Study On Secondary Metabolites Of Two Fungi From The South China Sea And Their Biological Activities

Exactly different from the terrestrial environment,the extremely living circumstances of the deep oceans,on which is high salt,high perssure,low temperature.Marine microorganisms form an absolutely different metabolic patterns,which lead to produce massive natural products with unique structure and significant biological activity.As one of the most important components in marine microorganisms,marine fungi have attracted the interests of chemists and biologists to search for lead compounds with potentially medicinal values.Therefore,a comprehensive and systematical research on the chemical constituents and their biological activities of Hypoxylon rubiginosum FS521 and Penicillium chermesinum FS625 was carried out.The extracts of the marine fungi were isolated and purified by silica gel column chromatography,RP-18 chromatography,sephadex LH-20 column chromatography and HPLC methodology,in combination with modern spectroscopic techniques such as 1H NMR,13C NMR,COSY,HMBC,HSQC,NOESY,MS,IR,UV,OR,CD and X-ray to identify the relative and absolute configurations of their secondary metabolites.As a result,39 compounds were identified,8 new compounds(including 2 new natural products)and one crystal structure.Compounds A1-A4 and B1-B10 were tested for their cytotoxic activities against SF-268,MCF-7,HepG-2 and A549 tumor cell lines with SRB method,the results suggested that compound A3 showed significant cytotoxity against SF-268,MCF-7,HepG-2,and A549 cell lines with IC50 value of 1.9,3.2,2.5,and 5.0 μM,respectively.Compounds Al,A2,A4 show moderate cytotoxity against the four cell lines with the IC50 value ranging from 18.89 to 69.62 μ;Compounds A1-A4 and B1-B10 were tested for inhibitory activities of NO production in the LPS-induced RAW 246.7 mouse macrophages by Griess method.The results exhibited that compounds A1 and A4 showed inhibitory activities of NO production in the LPS-induced RAW 246.7 with IC50 value of 21.44 ± 0.88 μM and 59.75± 3.52 μM,respectively,comparing to positive control indomethacin(IC50:47.14 ± 2.76 μM).However,compounds B2-B3,B4 and B6 showed weak inhibitory activities of NO production with IC50 value in the range of 69.65-95.84 μM,aminoguanidine as positive control(IC50:24.80 μM).Antibacterial activities and α-glucosidase inhibitory effect of compounds A1-A4 and B1-B10 showed no effects.The study on the metabolites and biological activities of the two strains not only enrich the structural diversity,but also provide important leading compounds for new drugs development.