Studies On Secondary Metabolites Of Two Microorganism Strains Associated From Different Sources

In order to explore new chemical constituents available for new drug research, the chemical constituents of Streptomyces hygroscopicus, and endophytic fungus Penicillium sp. DVCF5091associated with Dysosma versipellis.were systematically studied in this project.The strains were cultured for scale-up in biofermenter or by resting cultivation method. The achieved crude extracts were separated by silica gel, Sephadex LH-20, prep-HPLC, PTLC chromatography. The isolated compounds were identified by1H-NMR,13C-NMR,2D-NMR,HRESIMS, IR, UV spectral technologies.Twenty-six compounds were isolated and identified from Streptomyces hygroscopi-cus, and endophytic fungus Penicillium sp. DVCF5091. Among these compounds, five new compounds were elucidated in detail. Putative analysis of their relating biosynthesis pathways showed that a complex process was involved in how secondary metabolites were biosynthesized by microorganisms. Diversely relating precursors can be chosen as the starters untilized by corresponding enzymes, to form different characteristic second-ary metabolites. Meanwhile, at different growing phases of microbials, the regulating enzymes reacted on precursors through appropriate and specific paths to biosynthesize different derivates. A good elucidation on biosynthesis of secondary metabolites is avail-able for us to understand their diversity properly.1. The HPLC-DAD-MS analysis of Streptomyces hygroscopicus revealed the main me-tabolite constituent as Geldanamycin. In addition,14compounds were insolated and identified from its crude extract. which followed as Geldanamycin (1),17-O-demethyl geldanamycin (2), Reblastatin (3), Autolytimycin (4), Discongeldanamycin(5), Geldanamycin lactone(6), Thiazinogeldanamycin (7),4,5-dihydrothiazinogeldanamycin (8), Hygrocin A6(9),1,22-dehydratehygrocin A6(10), L-155,175(11), Hygrolidin(12),17-Hydroxycyclooctatin (13),(R)-6-(2,3-dihydroxy-3-methylbutyl)indolin-2-one (14). Among them, compounds (5),(6),(10) are new compounds. Compounds (5) and (6) are characterized as new geldanamycin derivates with thiazine cycle. Compounds (10) is the analogue of Hygrocin A6(9).Through fluorescence polarization experiment, geldanamy-cin as the positive drug (IC50=0.31μM), the Hsp90inhibition activity of geldanamycin derivates (1-8) were tested. The results showed that the activity of17-O-demethyl geldanamycin (2), Reblastatin (3) and Autolytimycin (4) are almost equal to geldanamy-cin with same fold of activity. Especially, the sulphur atom introducted in C-19, ester or open-ring type substituted in C-20of geldanamycin skeleton can effective decrease their activity on Hsp90.2. The endophytic fungus DVCF5091was isolated from the leaves of Dysosma versipel-lis.12compounds were isolated and identified from its crude extract, and followed as11β-acetoxyisoaustinone (15), Isoberkedienolactone (16), Austin (17),Austinolide (18), Dehydroaustinol (19), Dehydroaustin (20), Chrodrimanin A (21), Chrodrimanin B (22), O-methylmellein (23),3-(propan-2-ylidene)-pyrrolidine-2,5-dione (24),(E)-3-[2,5-Dioxo-3-(propan-2-ylidene)-pyrrolidin-1-yl]acrylic acid (25), N-(4-hydroxy-2-methoxyphenyl)-acetamide (26). Compounds (15),(16) are new com-pounds. Compound (15) is anAustin-like meroterpenoid compound, and compound (16) is a butyrrolactone compound. Through application of experimental and theoretical ECD analysis, the absolute configuration assignment of16is confirmed. These compounds showed weak cytotoxicities in vitro against HCT-116, HepG2, BGC-823,NCI-H1650, and A2780cell lines with IC5o>10μM.