JPH0432073B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL FIELD OF APPLICATION The present invention relates to a novel flavolignan derivative, a process for its preparation, and a pharmaceutical composition containing this novel compound. Conventional technology silybum marianum (L.)
Gaertn. (Carduns Marianus L.) is a conventionally known medicinal plant. From the frapolignan produced in the fruit of this plant, R. Muenster isolated a component called silybin.
1966, see]. The structure of this compound was elucidated by A. Pelter and R. Haensel [Tetrahedron Letters, London 25 , 2911-
2916/1968]. Silybin, formerly known as silymarin, is a useful liver treatment substance [West German patent no.
1767666]. An industrial method for producing silybin (silymarin) is described, for example, in West DE 1923082. In 1974, H. Wagner, P. Diesel and M. Seitz postulated two positional isomers for silybin: silybin and isosilybin [Arzneimittelforschung]. ) 24 (4)466~
471]. This conjecture was experimentally investigated and confirmed by A. Arnone, L. Merlini and Z. Zanarotti [Journal of the Chemical Society Chemical Communications] (J.Chem.
Soc.Chem.Comn.) 16 , 696-697/1079].
According to this, the known silybin consists of two different compounds, namely compounds of the following structural formulas A and B: This structure shows that these compounds are positional isomers. Compounds of formula A have recently been
Silibinin was given in the INN naming. This name is used herein for compounds of formula A. The therapeutic use of silybin has led to the difficulty that this silybin is practically insoluble in water, so that silybin-containing injectable solutions or formulations (in which case a certain water solubility is required) cannot be produced.
DE 1963318 describes silybin derivatives which apparently have a certain water solubility, but these are very complex mixtures of half-esters of succinic acid. This mixture has five esterifiable hydroxyl groups in silybin, which also has the two positional isomers mentioned above, and the succinic acid used for esterification is not only a monoester but also a diester. It is complex because it is a dicarboxylic acid that can also form . Products consisting of very different, unexplained and unpredictable compounds cannot be used for pharmaceutical purposes. PROBLEM TO BE SOLVED BY THE INVENTION The object of the invention is therefore to obtain water-soluble silibinin derivatives which are suitable for pharmaceutical purposes and which are precisely chemically specified as individual compounds. Means of Solving the Problem Certain silibinin derivatives of alkanes and alkylene dicarboxylic acids have been found to meet this requirement. Therefore, according to the invention, the general formula: [In the formula, m represents 1, Alk ₁ represents an alkylene group having up to 4 carbon atoms or an alkenylene group having 2 to 4 carbon atoms, and M ₁ represents a hydrogen atom or an alkali metal atom] A silibinin derivative is obtained. Advantageous compounds of the general formula () in which m is l
, Alk ₁ represents an alkylene group each having 2 C atoms, and M ₁ represents an alkali metal. Particular preference is given to the disodium salt of silibinin-C-2',3-dihydrogensuccinate. In the compounds according to the invention, the hydroxyl groups which are not bonded to the benzene nucleus are partially or completely esterified, for example with oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid or fumaric acid. Advantageously, the two non-aromatic bonding hydroxyl groups of silibinin are simply esterified with one of the aforementioned carboxylic acids. The present invention provides a method for producing a novel compound of the general formula (), wherein silibinin of the formula (A) has about 1
Part by weight is dissolved in 1 to 2 parts by weight of pyridine and mixed with the general formula: React with 1 to 3 parts by weight of dicarboxylic acid anhydride [where Alk represents one of the same definitions of Alk ₁ above], then add ethanol until a homogeneous mixture is obtained, followed by vigorous stirring of this and water. As soon as this hydrolysis is completed, the reaction mixture is diluted with ethyl acetate, washed with acidic water saturated with ethyl acetate, and the ester containing an aromatically bonded hydraloxyl group is hydrolyzed. The ethyl phase is evaporated, the residue is taken up in ethanol and converted into the salt of this free unesterified carboxylic acid residue with an alcoholic solution of alkali metal hydroxide. The reaction with this dicarboxylic acid anhydride is carried out at 40-50℃.
It is advantageous to carry out the Advantageously, the pH of the ethyl acetate saturated acidic water is maintained at about 1.5 to 2.4. These compounds, especially the disodium salt of silibinin-C-2',3-dihydrogensuccinate, surprisingly exhibit excellent pharmacological action in the treatment of burns.
Moreover, despite said derivatives, they retain the full pharmacological effect of the known silybin as a liver therapeutic agent. They are particularly suitable for the treatment of liver cirrhosis and toxic-metabolic liver disorders. Changes in fatty acid types in liver microlipids play an important role both in the case of burns and in cases of liver poisoning and liver lesions. Therefore, changes in fatty acid type are a measure of burns and poisoning and liver damage. Changes in fatty acid types in liver microsomal lipids due to these disorders can be reversed with the silibinin derivatives of the present invention. Surprisingly, the compounds of the present invention are useful for mushroom toxins, especially
It has also proven to be extremely effective in treating the highly dangerous poison caused by the mushroom known as Amanita phalloides. Poisons caused by halogenated organic solvents, such as carbon tetrachloride, trichlorethylene, chloroform and the like, can also be treated with surprising success here. In the case of prophylactic use, the compounds according to the invention prevent said disorders. The invention therefore also provides pharmaceutical compositions containing at least one of these novel compounds together with a pharmaceutically acceptable solid or liquid diluent or carrier agent. They are usually used systematically, for example in the form of pills, capsules, solutions and the like, in customary carriers and optionally together with customary adjuvants. The daily dosage for adults is approximately 50-500 mg, depending on the patient's condition and the severity of the disease. Experiments with the disodium salt of silibinin-C-2', 3-dihydrogen succinate (Sili-Suc-Na) Symptoms in the case of burns were caused by intoxication, in particular by the formation of thermal tissue gangrene. The demonstration that autotoxicity is the response after severe skin burns was carried out in various ways. In particular, it is plausible to cross-transplant burn and non-burn skin into healthy and burn recipient animals, in which the non-burn receptors in the burn skin die and the burn receptors in the non-burn skin become damaged. It has been shown that there is no effect [KH Schmidt's New Aspects of
Autointoxication After Severe Burnings (New aspects of
autointoxication after severe burnings): the
The burning daisies
disease); see F. W. Ahnefeld et al., Springer Verlag, Berlin, pp. 45-52]. In the case of skin burns, the development or neoplasia of many compounds occurs. Instead of many of these, it has been possible to describe the structures of some of these compounds. In particular, the compounds produced in the case of skin burns are similar to those produced during lipid peroxidation. The toxic effects of these substances are also similar. In particular, saturated or unsaturated aldehydes of various chain lengths have been shown to cause toxic effects due to lipid peroxidation [Identification of 4-hydroxynonenal by Benedetti et al.
Identification of 4-hydroxynonenal as a cytotoxic product originating from the liver microsomal lipids (Identification of 4-hydroxynonenal as a
cytotoxic product originating from the
peroxidation of liver microsomal Lipids), Biochim.
Biophys. Acta) 620 , pp. 281-296 (1980)] and thermal tissue damage [KH Schmidt.
Studies on the Structure by et al.
Studies on the etructure and biological effects of pyrotoxins from burned skin
biological effects of pyrotoxins purified from
burned skin）World J.Surge・（World J.
Surg.) 3 , pp. 361-365 (1979)] are particularly impressive. Therefore, burn injuries are hypothesized to result in oxidative damage to cellular structures. Therefore, autooxidative changes in membrane lipids were studied as a consequence of autotoxicity after severe burn injury. In particular, we investigated changes in the fatty acid composition of membrane lipids. Furthermore, it was tested to what extent the silybin derivatives according to the invention affect changes in the fatty acid composition of membrane lipids. Changes in fatty acid composition of membrane lipids after severe burn injury. Male Wistar rat (average weight 360 g)
rats) were kept in three groups with free access to water and dry food. By the start of this experiment, the room temperature was 22°C and the animals were kept at 30°C after the start of this experiment. Using a copper stamp with a surface area of 20 cm ² , constant pressure and
A skin burn was formed at a temperature of 250°C. The skin was drawn onto an air-cooled hollow spatula (epatula) to avoid thermal damage to deep tissues. Highly precise burns can be created in this animal model with consistent survival rates. Before the start of this experiment, animals were anesthetized with nembutal 50 mg/Kg. After the burn,
20 ml of Ringer lactate was injected intraperitoneally to prevent shock. Five experimental groups were used: (a) Normal group: completely intact animals (b) Control group: silibinin treatment alone for 6 days with 75.5 mg of Sili-Suc-Na (c) Control group: treated animals ( d) Burn animal group: 25%, 250°C, 20 seconds, 0.5 at. (e) Test group: Sili-Suc starting from 1 day after burn.
- Animals with 75.5 mg of Na applied intraperitoneally for 6 days. For the isolation of microsomes, the animals were bled under anesthesia at the end of the experimental period. Subsequently, the liver was removed, weighed, and immediately placed in ice-cold isolation medium (0.25M sutucarose, 1mM EDTA, Tris.
10 mmol of HCl, pH 7.2). Livers were cut and homogenized in medium. The microsomal fraction was pelleted by differential centrifugation. Resuspend the microsomes,
Centrifuged again. Subsequently, a suspension was prepared, in which 1 ml of suspension corresponded to 1 g of liver tissue. Lipids were measured by the method of J. Folch [A Simple Method for Isolation and Pourification].
A simple method for the
isolation and purification of total lipids
from animal tissues), Journal of Biological Chemistry (J.biol.Chem.) 226 ,
497-508/1957 Modification of Bligh and Dyer; A rapid method of total lipid extraction and distillation
method of total lipid extraction and
purification), Canadian Journal of Biochemistry and Physiology (Can.J.Biochem.physiol.) 37 , 911-917/1959
Reference] The extracted microsomal lipids were saponified with an aqueous sodium hydroxide solution. Free fatty acids were esterified by addition of _BF3 -methanol. After evaporation of methanol and removal of hydrophilic by-products, fatty acid esters were determined quantitatively. In the case of the non-burned animal group, no notable changes in fatty acid types could be ascertained. Therefore,
Anesthesia and slight procedural manipulations did not alter microsomal lipids. For this reason, the normal and control groups were combined into one control group for comparison. Comparison of non-burned and burned animals with respect to their microsomal fatty acid types did not show a significant conversion of unsaturated to saturated fatty acids. The accompanying Figure 1 shows fatty acid distribution in microsomal liver lipids and changes due to thermal skin injury. The proportion of palmitic acid (c16) is
Increased from 25.1 to 34.4% of total fatty acids. For steering acid (C18), the proportion in burnt animals was 46.3%, which was 13.2% higher than the value obtained in control animals. In the case of oleic acid (C18:1) a slight and insignificant decrease is observed. The proportion of linoleic acid (C18:2) decreased to about one-third of its initial value after burn injury. Finally, in the case of arachidonic acid (C20:4), 31% of the initial value after burns
It was recognized that only. The following table shows the effect of Sili-Suc-Na on the proportion of fatty acids in burned and non-burned animals:

[Table] Treatment with silibinin derivatives according to the present invention
It can be seen that no significant changes occur in the case of non-burned control animals compared to untreated animals. In the case of burnt animals, treatment completely eliminated the loss of unsaturated fatty acids. In summary, the following can be said: Burn injury alters the fatty acid type of microsomal lipids. This seems to be due to oxidative damage to the film. This is especially
This is evident by the significant reduction in polyunsaturated fatty acids. Therefore, the silibinin derivative according to the invention is able to prevent oxidative cell damage. Therefore,
These are particularly useful for inhibiting oxidative damage mechanisms after severe burns. As mentioned above, autotoxic reactions after severe burns are believed to result in particular oxidative cell damage. We therefore investigated the effect of standard thermal trauma on PHA-induced cell division of T-lymphocytes from rat spleen and immature blood. Furthermore, the effects of the silibinin derivative according to the present invention on lymphocytic function disturbance after severe burn injury were investigated. T-cells from rat spleen and peripheral blood
Effect of standard thermal trauma on PHA-induced blastogenesis The dorsal skin of Wistar rats was burned using a copper stamp in the manner described above. As a control group, sham-burned animals were used that underwent all treatment maneuvers but were not burned. 2 from burned and non-burned animals;
Blood was collected after 4, 7, and 9 days, and the spleen was removed under ether anesthesia. For lymphocyte isolation, heparinized blood was mixed with Ficoll-Hypaque solution.
solution: specific gravity 1.077). This was subsequently centrifuged and the lymphocytes obtained were tested for their vitality using tryptan blue. For isolation of splenic lymphocytes, the tissue was minced and passed through a sieve.
Associated red blood cells were removed using Gay's lysis solution. This cell mixture was subsequently incubated in a container for 30 minutes in the presence of 5% heat-inactivated fetal bovine serum to reduce the proportion of single cells in the suspension (5%) due to attachment to the container walls. . For calculations, cells were placed into flat bottom microtiter plates. then 20
% fetal bovine serum was introduced. In this way, natural cell division induces ³ H-thiidine into the DNA of this cell.
(2Ci/mM) was measured. In previous experiments, the optimal mitogenic stimulation was 5 μmg/ml.
It was obvious that this would occur when the PHA concentration (mitogen phytohema glutinin) was In the case of this experiment for the optimization of this cell test system,
It was confirmed that the maximum stimulation of de novo DNA synthesis occurred after 72 hours. Furthermore, it was determined that the optimal concentration of fetal bovine serum to achieve maximum stimulation was 20%. As mentioned above, natural cell division was measured by introducing ³ H-thymidine into the DNA of the cells.
Cells were collected 18 hours after addition of ³ H-thymidine, with the 0 point for this 18 hour period coinciding with the time of maximal stimulation. To investigate the effect of the silibinin derivative according to the invention, a group of rats were treated with the silibinin derivative. For this purpose, 75.5 mg of sili-cus-Na was injected intraperitoneally once a day. This treatment was carried out from the day of the burn until the day the tissue was removed (up to 9 days). The irritation index was calculated for the evaluation of the results obtained with control animals and with sili-suc-Na treated animals. This number represents the quotient of the mean value of the stimulus sample and the mean value of the control sample. From the irritation index thus obtained for each experimental animal, the average irritation index for each group of animals was calculated. The obtained results are expressed as an index SI. The accompanying Figure 2 shows the effect of the use of sili-suc-Na on cell division of lymphocytes. In the case of burnt animals, the reduced stimulatory capacity of cells was significantly increased by silibinin derivatives. Already on the second day in the case of sili-suc-Na treated animals, the response of blood lymphocytes to PHA was found to be approximately 10 times higher. On the fourth day of trauma treatment, the stimulation index value for blood lymphocytes for treated animals was 8.
and the corresponding value for untreated animals was 1.5. In the case of the spleen, the irritation indices of all burned untreated animals were clearly below 1. The application of silibinin derivatives was significantly improved on all study days, with the maximum being observed on the 7th day of trauma treatment. Comparative experiments were also conducted showing that in healthy animals, sili-suc-Na alone produced no significant changes in the ability to stimulate PHA-induced cell division of T-lymphocytes from the spleen and peripheral blood. did. The silibinin derivatives according to the invention therefore significantly stimulate cell division of lymphocytes in burnt animals. It was also established that in the case of the animals treated with the silibinin derivatives according to the invention, the general catabolism was low, since after the thermal trauma the animals quickly gained weight again. Poisonous Mushrooms Poisonous Mushrooms (Amanita Amanita)
phalloides) poisons are among the most medically serious. 10-30% of all mushroom poisonings are caused by Amanita muscariae, which has always been of great medical interest because of its danger. In old literature, the mortality rate was 30
It is said to be ~50%. With modern progressive medicine, this value has been reduced to an average of 22.4%, according to a study collected by Floersheim et al. in 205 patients. The poison amanitin from Amanita muscaria can be fatal to adults in amounts of 7 mg (this toxic amount is present in about 50 g of this raw mushroom). After a series of successful animal experiments, the active substance sili-suc-Na was used in the treatment of poisoning by Amanita muscaria. Twenty-five patients with Amanita muscariae poisoning were treated with sili-suc-Na in addition to conventional treatment.
Of these 28 patients, only one person died after ingesting a relatively large amount of this mushroom for suicidal purposes. This result represented a significant therapeutic advance in this field. Silibinin dihemisuccinate (silibinin-C-
The LD ₅₀ of 2',3-dihydrogen succinate, disodium salt) was >1000 mg/Kg (intravenously). Production of isosilybin-free silybinin According to West German Patent No. 1923082, the silymarin content is about 70% and the isomer ratio of silybin/silydianin/silycristin is about 3:1:1, and the silybin content is about one third of that of isosilybin. a product
A suspension of 500 g in 2 kg (approximately 2.53 g) of methanol is heated and boiled for 15 minutes while stirring. After this time, some silibinin can precipitate out from the solution thus obtained. Continue to add 0.75 to 1.25 kg of methanol (approx.
0.96-1.58) was removed in vacuo and the residue was stored at room temperature.
Leave for 10-28 days. The precipitated silibinin was filtered and washed twice with 50 ml of cold methanol. 40 in vacuum
After drying at .degree. C., the isolated crude silibinin is further purified in the following manner: 60 g of crude silibinin are dissolved in 3.degree. of technical grade ethyl acetate under heat. Subsequently, 20 g of activated carbon are added and the mixture is heated under reflux for a further 2 hours, while stirring. It was then clarified by filtration and the solution was evaporated under reduced pressure at 50°C to approximately 250 ml. This concentrate was transferred to an Ultra-Tarrax device (Ultra-
Stir for 15 minutes using a Turrax apparatus.
Mix with 25 ml of methanol during stirring. Continuing,
The mixture is left at room temperature overnight. Before suction filtration,
The silybin precipitated at this time is again stirred for 5 minutes using the Ultra-Tarrax device. The suction-filtered precipitate is washed twice with 50 ml of ethyl acetate and dried overnight in a vacuum drying box at 40°C. The product obtained is subsequently ground and dried for a further 48 hours under the same conditions. EXAMPLES The following examples serve to illustrate the invention: Example 1 Preparation of silibinin-C-2',3-dihydrogensuccinate 50 g of silibinin was dissolved in 70 ml of pyridine at 45°C, to which 50 g of succinic anhydride was added, and the mixture was
Stir at 45° C. for about 8 hours, add 30 ml of ethanol and stir the mixture further until a homogeneous mixture is formed. 60 ml of water are subsequently added to this for saponification of the phenyl acetate, with vigorous stirring, for about 30 minutes. After stirring for 1 hour at 30° C., the phenyl ester is quantitatively hydrolyzed. Completeness of hydrolysis is tested using HPLC. The hydrolysis is stopped by rapidly adding 1.7 ml of ethyl acetate to the reaction mixture thus obtained. To separate excess succinic acid and pyridine, the reaction solution diluted with ethyl acetate was added to water saturated with ethyl acetate and pH 1.85 (adjusted with dilute hydrochloric acid).
Extract twice by countercurrent. In this case, the wash water, which has been saturated and acidified with ethyl acetate, is pumped countercurrently to the diluted reaction solution, and subsequently, by addition of dilute hydrochloric acid, its pH value remains after passing through the ethyl acetate. Keep the PH value at 1.85 until . Subsequently, in order to wash out excess hydrochloric acid, the ethyl acetate phase is extracted countercurrently twice with 3.4 ml of water saturated with ethyl acetate. As soon as the pH value of the washing water becomes greater than 4.5, the organic phase is quantitatively separated and evaporated in vacuo at 40-50°C to 1/12th of the original volume.
(approximately 0.2) and then diluted with 125 ml of ethanol. The title compound is obtained by reprecipitation from ethanol/water and drying in vacuo at 50° C. for 15 hours. To prepare the analytical sample, the title compound is reprecipitated three times from ethanol/water and subsequently dried in vacuo at 50° C. for 15 hours. In the FD mass spectrum, a molecular peak appears at the expected molecular weight of 682. The IR spectrum shows 2 in the region of CO valence vibration.
It shows overlapping absorption bands, one of which is associated with the carbonyl function of the pyrone ring at a wavelength of 1635 cm ^-3 , as in the case of silibinin. The second absorption band is 1730
cm ^-3 and is due to two ester carbonyl functions. The ¹ H-NMR spectrum confirms that two esterifications have occurred. Therefore, the ratio of aromatic protons to methylene protons of succinic acid residues (determined by integration) is 8:8 (ppm range 5.9-7.1)
become. The ratio of this methylene proton (2.6ppm) to the methyl proton of the methoxy group (3.8ppm) is
8.3 and is therefore consistent with this. The chemical displacement in the case of ^{the 13} C study shows that esterification of the two alcoholic hydroxyl groups has taken place, i.e. this chemical displacement occurs at C ₁₁ and at the adjacent carbon atoms C ₁₂ -C ₁₄ Similarly, C ₂ ~
The strongest change occurs at _C4 . Elemental analysis C ₃₃ H ₃₀ O ₁₆ (molecular weight 682.60) Calculated value: C58.07% H4.4% O37.50% Actual value: 58.05% 4.57% 37.31% Example 2 Silibinin-C-2',3-dihydrogensucci Preparation of the disodium salt of nate (based on). The suspension was stirred for a further 1 hour at room temperature, the beige precipitated solid was filtered with suction and suspended twice in 150 ml of ethanol for 5-10 minutes each using a tarax.
Filter again with suction. To remove residual ethyl acetate, the product was subsequently suspended in 280 ml of ethanol at room temperature for 14 hours, filtered again with suction and then washed with 70 ml of ethanol in a vacuum drying box at 40-45 °C.
Let dry for 15 hours. This pre-dried product is subsequently ground, passed through a sieve to a particle size of less than 0.2 mm and dried again in vacuo at 40-45° C. for 48 hours. 52 g (69% of theory) of the title compound are thus obtained. This title compound has no distinct melting point. Approximately 80
It begins to sinter at 100°C and melts with bubble formation at about 100°C. UV spectrum in methanol: λ _nax = 288 nm, ε = 1.73 x ¹⁰⁴ The molecular weight of the title compound is 726.56. The compound is a slightly beige-colored, odorless, microcrystalline powder with a salt-like taste. It is easily soluble in water,
It is slightly soluble in ethanol and practically insoluble in acetone, diethyl ether and chloroform. Example of use Preparation of lyophilizate for intravenous application Disodium salt of silibinin-C-2',3-dihydrogensuccinate 75.0 mg Mannitol 10.0 mg Water for injection Total length 1.5 ml 1.5 ml of solution in a pointed ampoule with a volume of 5 ml and lyophilized using a known method. For storage purposes,
The ampoule containing the final lyophilizate is closed in the usual manner. For use, the lyophilizate is dissolved in 5 ml of sterile saline to give a clear solution.

[Brief explanation of drawings]

Figure 1 is a graph showing fatty acid distribution in microsomal liver lipids in rats and changes induced by thermal skin damage, Figure 2a is a graph showing the cell division stimulation index of blood lymphocytes, and Figure 2b is a graph showing the mitogenic index of blood lymphocytes. It is a graph showing the cell division stimulation index of splenic lymphocytes.

Claims (1)

[Claims] 1. General formula: [In the formula, m represents 1, Alk ₁ represents an alkylene group having up to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and M ₁ represents a hydrogen atom or an alkali metal atom] Silibinin derivative. 2. The compound according to claim 1, wherein m in the formula represents 1, Alk ₁ represents an alkylene group having 2 carbon atoms, and M ₁ represents an alkali metal atom. 3. The compound according to claim 1, which is the disodium salt of silibinin-C-2',3-dihydrogensuccinate. 4 General formula: [In the formula, m represents 1, Alk ₁ represents an alkylene group having up to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and M ₁ represents a hydrogen atom or an alkali metal atom] To produce silibinin derivatives, the formula: 1 part by weight of silibinin is dissolved in 1 to 2 parts by weight of pyridine, and while stirring, the general formula: React with 1 to 3 parts by weight of dicarboxylic acid anhydride [in the formula, Alk represents the same as Alk ₁ ], then add ethanol to this until a homogeneous mixture is formed,
Water was subsequently added to this under vigorous stirring, in order to hydrolyze the esters of the aromaticly bound hydroxyl groups present, and as soon as this hydrolysis was complete, the mixture was diluted with ethyl acetate and saturated with ethyl acetate. Silibinin derivatives, characterized in that they are washed with acidic water, the ethyl acetate layer is evaporated, the residue is taken up in ethanol and converted into the salt of the free carboxylic acid residue using an alkali metal hydroxide alcoholic solution. manufacturing method. 5. The method of claim 4, wherein the reaction with dicarboxylic anhydride is carried out at a temperature of about 40-50<0>C. 6 Ethyl acetate saturated and acidified water to approx.
Claim 4: Maintaining the PH value between 1.5 and 2.4
or the method described in paragraph 5. 7 [In the formula, m represents 1, Alk ₁ represents an alkylene group having up to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and M ₁ represents a hydrogen atom or an alkali metal atom] A burn treatment agent characterized by containing at least one silibinin derivative mixed with a solid or liquid drug diluent or carrier. 8 [In the formula, m represents 1, Alk ₁ represents an alkylene group having up to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and M ₁ represents a hydrogen atom or an alkali metal atom] A therapeutic agent for mushroom poisoning, characterized in that it contains at least one silibinin derivative mixed with a solid or liquid drug diluent or carrier. 9 [In the formula, m represents 1, Alk ₁ represents an alkylene group having up to 4 carbon atoms, an alkenylene group having 2 to 4 carbon atoms, and M ₁ represents a hydrogen atom or an alkali metal atom] 1. A therapeutic agent for toxic metabolic liver damage, comprising at least one silibinin derivative mixed with a solid or liquid drug diluent or carrier.