| The ocean is a treasure-house of natural biological resources. The unique environment of ocean has led to the diversity of marine microbial species and their secondary metabolites. As an important component of marine microbes, marine fungi have become a major source of new natural products of marine microbes as a result of the unpredictable genetic background and high yield of secondary metabolites, which has played more and more important role in the discovery of nature drug molecules,environmental contaminant treatment and marine environment restoration, etc. Therefore,the research and development of marine drugs are of great significance for the full use of marine biological resources, the benefit of human health and social development.In order to seek out the secondary metabolites with novel structure and remarkable activity, we carry out the research to have the marine samples isolated and screened though the method of chemical screening (TLC and HPLC Fingerprints). Two strains of potential fungi were obtained for the further large-scale fermentation. The fermentation followed by extraction was performed. At last, the structural analysis and bioactivities of pure compounds were studied systematicly.1. The extraction, purification and structural identification of secondary metabolite.Eighteen compounds (1-18) were isolated and purified by various chromatographic techniques, including Silica gel, Sephadex LH-20 column and HPLC chromatography from Aspergillus sp. SCS-KFD03, identified as phomaligol A1 (1), 5-(acetoxymethyl)furan-3 acid (2), phomapyrone C (3), 4-hydroxyisobenzofuran-1(3H)-one (4), penicil-livinacine (5), 22(E)-5a,8a-epidioxyergosta-6,22-dien-3p-ol (6), lucidal (7), dank-asterone A (8), bis-(2-methylheptyl)-phthalate (9), 3β,5a-dihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (10), (22E,24R)-ergosta-5,7,22-trien-3β-ol (11), leporin B (12),astellolide G (13), astellolide B(14), astellolide A (15), 3β,4a-dihydroxy-26-methoxyer gosta-7,24(28)-dien-6-one (16), 4-methoxy-3,5-dimethyl-6-(2-methylbutanoyl)-2H-pyran-2-one (17) and 2’8’-dimethyl-5-phenyl-4a’,5’,6,7’,8’,8a’-hexahydro-2’H,3H-spiro[furan-2,1 ’-naphthalen]-3-one (18). Six compounds (19-24) were isolated and purified from Penicillium sp. SCS-KFD03, identified as 2-(4-hydroxy-2- methoxybenzyl)-5-methoxyphenol (19), ES-242-3 (20), 6-Ethy 1-2,4-dihydroxy-3-methyl benzaldehyde(21), 2-(4-hydroxyphenethyl) acetate (22), 4-(2-Hydroxyethyl)phenol (23) and penicillide(24). Compounds 17-19 are new ones among all the compounds.2. Biological evaluation. The pure compounds were evaluated for antioxidant activity, acetylcholinesterase and a-glucosidase inhibitory activities via in vitro biological activity screening model. The experimental results showed that compounds 11, 13, 14, 16,20, 21, 22, 23 and 24 have a certain antioxidant activity towards DPPH free radical,while the free radical scavenging rate ranged from 10.26 % to 39.81 %. Compounds 5, 6,7, 9,16 and 21 showed weak inhibitory activities against acetylcholinesterase, while the Inhibition rate ranged from 10.17 % to 43.89 %. Compounds 5, 8, 9,12, 21, 22 and 24 have a-glucosidase inhibitory activities, compound 5,12 and 21 has stronger inhibitory activity against a-glucosidase than the positive drug acarbose,while compounds 8 and 9 exhibited inhibitory activity against a-glucosidase as strong as the positive drug. |
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