[New biologically active substances from protozoa and an evaluation of their action]

Novel biologically active substances were obtained from nonpathogenic for humans and free-living protozoa: Crithidia oncopelti, Trypanosoma lewisi, and Astasia longa. There were studied conditions of biosynthesis, composition and biological activity of the total lipid fraction from the protozoa species, sucrose ethers and fatty acids, the latter were isolated from A. longa--(astazilide preparation), reserve beta-1,3 glucan from A. longa (astazian preparation), and fraction of surface glycophospholipids and peptides from Crithidia oncopelti (GLP preparation). Two of three preparations studied (astazilide and GLP) are the complexes of natural substances with certain composition. Conditions of the protozoa cultivation were developed to provide standardization of the complex composition. Division of the complexes into separate components decreased or abolished the biological activity. It was established that the substances studied modify biological reactions, that is exert a systemic effect. They may be used for inhibiting the growth of experimental tumors and preventing the metastatic spreading in tumor-carrier animals. The substances obtained belong to the group of nonspecific stimulators for cellular immunity which can be used in medicine, veterinary medicine, food industry, pharmacologic industry and cosmetology.