Secondary Metabolites Of Two Endophytic Fungi

Endophytic fungus refers to that who live in a plant for at least part of its life cycle,without causing apparent disease.Endophytic fungi supposed to have special biogenetic pathway due to the unique habitats and long-time co-evolution with their host have become a promising resource of numerous structurally diverse secondary metabolites with remarkable bio-activities.This dissertation reports the isolation structure elucidation and bioactivity of secondary metabolites produced by two endophytic fungi including one,Curvularia geniculate Y12,obtained from Ginkgo biloba of Square Mountain,and the other Alternaria alternate L-10,obtained from Capparis spinosa L.The crude extracts derived from the cultures of the two fungi were repeatedly fractionated by a combination of chromatographies over normal-and reverse-phase ODS silica gel,gel filtration over Sephadex LH-20 and HPLC to afford a total of 19 compounds.Including eight new compounds,which were determind by spectroscopic analyses including(HR-ESI-MS,LC-MS,IR,1H NMR,13C NMR,HMQC,1H-1HCOSY,HMBC,NOESY,ROESY)and X-ray diffractions.Curvularia sp.Y12,an endophytic fungus,was isolated from Ginkgo biloba of Square Mountain.The liquid fermentation,followed by extraction and fractionation,gave 7 compounds including 3 new Lactone compounds.All the compounds were evaluated for cytotoxic activity.acetylcholine inhibitory and antibacterial activity,However,None of compounds showed strong antifungal activity against the tested fungal and significant cytotoxic activity.The endophytic fungus Alternaria alternate L-10 dwelling in the healthy rhizome of Capparis spinosa L.was shown to be capable of producing 12 compounds with 2 novel carbon skeletons.All the new compounds were evaluated for cytotoxic activity,acetylcholine inhibitory and antibacterial activity,Three new compounds just showed extremely weakly cytotoxicity against the tested cell lines at a concentration of 30 μM.Furthermore,natural bioactive products from plant endophytic fungus were reviewed briefly.