ANTAGONISTIC ACTIVITY OF ACTINOMYCETES ISOLATED FROM SALINE SOILS NEAR WITH KUMISI LAKE (GEORGIA)

Aim. To study the antagonistic activity of actinomycetes isolated from soils adjacent to Kumisi Lake (Georgia). Methods. It was used 12 samples of actinomycetes isolated from the soils adjacent to Kumisi Lake. The antibiotic activity of actinomycetes was determined using test strains: Escherichia coli К-12 (B-3254), Bacillus subtilis 26 D, Xanthomonas campestris В-1459, Rhizobium radiobacter C58, Pectobacterium carotovorum EC1by the method of agar blocks. Results. It was revealed that actinomycete samples isolated from soils adjacent to Lake Kumisi shown the most significant inhibitory effect on test strains: Escherichia coli B-3254, Rhizobium radiobacter C58 and Xanthomonas campestris В-1459. The most resistant test-strains, to the studied actinomycetes, were Bacillus subtilis 26 D and Pectobacterium carotovorum EC1. Conclusion. Isolated strain 301 of actinomycetes shown a significant antagonistic effect on all test strains and could be potential for further studies spectrum and properties of antibiotic compounds.

Synthesis and antimicrobial activity of new phosphorus-containing pyridine derivatives

The directed synthesis of new pharmacophoric molecules is one of the urgent tasks of organic chemistry. A special place in this area is occupied by vital nitrogen-containing heterocycles and their derivatives, on the basis of which new promising precursors of drugs are created. For example, pyridinium salts are part of such well-known drugs as pyridoxine, mexidol and metadoxine. Phosphorus-containing pyridine derivatives, among which compounds with cytotoxic and antimicrobial properties have been identified, are also being actively studied now. Thus, the development of convenient approaches for obtaining new functional phosphorus-containing pyridine derivatives is an important and timely task. Special attention is paid to synthetic methods that correspond to the PASE (pot, atom and step economy) paradigm. Using this approach, we have synthesized hydrochlorides and tosylates of 4-bis(2-phenylethyl)chalcogenophosphoryl-pyridine, not described previously, by practically quantitative interaction of the available 4-bis(2-phenylethyl)chalcogenophosphorylpyridines with hydrochloric or 4-methylbenzenesulfonic acids at room temperature or slight heating (40-45 °C). The reaction proceeds regioselectively on the nitrogen atom of the base pyridine. The second reaction center in the 4-bis(2-phenylethyl)chalcogenophosphorylpyridine molecule, chalcogenophosphoryl group, does not participate in the studied process, even when using an excess of hydrochloric acid. The starting 4-bis(2-phenylethyl)chalcogenophosphorylpyridines are easily obtained on the basis of the original reaction of pyridine with secondary phosphine chalcogenides with the assistance of electron-deficient acetylenes. Using the example of microorganisms of different taxonomic groups: Bacillus subtilis B-406, Enterococcus durans B-603, Penicillium citreo-viride F-1777, Escherichia coli B-1238, we have found that the target hydrochlorides and tosylates of 4-bis(2-phenylethyl)chalcogenophosphorylpyridine exhibit pronounced antimicrobial activity against non-spore gram-positive microorganisms.

Two antimicrobial compounds drimane sesquiterpene polygodial and 11-hydroxydrim-8-en-7-one from the stem bark of Drimys arfakensis Gibbs. (Winteraceae)

Antimicrobial-guided fractionation and isolation of the bioactive compounds from the stem bark of Drimys arfakensis Gibbs. were carried out. Two antimicrobial compounds were isolated. The sructures of the compounds were elucidated by spectroscopic methods such as 1H NMR, 13C NMR, 2-D NMR, ESI-MS and EI-MS. Based on the spectroscopic data, the two antimicrobial compounds were polygodial, 1 and and 11-Hydroxydrim-8-en-7-one, 2. . Compound 1 exhibited very strong activity against methicillin-resistant Staphylococcus aureus (MRSA) (B-1823), and yeast-like fungi Candida albicans (B-2219) with both having MIC values of 7.8 µg.mL-1. It also showed strong activity against gram negative bacteria Escherichia coli (B-1634 ) with MIC value of 31.2 µg.mL-1 . While compound 2 only possesses strong activity against S. aureus (MRSA), no activity against C. albicans and E. coli was observed. This is the first report on the antimicrobial activity of compound 2 and on the isolation of these two compounds from D. arfakensis Gibbs.