Study On Secondary Metabolites From Two Marine-derived Fungi

The complex and special ocean environment urged marine-derived fungi produce structurally novel and biologically active secondary metabolites. A study on two strains of marine fungi Hansfordia sinuosae and Penicillium commune from South China Sea was carried out, which included screening for strains; isolation, purification and structural elucidation of secondary metabolites, and evaluation of antimicrobial activities for pure compounds.25 marine fungal strains were collected from the marine sediment sample(South China Sea). Two strains were screened out of 25 marine fungal strains by chemical screening methods(TLC, HPLC). Secondary metabolites were isolated and purified from their fermentation broths using silica gel column chromatography, semi-preparative HPLC, sephadex LH-20 chromatography and other chromatographic methods. Structures were elucidated by extensive spectroscopic analysis including 1D and 2D-NMR, OR, MS, IR, UV.Eleven compounds were isolated from fermentation broth of Hansfordia sinuosae. Their structures were identified as five isocoumarins,(E)-6,8-dihydroxy-3-(prop-1-en-1-yl)-1H-isochromen-1-one(HJ-1),(R)-6-hydroxymellein(HJ-2), 3-methyl-6,8-dihydroxyisocoumarin(HJ-3), orthosporin(HJ-4), diaporthin(HJ-5); two quinones, chrysophanol(HJ-6), 1,5-dihydroxy-3-methoxy-7-methylanthracene-9,10-dione(HJ-7), two steroids,(22E, 24R)-ergosta-7,22-dien-3?,5?,6?,9?-tetraol(HJ-8), 3,5,9-trihydroxyergosta-7, 22-dien-6-one(HJ-9); other types: cyclonerodiol(HJ-10), succinic acid(HJ-11). Compound HJ-1, a novel isocoumarin, showed moderate activity towards Vibrio anguillarum, Vibrio arahaemolyticus and Bacillus subtilis with MIC 25 ?M. Compound HJ-3 was isolated from Hansfordia sinuosae for the first time.Eleven pure compounds were isolated from the fermentation broth of Penicillium commune. Their structures were elucidated as: 2-acetyl-4(3H)quinazolinone(WHJ-1), O-acetylbenzene-amidinocarboxylic acid(WHJ-2), 2-pyruvoylaminobenzamide(WHJ-3), thymine(WHJ-4); N-acetyldopamine(WHJ-5), ergosta-5,7,22-triene-3?-ol(WHJ-6),(22E,24R)-5?,8?-epidioxyergosta-6,22-dien-3?-ol(WHJ-7), syringate(WHJ-8), p-hydroxybenzoicacid(WHJ-9), 3,4-dihydroxybenzoicacid(WHJ-10), bis(2-ethylhexyl) adipate(WHJ-11). Compounds WHJ-2 and WHJ-3 were isolated from Penicillium commune for the first time.Research on secondary metabolites of marine-derived fungi had a huge boost for the discovery of new drugs, environmental protection, and biological materials. This study provided a foundation for deepening the study of natural products, and enriched the diversity of natural products structures from marine-derived fungi.