Seimatoric acid and colletonoic acid: Two new compounds from the endophytic fungi, Seimatosporium sp. and Colletotrichum sp.

A new metabolite, named seimatoric acid (1), representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz., 2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone (2), (−)-phyllostine (3), (+)-epiepoxydon (4) and (+)-epoxydon monoacetate (5). Similarly one new benzoic acid derivative, named colletonoic acid (6) was isolated from the ethyl acetate fraction of Colletotrichum sp. The structures of the new compounds were elucidated by detailed 1H NMR, 13C NMR, COSY, HMQC, HMBC spectroscopic analysis, and HR-EI-MS. Seimatoric acid (1) was also isolated from another taxonomical unidentified fungal strain 4295 in our group. The structures of the known compounds were elucidated by their spectral data comparison to literature data. Preliminary studies showed that colletonoic acid (6) showed good antibacterial, antifungal, and antialgal activities.