Diverse secondary metabolites produced by marine-derived fungus Nigrospora sp. MA75 on various culture media.
Bioassay-guided isolation of a fungal strain Nigrospora sp. MA75, an endophytic fungus obtained from the marine semi-mangrove plant Pongamia pinnata, which was fermented on three different culture media, resulted in the isolation and identification of seven known compounds, 2, 3, and 5-9, from a medium containing 3.5% NaCl, while a new compound, 2,3-didehydro-19α-hydroxy-14-epicochlioquinone B (10) was obtained from the medium containing 3.5% NaI. In addition, two new griseofulvin derivatives, 6-O-desmethyldechlorogriseofulvin (1) and 6'-hydroxygriseofulvin (4), were isolated and identified from the rice solid medium. Dechlorogriseofulvin (2) and griseofulvin (3) were the major components in fermentation extracts of all these culture media, while compounds 1 and 4, 5 and 6, and 10 were only present in the extract of respective culture medium. The structures of these compounds were elucidated by detailed spectroscopic analysis, and the absolute configuration of 1 was determined by CD measurement. Compounds 9 and 10 exhibited antibacterial activities toward five tested bacterial strains, while compounds 5, 6, and 8 selectively inhibited MRSA, E. coli, and S. epidermidis, and compound 3 showed moderate activity against V. mali and S. solani. Moreover, compound 10 potently inhibited the growth of MCF-7, SW1990, and SMMC7721 tumor cell lines with IC(50) values of 4, 5, and 7 μg/ml, respectively.
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China.
Zhuo
Z
Shang
Xiao-Ming
XM
Li
Chun-Shun
CS
Li
Bin-Gui
BG
Wang
D000818:Animals; D000900:Anti-Bacterial Agents; D001203:Ascomycota / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003198:Computer Simulation; D003470:Culture Media; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D008386:Marine Biology; D015394:Molecular Structure
D000900:Anti-Bacterial Agents; D003470:Culture Media