SE465676B - FLAVOL SIGNIFICANT DERIVATIVES, PROVIDED TO MANUFACTURE THIS AND A PHARMACEUTICAL AGENT - Google Patents

Description

465 676 2 10 15 20 25 30 35 40 ./j_\_/°H Ií Ü í / §. / ° \ í / \ / \ OCHB. \ / o \\ // \ f / \ 0 / \ cn on '2 ir / \ / \ OH OH Ä (B) Isosilybin It is clear from these structural formulas that in the case of these compounds they are positional isomers. The compound of formula A is currently designated silibinin in accordance with the INN nomenclature. This term is hereinafter used in the present description for the compound of formula A.

The therapeutic use of silybin caused problems in that silybin is practically insoluble in water, so that silybin-containing injection solutions or preparations in which a certain water solubility is required could not be prepared. DE-PS-1 963 318 does describe silybin derivatives, which show a certain water solubility, but this is a very complex mixture of half-esters of succinic acid. This mixture is just as complex because in the silybin there are four esterifiable hydroxyl groups, and that silybin also contains the two above-mentioned positional isomers and the succinic acid used for the esterification is a dicarboxylic acid, which can form both monoesters and diesters. For pharmaceutical purposes, a product is useless, consisting of an incalculable number of the most diverse, indeterminate compounds.

The object of the invention is therefore to provide water-soluble silicone derivatives suitable for pharmaceutical purposes, which are accurately characterized as chemical individuals.

It has now been found that silibinin derivatives of certain alkane and alkylenedicarboxylic acids meet these requirements.

The invention therefore relates to silibinin derivatives of the general formula I 10 15 20 25 30 3 465 676 // CH 2 -O-CO- (Alk1) n-COOM1 / \ / ° \ OCH3 “° \ ./,_ n \ _ / ° \ / \ / \ 0 / \ / \ / lm »« _____ /. \. . \\ / \ o \ oH ¿H 3 \\ CO- (Alk2) m-COOM2 where n and m are each independently 0 or 1, Alkí and Alkz each independently denote an alkyl residue of 1- 4 carbon atoms, or an alkenylene residue having 2-4 carbon atoms, and M1 and M2 each independently represent a hydrogen atom or an alkali metal atom. Preferred compounds of formula I are compounds in which n and m are each independently 0 or 1, Alk1 and Alkz each represent an alkylene radical having 2 carbon atoms and M and M2 each independently represent an alkali metal atom. Preferably n and m, Alk1 and Alkz as well as M1 and M2 have the same meanings.

Particularly preferred are silibinin C-2 ', 3-dihydrogen succinate, disodium salt.

In the case of the compounds of the invention, the OH groups in the silibinin which are not bound to the abenzene nucleus are partially or completely esterified, for example with oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid or fumaric acid. Preferably, the two non-aromatically bound OH groups in the silibinin are simply esterified with one of the above carboxylic acids.

The process according to the invention for the preparation of the relevant silibinin derivatives is characterized in that approximately 1 part by weight of silibinin of the formula A is dissolved: 4e5 676 4 10 15 20 25 30 35 40 _ /. O H OH / m 7-1, / \\. L / c 2 1 ¿.

I f / Ho \. o å_ _ pä ¿_ R ocn \ /: g \\ _ // \ ~ ._, / \ 0 / __ / 3 I- a f; ” 1 * _.._..... _. / f- «f. 5 'à k.) L x \\ t \\ r //' _ \ oH à fi 3 (A) Silibinin in 1-2 parts by weight of pyridine and with stirring reacts with 1-3 parts by weight of a dicarboxylic acid anhydride of the formula O = C - Alk - C = 0 O / where "Alk" denotes one of the above-mentioned Alk1 and Alká residues, that ethanol is then added until a homogeneous mixture is formed, then water is added slowly under intensive stirring, whereby the present esters of the aromatically bonded OH groups are hydrolyzed, so that as soon as this hydrolysis is complete they are diluted with ethyl acetate, washed with ethyl acetate saturated, acidic water, evaporated the ethyl acetate phase, taken up in ethanol and the residue obtained with an ethanol. alcoholic alkali hydroxide solution to the salt of the free, non-esterified carboxylic acid ester.

Preferably the reaction with the dicarboxylic acid anhydride takes place at 40 ° C.

Advantageously, the pH of the ethyl acetate saturated acidic wash water is maintained at from about 1.5 to 2.4.

These compounds, in particular the compound silibinin-C-2 ', 3-dihydrogen succinate, disodium salt, surprisingly show a pronounced pharmacological effect in the treatment of burns. In addition, despite the described derivatization, they retain the complete pharmacological effect of the known silybin as a liver therapeutic. They are particularly suitable for the treatment of liver cirrhosis and toxic-metabolic liver damage.

In a surprising way, the compounds according to the invention also prove to be extremely active in the treatment of fungal poisonings, especially the very dangerous poisoning caused by insidious fly agaric (Amanita phalloides). Even poisonings caused by halogenated organic solvents, such as chlorotetrachloride, trichlorethylene, chloroform, etc. can also be treated in a surprising manner with good results. In the preventive use, the compounds of the invention prevent the above-described damage.

The invention thus also relates to medicaments which contain these compounds. They are mostly used systemically, for example in the form of pills, capsules, solutions, in conventional carriers and possibly together with common excipients. The daily dose for an adult is approximately 50-500 mg depending on the patient's condition and the severity of the disease symptoms.

Experiments with silibinin-C-2 ', 3-dihydesuccinate, disodium salt (sili-sucan).

The symptoms that occur in burns are caused in particular by an intoxication with products of thermal tissue necrosis. In many different ways it can be proven that autointoxicative processes after severe burns on the skin are responsible for this.

Cross-transplantation of burnt and non-burnt skin on healthy recipient animals and burnt recipient animals, respectively, is particularly convincing, as it turns out that the non-burnt recipients of burnt skin perish while burnt recipients of healthy skin do not recognize any harmful effects; compare K H Schmidt et al, "Newer aspects of autointoxication after severe burns"; "Die Verbrennungskrankheit" G'W2 & me flfl d et al, eds L), Springer, Berlin 1982, pp 45-52.

In the event of burns on the skin, a number of chemical compounds are released or newly formed. Despite their diversity, they have succeeded in explaining the structure of some of these associations.

It could be shown, among other things, that the compounds formed in the case of burns on the skin show similarities to such compounds which are formed during lipid peroxidation. There are also analogies regarding the toxic effects of these substances. Particularly striking is the formation of toxic-acting saturated and unsaturated aldehydes of different chain lengths as a result of lipid peroxidation (Benedetti et al., "Identification of 4-hydroxynonenal as a cytotoxic product originating from the peroxidation of liver microsomal lipids", Biochim Biophys Acta, 620, 281-296, 1980) and the thermal tissue damage (KH Schmidt et al "Studies on the structure and biological effects of pyrotoxins purified from burned skin", World J Surg, 3, 361-365, 1979). It is assumed 465 676 , 6 10 15 20 25 30 35 40 because burns lead to an oxidative damage of cell structures.

Thus, autoxidative changes regarding membrane lipids as a result of an autointoxication after severe burns were investigated. In particular, changes in the fatty acid composition of the membrane lipids were investigated. Furthermore, the extent to which the silibinin derivatives according to the invention affect the changes in the fatty acid composition of the membrane lipids was tested.

Changes in the fatty acid composition of membrane lipids after severe burns.

Male and Wistar rats with an average weight of 360 g were kept in groups of 3 each with free access to water and dry food. Until the beginning of the experiment, the room temperature was 22 ° C and after the beginning of the experiment, the animals were kept at 30 ° C.

The burns on the skin were obtained by means of a copper stamp with a surface of 20 cm 2 at constant pressure and a temperature of 250 ° C. To avoid thermal damage to deeper organs, the skin was placed on an air-cooled, halved spatula. With this animal model M fl, very precise burns are achieved, which give constant survival values.

Before the start of the experiment, the animals received an anesthetic with 50 mg / kg nembutal. Following the skin burn, 20 ml of Ringer lactate solution was injected intraperitoneally for shock prophylaxis.

Five experimental groups were formed: a) Nonmal group, completely unharmed animals b) Chemical group I: silibinin treatment for 6 days only with 75.5 mg of silica. c) Control group II: sham-operated animals d) Grm¶> ned1nänn- ä fi mbdec fi urz e) Test group: 25%, 2so ° c, 20 sec, 0.5 at. animals which received 75.5 mg of silica-sucra intraperitoneally for 6 days, starting one day before the burning of the skin.

To isolate the microsomes, the animals were bled under anesthesia at the end of the experimental period. The liver was then removed, weighed and immediately transferred to ice-cold isolation medium (0.25 m sucrose, 1 mM EDTA, 10 mmol tris-HCl, pH 7.2). The liver was cut into pieces and homogenized in the medium. By differential centrifugation, the microsome fraction was pelletized. The microsomes were resuspended and centrifuged again. Then a suspension was prepared, in which 1 ml of suspension corresponded to 1 g of liver tissue.

The lipids were determined by the method according to J Folch ("A rapid method for the isolation and purification of total lipids from animal tissues", J Biol Chem, 226, 497-508 (1957)), modified by Bligh and Dyer ("A rapid method of total lipid extraction and purification ", Can J Biochem Physiol, 37, 911-917 (1959)).

The extracted microsome lipids were saponified with sodium hydroxide solution. The free fatty acids were esterified by the addition of BF3-methanol. After evaporation of the methanol and removal of hydrophilic by-products, the fatty acid esters were determined quantitatively.

In the case of the groups of animals without burns, no significant change in the fatty acid pattern could be determined. The anesthesia and the small surgical procedure thus do not lead to any change in the microsomal lipids. For this reason, for the further comparison, the normal group and the control group were merged into a single control group.

A comparison between the animals without burns and the animals with burns regarding their microsomal fatty acid pattern showed strong shifts from unsaturated to saturated fatty acids.

In the accompanying drawing, Fig. 1 shows the fatty acid distribution in the microsomal liver lipids and the changes caused by heat damage to the skin. The proportion of palmitic acid (C16) increases after the burn received from 25.1 to 34.4% of the total fatty acids.

In the case of stearic acid (C18), the proportion in the case of the burn-injured animals is 46.3%, which is 13.2% higher than the value obtained in the case of the control animals. In the case of oleic acid (C18fU, a slight, non-significant decrease is detectable. The proportion of linoleic acid (C18: 2) decreased after about burns to about 1/3 of the initial value. In the case of arachidonic acid (C20: 4) finally amounted to obtained burns content to only 31% of the initial content.

The following Table 1 shows the effect of the silicas on the fatty acid content of the animals with and without burns. 465 676 8 10 15 20 25 30 35 40 TABLE 1 Fatty acid pattern for the microsomal lipids from rat liver after silica-sucrone therapy in cases of animals with burns and animals without burns.

C 16 C18 CT8: 1 C18: 2 C20: 4 Without burns 29.8% 37.2% 8.9% 9.6% 16.2% (conf. Roll group I) 16.2 112.3 11.1 23.3 14.9 With burns 25.4% 37.5% 7.8% 11.4% 18.0% t6, o 18.6 21.0 ïs, 3: 9.1 It turns out that the treatment according to the invention with a silibinin derivative in the case of the control animals without burns did not cause any significant changes in comparison with the untreated animals. In the case of animals with burns leads. therapy to completely eliminate the loss of unsaturated fatty acids.

In summary, the following can be stated: burns lead to changes in the fatty acid pattern of microsomal lipids. It is assumed that this may be due to an oxidative damage to the membranes. This is especially evident by the sharp decrease in the polyunsaturated fatty acids.

The silibinin derivatives used according to the invention are now capable of inhibiting oxidative cell damage. They are therefore particularly suitable for disrupting oxidative damage mechanisms after severe burns.

As already mentioned, it is assumed that autotoxic reactions after severe burns lead in particular to oxidative cell damage. It was therefore investigated what effect a standardized heat injury has on the PHA-induced blastogenesis of T lymphocytes from the spleen and the peripheral blood from rats. It was further investigated how the silibinin derivatives useful according to the invention affect such lymphocytic dysfunctions after severe burns.

Effect of a standardized heat injury on the PHA-induced blastogenesis of T lymphocytes from the spleen and peripheral blood of rats.

In the manner described above, burns to the back of rats of the Wistar strain are caused by means of a copper stamp. Apparently burned animals served as a control group, on which all operative manipulations were carried out without these being burnt.

After 2, 4, 7 and 9 days, blood and spleen were removed under ether anesthesia I) 10 15 20 25 30 35 40 9 465 676 from the animal showing burns and the control animals, respectively.

Heparinized blood was layered to isolate the lymphocytes on Ficoll-Hypague solution (density 1,077). Centrifugation was then performed and the resulting lymphocytes were tested with trypan blue for their vitality. For the isolation of the splenic lymphocytes, the organ was disintegrated, passed through a sieve and freed from the accompanying erythrocytes by means of a lysing solution according to Gay.

Thereafter, the cell mixture was incubated in a vessel in the presence of 5% heat-inactivated fetal calf serum for 30 minutes to reduce (5%) the proportion of mononuclear cells in the suspension by adhering to the vessel wall. For the culture, the cells were introduced into "flat-bottomed" microtiter plates. Then 20% fetal calf serum was added. In this way, the spontaneous blastogenesis was determined by measuring the incorporation of 3 H-thymidine (2 Ci / mM) into the cells' DNA. It is clear that an optimal mitogen stimulation takes place at a PHA concentration (mitogen-phytemagglutinin) of 5 pg / ml. In these attempts to optimize the cellular test system, it was further determined that the maximum stimulation of new synthesis of DNA takes place after 72 hours. that the optimal concentration of fetal calf serum is at 20% to achieve the highest stimulation.

As described above, spontaneous blastogenesis was determined by measuring the incorporation of 3 H-thymidine into the cells' DNA.

The cells were harvested 18 hours after the addition of 3 H-thymidine, the zero point for the said 18 hours coinciding with the time of the maximum stimulation.

To investigate the effect of the silibinin derivatives useful according to the invention, a group of rats was treated with a silibinin derivative. For this purpose, 75.5 mg of silicone were injected intraperitoneally once daily. This therapy was carried out from the day on which the burns were inflicted to the day on which the above-mentioned organs were removed (maximum up to the ninth day).

For the evaluation of the results obtained in the case of the control animals and the animals without burns and the animals treated with silica, the stimulation index was determined. This number is the ratio of the mean value of the stimulated sample and the mean value of the control sample. Based on the stimulation index thus obtained for each experimental animal, an average stimulation index per group of animals was calculated 465 676 10 10 15 20 25 30 35 40. The results obtained are expressed by this index SI.

In the accompanying drawing, Fig. 2 shows the effect of the silica-derivative used on the blastogenesis of lymphocytes. In the case of the burn-injured animals, the reduced stimulation of the cells by silibinin clearly increased.

Already on the second day, in the case of the silica-treated animals, an approximately ten times higher response of the blood lymphocytes to PHA was shown. On the fourth day after receiving burns, the value of stimulation index in the case of blood lymphocytes for treated animals amounted to 8, while the corresponding value in the case of the untreated animals amounts to 1.5 »In the case of spleen cells, the stimulation index of the burnt, untreated animals is all clearly below 1. The administration of silibinin leads to a marked improvement during all examined days, with a maximum value appearing on the seventh day after the burns received.

Comparative experiments were also performed, which showed that silica alone in the case of healthy animals does not lead to any significant changes in the stimulation ability of the PHA-induced blastogenesis of T lymphocytes from the spleen and from peripheral blood.

Thus, the silinine used according to the invention significantly stimulates the blastogenesis of lymphocytes in burnt animals.

It was further established that in the case of the animals treated with the silibinin derivatives the general catabolism was less, since the animals rapidly gained weight again after the heat injury.

§Yê @ Bɧš¶iÉÉQi§9êE = Poisoning due to insidious fly agaric is one of the most severe, which exists in medicine. Although only 10-30% of all fungal poisonings are caused by the green, insidious fly agaric, the poisoning with it attracts fungi due to their danger since time immemorial greatest medical interest.

In older literature, mortality was reported at 30-50%. Thanks to modern intensive care, according to a combined study by Floersheim et al with 205 patients, this number has been reduced to an average of 22.4%.

The poison in the insidious fly agaric, amanitin, can already be lethal at a dose of 7 mg for an adult human. This amount of toxin is contained in approximately 50 g of a fresh mushroom specimen.

After a series of promising animal experiments with regard to the results, the active compound sili-sucna was incorporated into the therapy for fungal poisoning caused by insidious fly agaric. In addition to the usual therapeutic measures, 28 patients with poisoning caused by insidious fly agaric were also treated with silicone. Of these 28 patients, only one died, ingesting large amounts of the fungus in order to kill itself. This result shows a huge therapeutic progress in this area.

A suspension of 500 g of the product according to DE-AS-1 923 082, column 8, lines 14-19, with a silymarin content of about 70% at an isomer ratio silybin / silidianin / silicristin of about 3: 1: 1, the silybin containing about 1/3 isosilybin, and 2 kg of methanol ë ”2.53 l are heated with stirring for 15 minutes to boiling. From the solution thus obtained, some silibinin may then already precipitate. Then 0.75-1.25 kg E is evaporated in vacuo 0.96 - 1.58 l methanol and the residue is left at room temperature for 10-28 days. The precipitated silibinin is filtered and washed twice with 50 ml of cold methanol each. After drying at 40 ° C in vacuo, the isolated crude silibinin is purified as follows: 60 g of crude silibinin are dissolved in 3 l of technical acetic acid ester under heating; then 20 g of activated carbon are added and stirring is carried out for a further 2 hours under reflux conditions.

Then clear filtration is carried out and the solution is evaporated at SOOC under reduced pressure to about 250 ml. The concentrate is stirred for 15 minutes using an ultra-Turrax apparatus and charged with 25 ml of methanol. The mixture is then allowed to stand overnight at room temperature. Before the filtration of the precipitate thus precipitated, the mixture is again stirred for 5 minutes also by means of an ultra-Turrax apparatus. The filtered precipitate is washed twice with 50 ml of acetic acid ester and dried in a vacuum drying cabinet overnight at 40 ° C. Finally, the product is ground and dried under the same conditions for 48 hours.

EXAMPLE 1 Preparation of silibinin-C-2 ', Bed hydrogen hydrogen succinate 10 -o-co-cH -cH2-coon J / O \; / CH2 2 H g yr] / OCHB g g l 01.

50 g of silibinin are dissolved at 45 ° C in 70 ml of pyridine, 50 g of succinic anhydride are added, the mixture is stirred for about 8 hours at 45 ° C. add 30 ml of ethanol and stir until a homogeneous mixture is formed. Then 60 ml of water are added within about 30 minutes with vigorous stirring to digest phenyl esters.

After about 1 hour of stirring at 30 ° C, the phenyl esters are quantitatively hydrolyzed. The completeness of the hydrolysis is tested by HDLC. The hydrolysis is stopped by rapidly adding 1.7 l of acetic acid ethyl ester to the reaction mixture obtained.

To separate excess succinic acid and pyridine, the reaction solution diluted with acetic acid ethyl ester is extracted twice with 5 l of water each, which is saturated with ethyl acetate and exhibits a pH of 1.85 (adjusted with dilute aqueous hydrochloric acid). in countercurrent. The acetic acid ethyl ester saturated with acidic acid is circulated to the dilute reaction solution and finally, by adding dilute hydrochloric acid, the pH is maintained at 1.85 until this pH remains constant after the passage of acetic acid ethyl ester.

The acetic acid ethyl ester phase is then extracted to wash out excess hydrochloric acid twice in countercurrent with 3.4 l of water each, which is saturated with ethyl acetate. As soon as the pH of the wash water is higher than 4.5, the organic phase is separated quantitatively, evaporated at 40 DEG-50 DEG C. in vacuo to 1/12 of the starting volume (approximately 0.2 L) and diluted with 1.25 ml of ethanol. .

The title compound is obtained by eluting with ethanol / water and drying at 50 ° C in vacuo for 15 hours.

To prepare an analytical sample, the title compound is recovered three times from ethanol / water and then dried for 15 hours at 5000 in vacuo. 10 15 20 25 30 35 40 13 465 676 In the FD mass spectrum, the molecular peak appears at the expected molecular weight of 682.

The IR spectrum shows in the range of the CO valence frequency two overlapping bands, one of which, as is also the case for silibinin, is to be assigned to the carbonyl group in the pyrone ring at the wavelength of 1 635 cm -1. The second band is at 1 730 cm-1 and originates from the two ester carbonyl groups. The 1 H-NMR spectrum confirms that a double esterification has taken place. Thus, the ratio obtained by integration between aromatic protons and methylene protons in the succinic acid residue amounts to 8: 8 (ppm range 5.9 - 7.1). The ratio of these methylene protons (ppm 2.6) to the methyl protons in the methoxy group (Ppm 3.8) amounts to 8: 3 and thus corresponds accordingly. The chemical shifts at 13 also show that the esterification at the two alcoholic OH groups has taken place, because the chemical shifts change most strongly at C11 and the nearest carbon atoms C12-C14 as well as in the C2-C C studies Elemental analysis for C33H30O16 (682 , 60): CHO Calculated: 58.07 4.43 37.50 Found: 58.05 4.57 37.31 EXAMPLE 2 Preparation of silibinin-C-2 ', 3-dihydrogen succinate, disodium salt.

CH -0-CO-CH -CH -CONa T / _'_ \ l / ° \ / 2 2 2 / \ ___ I u // O __ /, / í ~ \\ o / _a \\ (/ OCH3 I, 9 lm \ N / \ oH \ co-cH2-cH2-coNa To the ethanol solution obtained according to Example 1 for - A - - -r dnxmann fl nl flfl er fi m fi à ïng and cooling from outside at -SOC to 9 ° C a on the basis of a determination of the solids content of this solution calculated amount of a 6% ethanolic sodium hydroxide solution, stir the suspension for another hour at room temperature, separate the precipitated beige solids while applying a suction, 465 676 '4 10 15 20 25 suspend this twice for 5-10 minutes using a Turrax stirrer in 150 ml of ethanol and reapply a suction, then remove the product for 14 hours at room temperature in 280 ml of ethanol to remove residual acetic acid ethyl ester. , reapply a suction, wash with 70 ml of ethanol e and dry for 15 hours at 40-45 ° C in a vacuum drying cabinet, then 5.1 grind the pre-dried product, aim for a smaller grain size than 0.2 mm and dries for another 48 hours at 40-4500 in vacuum. In this way 52 g of the title compound are obtained (69% yield).

The compound mentioned in the title above has no sharp melting point. It begins to sinter at about 80 ° C and melts to form blisters at about 100 ° C. x = 288 nm, e = 1.73 x 104.

The molecular weight of the above compound is 726.56. The compound is the UV spectrum in methanol shows; Åma a light beige, microcrystalline powder without specific odor and with a salty taste. It is readily soluble in water, sparingly soluble in ethanol and practically insoluble in acetone, ether and chloroform. êazëaëaiaaëeëeæesl Preparation of lyophilisate for intravenous administration.

Silibinin-C-2 ', 3-dihydrogen succinate, disodium salt 75.0 mg Mannit 10.0 mg Water for injections To 1.5 ml of 1.5 ml solution is filled into tip ampoules with a volume of 5 ml and then lyophilized according to known techniques. The ampoules with the finished lyophilisate are closed for storage in the usual way.

Before use, the lyophilisate is dissolved in 5 ml of sterile, physiological saline solution to form a clear solution.

Claims (8)

Ü 465 676 PATENTKRAV Silibinin derivatives of the general formula I / Ow / Hz -o-co- (A1k1) n-cooM1 1 (I) o \ co- (A11 <2) m-cooM2 where n and m are each independently 0 or 1, Alk 1 and Alk 2 each independently represent an alkylene radical having 1 to 4 carbon atoms or an alkenylene radical having 2 to 4 carbon atoms and M 1 and M 2 each independently represent a hydrogen atom or an alkali metal atom. Silibinin derivatives according to claim 1, characterized in that n and m each independently represent 0 or 1, Alk1 and Alkz each represent an alkylene radical having 2 carbon atoms and M1 and M2 each independently represent an alkali metal atom. . Silibin derivatives according to Claim 1, characterized in that n and m, Alkí and Ålkz and M1 and M2 have the same meanings. Silibinin derivative according to any one of claims 1-3, characterized in that it consists of silibinin-C-2 ', 3-dihydrogen succinate, disodium salt of the formula: HO íššâššï // Û \\ í // CH2- O * CO-CH2-CH2_COONä \ / \ lß \ 5G- JG: \\\ ¥ // // V if; \ co-cH2 -cnz -cooNa I OH 465 676 _ 16 5. A process for the preparation of silibinin derivatives according to claims 1 to 4, characterized in that a part by weight of silibinin of the formula A is dissolved: CH 2 OH / _ 2 / O 2 C) Û \ \. (H) Silibinin in 1-2 parts by weight of pyridine and reacting with stirring with 1-3 parts by weight of a dicarboxylic acid anhydride of the formula: o = c-A1k- = o O where "Alk" denotes an Alk1 or Alk2 residue according to claim 1, then add ethanol until a homogeneous mixture is formed, then slowly add water with vigorous stirring, the present esters of the aromatically bonded OH groups being hydrolyzed, so that as soon as this hydrolysis is complete dilute with ethyl acetate, wash with ethyl acetate saturated acidic water; evaporates the ethyl acetate phase, takes up ethanol and transfers with an alcoholic alkali hydroxide solution the product obtained to the salt of the free carboxylic acid ester. 6. A process according to claim 5, characterized in that the reaction with the dicarboxylic anhydride is carried out at about 40-50 ° C. A process according to claim 5, characterized in that the ethyl acetate saturated acidic wash water is maintained at a pH of about 1.5 - 2.4. Pharmaceutical composition containing as active ingredient at least one compound according to any one of claims 1-4, optionally in a pharmaceutical carrier or excipient.