PHYSIOLOGICALLY ACTIVE SUBSTANCES, A PROCESS FOR THE PREPARATION THEREOF AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM

Abstract: Physiologically active substances are extracted from infected tissues inoculated with a poxvirus. They have inhibitory action against the formation of kallikrein and are useful as drugs such as anti­ inflammatory, analgesic and antiallergic agents.

Description: The present invention relates to a physiologically active substance extractable from infected tissue, a process for its production, a pharmaceutical composition containing it and its use for the preparation of analgesic or antiallergic compositions. Investigation of material extracted from infected tissues, organs or cultured cells obtained from an animal innoculated with a poxvirus has led to the finding of a physiologically active substance having an inhibitory action against the formation of kallikrein, together with a process for its preparation. In Ganea et al., J. Immunol. 138, 1208-1214 (1987) there is described a proteinase inhibitor having activity against trypsin and, to a partial extent, kallikrein, obtained from human T cells infected with HTLV1 virus and normal rabbit spleenic T cells. The process did not apparently involve deproteinization. An active fraction of 1-10 kDa was obtained from supernatant by incubation and dialysis. According to the present invention there is provided a process for the production of a physiologically active substance having an inhibitory action against the formation of kallikrein, characterised in that i. tissue, organs or cultured cells obtained from an animal infected with a poxvirus is homogenised with an aqueous extraction medium, ii. the resulting extract is subjected to deproteinization, iii. the deproteinized extract is adsorbed on an adsorbent, iv. the adsorbed material is eluted with a basic aqueous elution medium, v. the eluted material is fractionated to obtain a molecular weight fraction of 1,000 - 20,000. The preferred process is described hereafter. The term "infected tissue" as used in this specification is defined as meaning animal tissue, organs or cultured cells obtained from an animal inoculated or otherwise infected with a poxvirus. Examples of poxvirus which can be used include vaccinia virus, cowpox virus, variola virus, infectious ectromelia virus, or monkeypox virus, parapox virus such as orf virus, paravaccinia virus or bovine papular stomatitis virus, capricopoxvirus such as sheeppox virus, goatpox virus or lumpyskin disease virus, avipox virus such as fowlpox virus or hare fibroma virus, leporipoxvirus such as rabbit myxoma virus or rabbit fibroma virus, swinepox virus and Yaba monkey virus or Tarapox virus. Many animals or birds can be infected; e.g. a rabbit, sheep, goat, pig, cow, horse, monkey, hamster, guinea pig, rat, mouse or hen can be employed. The animal or bird can be selected according to a species of poxvirus and other conditions. Also any kind of cultured cells in which the selected poxvirus can multiply, may be used, for example, cultured cells or tumor cells of kidney, skin, lung, testis, liver, muscle, adrenal, thyroid gland, brain, nerve cells or blood cells of rabbit, sheep, goat, pig, cow, horse, monkey, hamster, guinea pig, rat, mouse, hen or their embryo, cultured cells derived from human such as Hela cells or decidua of the hatching egg can be employed. The infected tissues are collected under aseptic conditions and ground to as small a size as possible. An extraction medium is added to the ground material which is then homogenized. As an extraction medium, distilled water, physiological saline, weakly acidic or basic buffer may be used, and if desired, a stabilizer such as glycerin, a disinfectant or preservative such as phenol, or an inorganic salt such as sodium chloride, potassium chloride or magnesium chloride can be added to the medium. At that time, the extraction can be facilitated by a procedure to disintegrate cell tissues, such as freeze-thaw extraction, sonication or treatment with a detergent or an enzyme dissolving cell membrane. The resulting emulsion is filtered or centrifuged to remove tissue fragments. The filtrate or supernatant is deproteinized, which can be carried out according to a known method, for example, heating, sonication, treatment with a protein-denaturant such as an acid, a base, urea, guanidine, an organic solvent or a detergent, iso-electric point precipitation or a salting-out technique. Subsequently, the denatured proteins thereby precipitated are removed by filtration using a filter paper such as cellulose or nitrocellulose, a glass filter, sellaite, Seitz's filter, ultrafiltration, gel filtration, ion-exchange chromatography or centrifugation. The resulting extract containing the active substance is acidified preferably to pH 3.5 - 5.5, by addition of an acid such as hydrochloric acid, sulfuric acid or hydrobromic acid, and then subjected to adsorption on an adsorbent such as active carbon, kaolin or an ion-exchange resin. The adsorbent can be added to the extracted solution and it is stirred, or the extracted solution can be passed through a column of the adsorbent. To elute the material containing the active substance of the present invention, a basic solution is added to the absorbent, preferably adjusting the suspension to pH 9 - 12, and then the mixture is incubated or stirred at room temperature or at a suitable temperature above room temperature by heating. The elution is achieved by removing the absorbent according to a known method such as filtration or centrifugation. After the eluate is adjusted to near neutral by addition of an acid, fractionation based on molecular weight such as ultrafiltration or gel filtration is carried out to give the active substances of the present invention. The following examples, describe the preparation of the physiologically active substance of the present invention. Example 1 Vaccinia virus was inoculated to the skin of healthy adult rabbit. The inflamed skin was cut off under aseptic conditions and well ground. Aqueous phenol solution was added to this ground material and subjected to homogenization, and the emulsion was filtered by centrifugation. The resulting filtrate was adjusted to pH 4.8 - 5.5, and then heated in a stream of 100°C steam. After removing proteins thereby precipitated by filtration, the filtrate was adjusted to near pH 9 by addition of sodium hydroxide, heated at 100°C and filtered. The filtrate was adjusted to pH 4.5 and 7.5% active carbon was added thereto. After stirring for 4.5 h, the suspension was filtered. Water was added to the resulting active carbon and the suspension was adjusted to pH 10.9 by addition of sodium hydroxide. The extraction procedure was carried out by stirring for 1.5 h at 60°C. The suspension was filtered to remove the active carbon. The filtrate was adjusted to near pH 8 by addition of hydrochloric acid and concentrated to dryness under reduced pressure. The residue was dissolved in distilled water and any insoluble matter was removed by filtration. Subsequently, the solution was filtered through a ultrafiltration membrane eliminating substances the molecular weight of which is more than 20,000. To the remaining solution concentrated to small amount, distilled water was added and it was filtered again. The procedure was repeated several times. Next the resulting filtrate, which contains substances of molecular weight less than 20,000, was subjected to ultrafiltration again using a membrane eliminating substances molecular weight of which is more than 1,000 in the same manner as mentioned above to give the substance of the present invention, which did not pass the membrane. Example 2 The extract prepared in the same deproteinizing process as Example 1 was adjusted to pH 3.8 and 15% active carbon was added thereto. After stirring for 5 h, the suspension was filtered. To the resulting active carbon, aqueous solution of sodium hydroxide (pH 11.5) was added and the suspension was stirred for 3 h at 45°C. The active carbon was removed by filtration. The filtrate was neutralized and subjected to the ultrafiltration procedures, which was carried out in the same manner as Example 1, to give the physiologically active substance of the present invention. The substance of the invention thus obtained was concentrated to dryness under reduced pressure. As a result of weighing the dried substance, the yield of the substance of the present invention is 0.5 - 1.0 g when 1 kg of infected skin-tissues of mature rabbit are employed. The physical and chemical properties of the physiologically active substance obtained in the above examples are as follows. 1) Appearance: Pale yellowish brown and hygroscopic powder. 2) Solubility: Soluble in water, methanol and acetone. Insoluble in benzene and ether. 3) Acidity: The pH of aqueous solution thereof is pH 6.5 - 7.5. 4) Molecular weight: 1,000 - 20,000 5) Ultraviolet adsorption: λmax = 265 - 275 nm. 6) Color reaction: Positive; amino acid, sugar, phosphorus. Negative; protein, phenol. The following descriptions serve to illustrate pharmaceutical studies of the substance of the present invention. (1) Inhibitory action against the formation of kallikrein Kallikrein is a group of proteinases distributed in the plasma and tissues of various kinds of animals. Inactive prekallikrein is converted into active kallikrein through an activation of blood coagulation factor XII. The inhibitory action of the substance of the present invention against the formation of kallikrein was assayed according to the method described in Example 1 of EP-A-0259857. That is, in the primary reaction, kaolin suspension was added to the human plasma diluted with physiological saline. After a certain while, Lima Bean trypsin inhibitor was added to terminate the activation of kallikrein. In the second reaction, the amount of kallikrein formed in the primary reaction was measured by the use of a synthetic substrate specific to kallikrein, such as D-Pro-Phe-Arg-p-nitroaniline. In the above reaction system, the activity of the test substance to inhibit the formation of kallikrein was measured by mixing the test substance with the human plasma prior to addition of kaolin suspension. An example of the results is shown in Table 1. Test substance IC₅₀ (µg/ml) Substance of the invention 58 Ketoprofen 700 Kallikrein acts upon kininogen to liberate kinins such as bradykinin, hence the liberation of kinins is depressed by inhibition of the formation of kallikrein. As can be seen from Table 1, the substance of the present invention has excellent inhibitory action against the formation of kallikrein. The inhibitory action of the substance is superior to that of Ketoprofen analgesic action of which is partly due to the inhibitory action against the liberation of bradykinin. In addition, the substance of the present invention showed a remarkable effect intravenously on carrageenan or sodium urate crystal induced paw edema in rats. Although the results are not shown herein, other fraction than the substance of the present invention, which is fractionated by ultrafiltration, scarcely show any inhibitory action against the formation of kallikrein. Kinins such as bradykinin have various physiological actions, for example, enhancement of vascular permeability, contraction of smooth muscles, development of pain and hypotensive action, thus are playing an important role for function control in living bodies. As stated earlier, the inhibition of the formation of kallikrein suggests the inhibition of kinins liberation, therefore, the physiologically active substance of the present invention having remarkable inhibitory action against the formation of kallikrein is extremely useful as drugs such as antiinflammatory, analgesic and antiallergic agents.

Claims: A process for the production of a physiologically active substance having an inhibitory action against the formation of kallikrein, characterised in that i. tissue, organs or cultured cells obtained from an animal infected with a poxvirus is homogenised with an aqueous extraction medium, ii. the resulting extract is subjected to deproteinization, iii. the deproteinized extract is adsorbed on an adsorbent, iv. the adsorbed material is eluted with a basic aqueous elution medium, v. the eluted material is fractionated to obtain a molecular weight fraction of 1,000 - 20,000. A process according to claim 1 wherein the poxvirus is vaccinia virus. A process according to claim 1 or claim 2 wherein infected tissue from rabbit skins is utilised. A process according to any preceding claim wherein the deproteinized extract is adjusted to pH 3.5 - 5.5 prior to adsorption. A process according to any preceding claim wherein the elution is carried out at pH 9 - 12. A process according to any preceding claim wherein the eluted material is subjected to ultrafiltration. A process according to any preceding claim wherein the adsorbent is selected from active carbon, kaolin and an ion-exchange resin. A physiologically active substance having an inhibitory action on kallikrein obtained by the process of any preceding claim. A substance according to claim 8 characterised by the following properties: Appearance: pale yellowish brown hygroscopic powder Solubility: soluble in water, methanol and acetone insoluble in benzene and ether Acidity: the pH of an aqueous solution is 6.5-7.5 Molecular weight: 1,000 - 20,000 Ultraviolet absorption: λ max = 265 - 275 nm. Color reaction Positive: amino acid, sugar, phosphorus Negative: protein, phenol. A pharmaceutical composition comprising as an active ingredient a substance according to claim 8 or claim 9. Use of a substance according to claim 8 or claim 9 for the preparation of an anti-inflammatory, analgesic or antiallergic composition.

Inventors: SHIBAYAMA, YOJI INSTITUTE OF BIO-ACTIVE SCIENCE, TOYOMAKI, YOSHIO INSTITUTE OF BIO-ACTIVE SCIENCE
Applicants: NIPPON ZOKI PHARMACEUTICAL CO. LTD.
Application year: 1988
Main classification: A61K37
IPC codes: A61P29, A61K35, C12R1, C12P1, C07K1, A61P37, A61P25, A61K38, C07K14, C07G99