the use according to the invention, at least one anthelmintic is selected from the group comprising: - levamisole; - macrocyclic lactones selected from the group comprising avermectins such as ivermectin, eprinomectin, abamectin, doramectin, or from the group comprising milbemycins such as moxidectin; - the derivatives of benzimidazole selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel, and oxibendazole.

[0061] According to the invention, the compounds are used in the treatment or prevention of a parasitosis in a vertebrate, in particular a nematodiasis, in particular a haemonchosis.

[0062] In a particularly advantageous embodiment of the invention, the parasitosis involves at least one so-called resistant parasite, in particular a resistant nematode.

[0063] In an advantageous embodiment of the invention at least one anthelmintic compound and at least one flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of a pharmaceutically acceptable salt, and making it possible to increase the bioavailability of the anthelmintic compound by inhibition of glycoprotein P in nematodes, provided that the flavone of formula (I) is not quercetin, are used for administration that is simultaneous, sequential or spread overtime.

[0064] Finally the present invention relates to a method for increasing the bioavailability of an anthelmintic in nematodes comprising the administration, to a subject needing it, of a compound of formula (I) in free form or in the form of a pharmaceutically acceptable salt, provided that the flavone of formula (I) is not quercetin.

[0065] The invention is illustrated by Examples 1 to 3 and Figures 1 to 7 given below.

[0066] Figures 1a and 1b are histograms representing the results obtained for tests of accumulation of rhodamine 123 according to the protocol given in Example 1. They relate to 14 flavonoids and 3 other assimilated compounds (naphthoflavone, silybin and xanthone) tested at different concentrations (20, 50, 100, and 200 μΜ). In these figures, the ordinate shows the percentage accumulation of rhodamine 123 relative to the control without modulator in the eggs of the model nematode Haemonchus contortus, sensitive (FlcS-Weyb - filled rectangles) or resistant (FIcR-Guad - hatched rectangles). The abscissa gives the name and concentration of the compounds tested, which were added individually to the media containing said eggs: [0067] 1: Control; 2: Vanadate 500 pM; 3: Kaempferol 20 pM; 4: Kaempferol 50 pM; 5: Kaempferol 100 pM; 6: Kaempferol 200 pM; 7: Fisetin 20 pM; 8: Fisetin 50 pM; 9: Fisetin 100 pM; 10: Fisetin 200 pM; 11: Apigenin 20 pM; 12: Apigenin 50 pM; 13: Apigenin 100 pM; 14: Apigenin 200 pM; 15: Genistein 20 pM; 16: Genistein 50 pM; 17: Genistein 100 pM; 18:

Genistein 200 pM; 19: Baicalein 20 pM; 20: Baicalein 50 pM; 21: Baicalein 100 pM; 22: Baicalein 200 pM; 23: Biochanin A 20 pM; 24: Biochanin A 50 pM; 25: Biochanin A 100 pM; 26: Biochanin A 200 pM; 27: Chrysin 20 pM; 28: Chrysin 50 pM; 29: Chrysin 100 pM; 30: Chrysin 200 pM; 31:

Flavanone 20 pM; 32: Flavanone 50 pM; 33: Flavanone 100 pM; 34: Flavanone 200 pM; 35: Flavone 20 pM; 36: Flavone 50 pM; 37: Flavone 100 pM; 38: Flavone 200 pM; 39: Formononetin 20 pM; 40: Formononetin 50 μΜ; 41: Formononetin 100 μΜ; 42: Formononetin 200 μΜ; 43: Galangin 20 μΜ; 44: Galangin 50 μΜ; 45: Galangin 100 μΜ; 46: Galangin 200 μΜ; 47: Myricetin 20 μΜ; 48: Myricetin 50 μΜ; 49: Myricetin 100 μΜ; 50: Myricetin 200 μΜ; 51: Naphthoflavone 20 μΜ; 52: Naphthoflavone 50 μΜ; 53: Naphthoflavone 100 μΜ; 54: Naphthoflavone 200 μΜ; 55: Naringenin 20 μΜ; 56: Naringenin 50 μΜ; 57: Naringenin 100 μΜ; 58: Naringenin 200 μΜ; 59: Quercetin 20 μΜ; 60: Quercetin 50 μΜ; 61: Quercetin 100 μΜ; 62: Quercetin 200 μΜ; 63: Silybin 20 μΜ; 64: Silybin 50 μΜ; 65: Silybin 100 μΜ; 66: Silybin 200 μΜ; 67: Xanthone 20 μΜ; 68: Xanthone 50 μΜ; 69: Xanthone 100 μΜ; 70: Xanthone 200 μΜ.

[0068] The quantity of R123 accumulating in the eggs in the presence of a powerful inhibitor of ATPase, sodium orthovanadate, corresponds approximately to a value of 500%. Absence of results corresponds to concentrations of products presenting solubility problems.

[0069] Figures 2a and 2b present the results given in Figure 1 in the form of curves. The abscissa in Figures 2a and 2b shows the concentration (in μΜ) of each potential inhibitor. The ordinate is identical to Figures 1a and 1b. Figure 1a: sensitive H. contortus, Figure 1b: resistant H. contortus.

[0070] Figures 3a, 3b and 3c represent the best three results obtained for the larval development tests (LDT). Each figure has, for the ordinate, the percentage of larvae that develop as a function of the amount of anthelmintic used, shown on the abscissa. The anthelmintics used are eprinomectin for Figures 3a and 3b and doramectin for Figure 3c. Each curve represents a different combination of an anthelmintic and an inhibitor. The combination anthelmintic and its solvent DMSO 1% is used as negative control (absence of P-gp inhibitor).

[0071] Figure 4 represents other results obtained for the larval development tests (LDT). The two histograms (that on the left for the sensitive nematodes and that on the right for the resistant nematodes) show, on the ordinate, the percentage additional reduction of parasites relative to the anthelmintic alone for different combinations of anthelmintic (doramectin or eprinomectin) and inhibitor (fisetin or myricetin). The abscissa of the histograms gives the type of anthelmintic used.

[0072] Figure 5 presents the results for the additional reduction (%) connected with addition of P-gp inhibitor to the anthelmintic for the worm count and the egg count (EPG, eggs per gram of faeces) of the resistant nematode H. contortus obtained for an in vivo test in the lamb. The anthelmintic and the inhibitor used for this test are among those that gave the best results in in vitro tests, i.e. doramectin and fisetin (respectively). As eprinomectin does not currently have MA for sheep in France, it was not used for this test. Ordinate: percentage additional reduction in parasite burden and in egg count; abscissa: results for EPG (left), and results for parasite burden (right).

[0073] Figures 6a, 6b, 6c give the results obtained for a new in vivo test in the lamb for the reduction in parasite burden and in the faecal egg count of resistant H. contortus. Figure 6a shows the results obtained for the EPG test. The percentage reduction in faecal egg count is shown on the ordinate. In Figure 6b, the ordinate shows the parasite burden expressed in worm count 14 days after treatment, and in Figure 6c the percentage reduction in parasite burden (based on the data in Figure 6b). The abscissa in these three figures shows the amount of anthelmintic administered (expressed in pg/kg of live weight of the vertebrate treated).

[0074] Example 1: results obtained for rhodamine 123 accumulation assays ("R123 assay") with spectrofluorometer quantification [0075] Materials [0076] Animal infested with "Guadeloupe" resistant strain of Haemonchus contortus (FIcR-Guad); [0077] Preparation of the solutions: - solution of rhodamine 123 (Sigma-Aldrich® - R8004 - stored since dissolution, 19/10/06, in liquid nitrogen - [R123] = 1000 pg/ml - MW = 380.8 g/mol): daughter solution at 1.5 μΜ (0.57 pg/mL): 114 pi of R123 at 1000 pg/mL q.s.f. 200 ml_ of D.W. (distilled water); - solution of sodium orthovanadate (vanadate): vanadate: Sigma-Aldrich® - S6508 - MW = 183.91 g/mol; solution of vanadate at 50 mM: 18.4 mg of vanadate in powder form q.s.f. 2 ml_ of D.W.; - solutions of fisetin: fisetin: Sigma-Aldrich® - F4043 - MW = 286.24 g/mol; solution of fisetin - 20 mM: 1.43 mg of fisetin in powder form q.s.f. 250 pi of DMSO; solution of fisetin - 5 mM: 50 μΙ of fisetin at 20 mM q.s.f. 200 μΙ of DMSO; - solutions of quercetin: quercetin: Sigma-Aldrich® - Q0125 - MW = 338.26 g/mol; solution of quercetin - 20 mM: 1.69 mg of quercetin in powder form q.s.f. 250 μΙ of DMSO; solution of quercetin - 5 mM: 50 μΙ of quercetin at 20 mM q.s.f. 200 μΙ of DMSO.

[0078] Protocol: Accumulation of rhodamine 123 in the presence or absence of modulators - Accumulation of R123: introduce 15 000 eggs of HcR-Guad into a 5mL glass tube. After centrifugation and removal of the supernatant, add 2 ml_ of a solution of R123 at 1.5 μΜ, and incubate at +20°C for 5 min, away from the light; - Accumulation of R123 + modulator (inhibitor): add the modulator or an equal volume of DMSO (details in Table 1 below), and incubate at +20°C for 10 min, away from the light; - Rinsings: after centrifugation and removal of the supernatant, add 5 ml_ of iced distilled water; - Reading with the QuantaMaster™ spectrofluorometer, Photon Technology International (PTI), USA. after resuspending the pellet of eggs in 1 ml_ of DW at the temperature of the laboratory (room temperature), incubate at the temperature of the laboratory and away from the light for 60 min, then transfer 900 μΙ to a microcuvette and read on the spectrofluorometer; slit settings: F1 = 11.; F2 = 11.; F4 = 1t. and F3 = 11; λ excitation = 495 nm; λ emission = 525 nm.

[0079] Table 1 - Examples of preparation of solutions for the R123 assay

Table 1

[0080] The potential inhibitors were tested on eggs of sensitive and resistant H. contortus, and their effect was compared with that of sodium orthovanadate (SOV), which has proved to be very effective both against sensitive nematodes and against resistant nematodes (Figure 1). This compound makes it possible to increase the amount of R123 accumulated in the nematodes by 5 times (500% on the ordinate) that found in the absence of inhibitor (100% on the ordinate). Out of all the potential inhibitors given on the abscissa, 7 display a notable modulating effect (ordinate different from 100%, Table 2). Fisetin has a very strong inhibitory effect close to that of sodium orthovanadate against sensitive and resistant nematodes.

[0081 ] Tables 2 and 3 - Accumulation of R123 (% relative to control)

Table 2

[0082]

Table 3

[0083] These results (Figures 2a and 2b and Tables 2 and 3) consequently provide evidence of the existence of a structural difference between the Pgp of nematodes and of vertebrates. These results further demonstrate that fisetin makes it possible to inhibit the P-gp pumps of resistant nematodes more effectively than quercetin when used individually at 50 μΜ. These results allow compositions to be envisaged comprising a nematode P-gp inhibitor which is not quercetin, but which has an at least equivalent efficacy, i.e. antiparasitic compositions including an inhibitor of the nematode P-gp but which has low specificity for the P-gp of the vertebrate to be treated.

[0084] Example 2: larval development tests (LPT) in nematodes [0085] The results obtained for these tests are given in Figures 3a, 3b, 3c and 4. The use of LD50 as an indicator of the efficacy of a given inhibitor/anthelmintic combination does not take into account the maximum effect possibly obtained with higher doses of anthelmintic.

[0086] In the resistant parasites (Figure 4), the fisetin/eprinomectin and myricetin/eprinomectin combinations give the best results; the fisetin/doramectin combination has an effect comparable to that observed for the sensitive parasites.

[0087] Example 3: tests in vivo in lambs infested with resistant H. contortus [0088] 1st test: treatment with doramectin supplemented with subcutaneous injections of fisetin [0089] Protocol [0090] The experiments were conducted on 3-month-old lambs infested with 6000 larvae of the nematode Haemonchus contortus, isolate resistant to the anthelmintics on day 0 (DO). Treatment on D33 with doramectin injectable solution at low doses (from 10 to 30 pg/kg depending on the batch of animals) relative to the manufacturer's recommended dose (of 200 pg/kg for sensitive parasites). Moreover, there is no manufacturer's recommendation for resistant parasites but, on the farm, the doses are above 400 pg/kg, sometimes 600 pg/kg. One animal in two is treated with fisetin administered for 5 days (D33 to D37) by subcutaneous injection and as a supplement. Three doses were tested: 2.5, 5 or 10 mg/kg. The infestation is monitored by coproscopic examinations (counting the eggs emitted by the worms in the faeces) on D54 and by counting the adult worms in the abomasum on D56.

[0091] Results [0092] Reduction in egg count: - no reduction with doramectin alone whatever the dose; - reduction of 64% with the combination of doramectin 20 pg/kg and fisetin at 30 mg/kg (1600 eggs / g versus 4400 eggs / g in untreated controls, Figure 5).

[0093] Reduction in worm count: - doramectin alone 20 pg/kg: reduction of 4%; - doramectin plus fisetin: the most active combination doramectin 20 pg/kg and fisetin 30 mg/kg, with a reduction of 35% relative to the control with doramectin alone (Figure 5).

[0094] This test confirms that in vivo the combination anthelmintic plus inhibitor has an effect, admittedly slight but which is in the same direction as that found by the two in vitro tests (accumulation of rhodamine 123 and "LDT" larval development test). Two hypotheses may explain the low efficacy: - the dose of doramectin is insufficient for resistant parasites, - fisetin administered by subcutaneous injection was poorly absorbed (observation post-slaughter).

[0095] 2nd test: treatment with doramectin supplemented with oral doses of fisetin [0096] Protocol [0097] The experiments were conducted on 3-month-old lambs infested with 6000 larvae of the nematode Haemonchus contortus, isolate resistant to anthelmintics on day 0 (DO). Treatment on D39 with doramectin injectable solution at different doses including the manufacturer's recommended dose (200 pg/kg of live weight of the vertebrate treated), a lower dose (100 pg/kg of live weight of the vertebrate treated), and a dose currently used for treating lambs infected with resistant nematodes (400 pg/kg of live weight of the vertebrate treated) but not recommended by the manufacturer. One animal in two is treated with fisetin administered for 5 days (D39 to D43) by the oral route as supplement at a dose of 30 mg/kg. The infestation is monitored by coproscopic examinations (counting the eggs emitted by the worms in the faeces) on D50 and by counting the adult worms in the abomasum on D53.

[0098] Results [0099] Reduction in the egg count (Figure 6a): - reduction with doramectin alone: 33% at 200 pg/kg and 57% at 400 pg/kg; - reduction with the combination of doramectin and fisetin: 71 % at 100 pg/kg, 73% at 200 pg/kg and 94% at 400 pg/kg.

[0100] Reduction in the worm count (Figures 6b and 6c): - doramectin alone: maximum reduction 66% at a dose of 400 pg/kg; - doramectin plus fisetin: 32% at 100 pg/kg, 50% at 200 pg/kg and 78% at 400 pg.

[0101] These results show that the presence of fisetin makes it possible to reach an efficacy close to 100% with doramectin at the highest dose (400 pg/kg of live weight of the vertebrate treated). The parasite burden could be reduced by nearly 40% with the combination fisetin (administered at 30 mg/kg of live weight of the vertebrate treated in pre- and post-treatment with doramectin) and doramectin (administered at 400 pg/kg of live weight of the vertebrate treated).

[0102] This test can confirm that in vivo the combination of anthelmintic and efflux pump inhibitor (fisetin) has a very significant effect both on the excretion of eggs and on the worm count of an isolate of nematodes very resistant to anthelmintics.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

1. Use of a composition comprising at least one anthelmintic compound and at least one flavone compound, the said flavone compound being chosen among: - a compound of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, and - a morin, provided that the flavone of formula (I) is not quercetin, for preparing a medicinal product that is able to increase the bioavailability of anthelmintics in nematodes; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.
2. Use according to claim 1, in which at least one flavone of formula (I) corresponds to the following formula (II):

in which R1, R2, R3, R4, R5, R6 and R7 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (II) by its anomeric carbon via a glycosidic bond.
3. Use according to claim 2, in which at least one flavone of formula (I) is a flavonol corresponding to the following formula (III):

in which R1, R2, R3, R5 and R7 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (III) by its anomeric carbon via a glycosidic bond.
4. Use according to any one of claims 1 to 3, in which the flavone compound is selected from the group comprising fisetin, myricetin, morin, kaempferol, baicalein and apigenin.
5. Use according to any one of claims 1 to 4, in which the avermectins are selected from ivermectin, eprinomectin, abamectin, doramectin; and the milbemycins are selected from moxidectin.
6. Use according to any one of claims 1 to 5, for use in the treatment or prevention of a parasitosis in a vertebrate, in particular of a nematodiasis, in particular of a haemonchosis.
7. Use according to claim 6, in which the parasitosis involves at least one so-called resistant parasite or at least one so-called susceptible parasite.
8. Use according to any one of claims 6 to 7, in which the vertebrate is selected from the group comprising bovines, caprines (sheep and goats), Equidae, birds and humans.
9. Use according to any one of claims 6 to 8, in which at least one anthelmintic is present in a unit quantity: -from 5 to 10 mg/kg of live weight of the vertebrate to be treated for levamisole, or -from 5 to 600 pg/kg of live weight of the vertebrate to be treated for the macrocyclic lactones, or -from 5 to 300 mg/kg of live weight of the vertebrate to be treated for the benzimidazole derivatives, and at least one flavone of formula (I) is present in a unit quantity from 2.5 to 50 mg/kg of live weight of the vertebrate to be treated.
10. Use according to claim 1, in which at least one anthelmintic compound and at least one flavone compound, the said flavone compound being chosen among: - a flavone of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, - a morin, said flavone of formula (I) being in free form or in the form of a pharmaceutically acceptable salt, and making it possible to increase the bioavailability of the anthelmintic compound by inhibition of glycoprotein P in nematodes, provided that the flavone of formula (I) is not quercetin, are used for administration that is simultaneous, sequential or spread over time.
11. Use according to any one of claims 1 to 10, in which the composition is formulated for oral, parenteral or topical administration.
12. Composition for pharmaceutical or veterinary use comprising at least one anthelmintic compound and at least one flavone, the said flavone being chosen among: - a flavonol corresponding to the following formula (III):

in which R1, R2, R3, R5 and R7 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (III) by its anomeric carbon via a glycosidic bond, and - a morin; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.
13. Composition for pharmaceutical or veterinary use according to claim 12, in which the flavone compound is selected from the group comprising fisetin, myricetin, morin and kaempferol.
14. Composition for pharmaceutical or veterinary use according to any one of claims 12 or 13, in which the avermectins are selected from ivermectin, eprinomectin, abamectin, doramectin; and the milbemycins are selected from moxidectin.
15. Composition for pharmaceutical or veterinary use according to any one of claims 12 to 14, for use in the treatment or prevention of a parasitosis in a vertebrate, in particular of a nematodiasis, in particular of a haemonchosis.
16. Composition for pharmaceutical or veterinary use according to claim 15, in which the parasitosis involves at least one so-called resistant parasite or at least one so-called susceptible parasite.
17. A method of prophylaxis or treatment of parasite infection comprising administering to a subject in need thereof a composition comprising at least one anthelmintic compound and at least one flavone compound, the said flavone compound being chosen among: - a compound of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, and - a morin, provided that the flavone of formula (I) is not quercetin; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.
18. Use of a composition comprising at least one anthelmintic compound and at least one flavone compound, the said flavone compound being chosen among: - a compound of the following formula (I):

in which R1, R2, R3, R4, R5, R6, R7 and R8 represent independently of one another an atom or a group selected from the group consisting of a hydrogen atom, an OH group, a hydroxyl precursor group selected from the group comprising an ester group, an ether group, an alkoxy group, a sulphonate group, a ketone or an aldehyde and a sugar bound to one of the aromatic rings of the flavone of formula (I) by its anomeric carbon via a glycosidic bond, said flavone of formula (I) being in free form or in the form of pharmaceutically acceptable salt, and - a morin, provided that the flavone of formula (I) is not quercetin, for the manufacture of a medicament for the prophylaxis or treatment of parasite infection; in which at least one anthelmintic is selected from the group comprising: levamisole; macrocyclic lactones selected from the group comprising avermectins, or from the group comprising milbemycins; benzimidazole derivatives selected from albendazole, thiabenzole, mebendazole, fenbendazole, oxfendazole, febantel and oxibendazole.
19. Use of a composition of claim 1 substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.
20. A composition according to claim 12 substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.
21. A method of prophylaxis or treatment of parasite infection according to claim 17 substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.