Two new benzofurans, 5, 6-dihydroxybenzofuran-2, 3-dicarboxylic acid dimethyl ester (kynapcin-13) and 5, 6, 5', 6'-tetrahydroxy[3, 3']bibenzofuranyl-2, 2'-dicarboxylic acid 2'-methyl ester (kynapcin-28) were isolated from Polyozellus multiplex, and shown to non-competitively inhibit prolyl endopeptidase (PEP), with the IC50 values of 76.80 and 0.98μM, respectively. Kynapcin-13 and -28 were less inhibitory to other serine proteases such as chymotrypsin, trypsin, and elastase.
A new neuritogenic compound NGA0187 was isolated from the fermentation broth of Acremonium sp. TF-0356. The structure of NGA0187 was determined by means of spectroscopic analysis and X-Ray diffraction. NGA0187 induced significant neurite outgrowth in PC12 cells. However, survival effect of NGA0187 on the primary culture of cerebral cortical neurons was not observed.
Cetoniacytone A (1) and some related minor components (2, 6, 7) were produced by Actinomyces sp. (strain Lu 9419), which was isolated from the intestines of a rose chafer (Cetonia aureata). The structures of the novel metabolites were established by detailed spectroscopic analysis. The absolute configuration of 1 was determined by X-ray analysis and derivatisation with chiral acids. 1 exhibits a significant cytotoxicity against selected tumor cell lines. The biosynthesis of 1 was studied by feeding 13C labelled precursors. The results suggest that the characteristic p-C7N skeleton of the aminocarba sugar is formed via the pentose phosphate pathway by cyclisation of a heptulose phosphate intermediate.
N-Phenylethylamides 1a-1f, were isolated from cultures of three limnic strains GW90a, GW102a and GW73a. Strain GW102a delivered additionally the compound cyclo (isoleucyldehydroalanyl) (2). The structure of these compounds were assigned by a detailed spectral analysis. Due to their potential use as herbicides, various related compounds 1a, 3, 4a and 4b were synthesized. The minimum inhibitory concentration (MIC) against Chlorella vulgaris, Chlorella sorokiniana, Chlorella salina and Scenedesmus subspicatus ranged from 100 to 12.5μg/ml. All these amides were found to be inactive against Mucor miehei, Candida albicans, and some bacteria.
Rapamycin is used in medicine as an immunosuppressive agent (Sirolimus; RapamuneTM) although discovered as an antifungal agent. It is thought not to have antibacterial activity. Surprisingly, we found that rapamycin inhibits the germination of Bacillus brevis Nagano spores, but is inactive against Bacillus brevis Nagano vegetative cells. Surprisingly rapamycin did not show antimicrobial activity against other Bacillus strains, including other gramicidin S-producing Bacillus brevis strains such as ATCC 9999 and BI-7, whether tested as spores or vegetative cells.