Studies Of Secondary Metabolites From An Endophytic Fungi DS37 Of Decaisnea Insignis

The research object of this subject is the strain DS37,which was isolated from the stem of Decaisnea insignis with higher antimicrobial activities.Finally,DS37 was identified as Aspergillus tubingensis by morphological and molecular biology characteristics.The DS37 was fermented with rice medium,and the dried fermented product was soaked used petroleum ether,ethyl acetate and methyl alcohol.The extraction fluid was concentrated under reduced pressure to obtain crude extract.The crude extract was separated and purified by silica gel and gel column chromatography combined with thin layer chromatography and recrystallization to obtain 16 compounds.According to the physical and chemical properties of the pure compounds and various spectral data and X-single crystal diffraction.Sixteen compounds were identified as: ergosta-7,22-dien-3β-yl-palmitate(1),24 alkyl acid(2),1,3-Dicapryloyl-2-linoleoylglycero(3),alternariol methyl ether(4),alternariol(5),asperpyrone C(6),asperpyrone D(7),2,4,6a,10,12-Pentahydroxy-6,6a-dihy-drodinaphtho[2,1-b:1’,2’-d]furan-5,9-dione(8),leptosphaepi(9),daucosterol(10),5,5’-dimethy-7-hydroxy-4,4’,7’-trimethoxy-6,8’-bicoumarin(11),3-(5-oxo-2,5-di-hydrofuran-3-yl)propanoic acid(12),5,5’-dimethy-4,4’,7,7’-tetramethoxy-8,8’-bicoumarin(13),7-hydroxy-4-methoxy-5-methylcoumrin(14),stigmasta-7,22-diene-3β,5α,6α-triol(15),quercetin3-O-β-Lrhamnopyranoside(16).3-(5-oxo-2,5-di-hydrofuran-3-yl)propanoic acid(12)was a new compound,compounds 1-3,6,8-16 were isolated from the culture of the Aspergillus tubingensis for the first time.Four bacteria(Escherichia coli,Streptococcus lactis,Staphylococcus aureus,Pseudomonas aeruginosa)and five plant pathogenic fungi(Fusarium graminearum,Alternaria alternata,Sclerotinia sclerotiorum,Botrytis cinerea,Phytophthora capsici)were used to test the antimicrobial activity of the 16 compounds.The results showed: compounds 4,5,7 and 14 displayed equivalent inhibitory effects with the positive drug for the four strains of bacteria,compounds 4,5,9,11-14 behaved similar or even better inhibitory effects thanpositive control for five phytopathogenic fungi.The antioxidation activity of compounds 3-8 and 11-13 were tested by scavenging the DPPH(2,2′-dipheny-1-picrylhydrazyl)radical.The results showed: none of the compounds revealed significant antioxidant effects.Four human common tumor cell lines(PC-3,A-549,MCF-7,HepG2)and one normal cell line(L02)were used to test the antitumor activity of 4-9,11-13.The results showed: compounds 4,5,7,11 and 13 exhibited varying degrees of anti-tumor effects.In particular,compounds 4,11 against tumor cells HepG2 and7,13 against tumor cells A-549 revealed prominent antitumor effects.