Chemical Investigation Of Two Strains Of Endolichenic

Endophytic fungi refer to those microorganisms that spend all or almost the whole life cycle in the host and the host will not show any pathogenic characteristics.Endophytes and symbionts can evolve into a unique symbiotic relationship in the long-term coevolution process.The interaction of species and stress relationship from environment can produce active secondary metabolites with novel structure,such as important anticancer substances paclitaxel and camptothecin,penicillin with good antibacterial activity,lovastatin,cyclosporin and caspofungin,which can be used to treat leukemia.These results showed that there were immunosuppressive activity but no cytotoxic activity in these fungi.Lichen is a kind of fungi that can be used as symbiotic bacteria.Some nonlichen fungi that do not cause symptoms of their own can often be found.They form organic compounds with photosynthetic symbiotic algae,namely lichen endophytic fungi.It usually grows on the surface of rocks and tree trunks,and can survive in extreme special environments.Fungi living in these special environments are important sources of natural products with novel structure and small molecules.At present,the structural types isolated from endophytic are alkaloids,anthraquinones,polyketones,terpenes,steroids,peptides and simple aromatic compounds.In this study,two endolichenic fungi collected in Yunnan Province,People's Republic of China,were selected for chemical studies.The crude extracts prepared from solid-substrate fermentation cultures were fractionated by column chromatography and reversed-phase high performance liquid chromatography(RP HPLC)using various stationary and mobile phases.The structures of the new comopunds were elucidated by nuclear magnetic resonance(NMR),mass spectrometry(MS),in combination with circular dichroism(CD)and chemical derivatizations.Thirteen compounds were identified from the endolichenic fungus Preussia Africana,including two new polyketones preussochromones F(1)and G(2)and 12 known compounds preussochromone C(3),2-(4-hydroxyphenyl)acetate(4),7-hydroxy-2,5-dimethylchromone(5),makomotindoline B(6),2,3'-dihydroxy4-methoxy-5',6-dimethyldiphenyl ether(7),quercilolin(8),2,2',3,4'-tetrahydroxy-5,6'-dimethyldiphenyl ether(9),3-hydroxy-5-methylphenyl ether(10),pulchellalactam(11),4-hydroxy-6-methoxy-5-methyl-1(3H)-isobenzofuranone(12)andakolitserin(13)Seven compounds were identified from endolichenic fungi sarcosomataceae sp.,including three new pimarane diterpenoids sarcosenones A–C(14–16)as well as four known compounds 9?-hydroxy-1,8(14),15-isopimaratrien-3,7,11-trione(17),lamellic anhydride(18),2,8-dihydroxy-3,4-dihydronaphtalen-1(2H)-one(19)and 5-carboxymellein(20).The cytotoxic activities of five new compounds sarcosenones A–C(14–16),preussochromones F(1)and preussochromone G(2)were evaluated by MTT method.Sarcosenone A(14)showed moderate cytotoxicity against a variety of tumor cell lines.