Studies On The Secondary Metabolites And Bioactivities Of Two Endophytic Fungal Strains Isolated From Mangrove Plants

Mangrove ecosystem is one of the important types of coastal zone as wetland ecosystem in China. The mangrove plants are enriched with variety of endophytic microbial flora in it which in turn produce numerous bioactive metabolites. Its endophytic fungi have unique metabolic pathways and genetic background. These mangroves derived endophytic fungi, now becoming the important source for producing new drug candidate.As an outstretch of this theme the present work envisaged the isolation of new bioactive secondary metabolites with novel structures and bioactives from two endophytic fungi derived from two different mangrove plants Aegiceras corniculatum and Kandelia candel.Eight compounds were isolated from the endophytic fungi NAc FL10 derived from mangrove plant Aegiceras corniculatum, which were grown over the solid rice as the culture medium. All their structures and absolute configurations were determined by extensive 1D-NMR, 2D-NMR, X-ray and other modern techniques. The compounds isolated are characterized to be: Leptosphaerin(G1), Dihydro-4-hydroxy-5-hyroxymethyl-2-furanone(G2), 5-hydroxymethyl furaldehyde(G3), 2,4-dihydroxy-3,5,6-trimethylbenzoate(G4), thymidine(G5), tyrosol(G6), ergosterol(G7), and dimethyl phthalate(G8).Three new compounds together with 22 known compounds were isolated from the fungi Botryosphaeria sp. SCSIO Kc F6 derived from the mangrove plant Kandelia candel. These compounds were identified as: Botryoisocoumarin A(K1), Botryosphaerin A(K2), Botryosphaerin B(K3), Orthosporin(K4), Monocerin(K5), physcion(K6), 6-methy-aloe-emodin(K7),(1R,2S,4S)-1,2,3,4-Tetrahydron-aphthalene-1,2,4,5-tetrol(K8),(1S,2S,4S)-1,2,3,4-Tetrahydronaphthalene-1,2,4,5-tetrol(K9),(1R,2S,4S)-4-methoxy-1,2,3,4-Tetrahydronaphthalene-1,2,5-triol(K10), regilolne(K11), 8-methoxymellein(K12), 5-hydroxy-7-methoxy-4-methylphthalide(K13),(R)-8-methoxy-3-methylisochroman-1-one(K14), 3-methyl-6,8-dihydroxyisocoumarin(K15),(3R,4S)-4,8-dihydroxy-3-methylisochroman-1-one(K16), 4-hydroxy-3-methoxybenzoicacid(K-17), methyl-3,4-dihydroxybenzoate(K18), 11-Epiterpestacin(K19), Fusaproliferin(K20), ergosterol-6,22-diene-5α,8α-epidioxy-3-ol(K21), 4-hydroxybenzaldehyde(K22), thymidine(K23), 2’-methoxyadenosine(K24), 5-methylbenzene-1,3-diol(K25).Compounds K1, K2 and K3 are new compounds, K8 and K9 are new natural products. The isolated compounds were evaluated for their cytotoxic, anti-inflammatory(COX-2) and antimicrobial activities. Compounds K1, K3 exhibited specific COX-2 inhibitory activity with the IC50 value of 6.15 μM and 1.12 μM, respectively.