Characterization And Bioactivity Of Secondary Metabolites From Two Fungal Endophytes

One strain of endobryophytic fungus,Botrysphaeria laricina,and one strain of endophytic fungi,Leptosphaeria sp.L1201,were chemically investigated in this paper.A total of 41 compounds including 11 new ones were isolated by repeat column chromatography of silica gel,sephadex LH-20,and C18 reverse-phased silica gel as well as semi-preparative HPLC.The structures of these compounds were determined by methods of NMR,MS,IR,UV,and single-crystal X-ray diffraction analysis.Some compounds were screened for their cytotoxic activity,inhibition of NO production activity,and quinone reductase inducing activity.Some compounds exhibited significant bioactivity.One strain of endobryophytic fungi,Botrysphaeria laricina,isolated from healthy tissues of the moss Rhodobryum umgiganteum was cultivated in Czapek medium and the metaboities were chemically studied.Seven new compounds,botrysphaerins A-E(1-5)and tricycloalternarenes K and L(6 and 7),together with 14 known compounds sphaeropsidins A and B(8 and 9),aspergiloid B(10),fusaproliferin(11),(-)-terpestacin(12),tricycloalternarenes 3a,4b,and lb(13-15),stigmasterol(16),β-sitosterol(17),(22E)-ergosta-6,9,22-trien-3β,5α,8a-triol(18),(22E)-ergosta-4,6,8(14),22-tetraen-3-one(19),hexadecanoic acid(20),and 1-O-pentadecanoyl-sn-glycerol(21)were obtained.Some compounds were screened for their cytotoxic activity,inhibition of NO production activity,and quinone reductase inducing activity.Compound 3 showed moderate cytotoxic activity against the MDA-MB-231,A549,Hep G2,and Hela cancer cell lines.Compounds 1,3-7,11,and 13 showed significant inhibition of NO production activity.Compounds 3,7,and 10-15 showed remarkable quinone reductase inducing activity.Four new compounds leptosphaerins H and I(22-23),leptosphins A and B(24 and 25),as well as 16 known compounds sphaeropsidone(26),2,5-dimethyl-7-hydroxychromone(27),(R)-(-)-O-methylmellein(28),6-hydroxymellein(29),2,3-dihydro-5-hydroxy-1H-2-isoindol-l-one(30),bis(2-ethylheptyl)phthalate(31),bis(2-ethyldecyl)phthalate(32),monomethyl-sulochrin(33),alternariol(34),n,butyl-2,4-dihydroxy-3,6-dimethylbenzoate(35),orselinic acid(36),vanillic acid(37),4-hydroxybenzoic acid(38),ethyl phenyl ether(39),(R)-2-ethylhexan-l-ol(40),and linoleic acid(41)were isolated from culture of one strain of endophytic fungi Leptosphaeria sp.L1201 inhabiting healthy tissues of the plant Casearia balansae Gagnep.Compound 34 showed moderate cytotoxic activity against the Hep G2 and Hela cancer cell lines.Compounds 24,34,and 35 showed significant inhibition of NO production activity.Compounds 25 and 36 showed remarkable quinone reductase inducing activity.