Three new polyketides from a mangrove-derived fungus Colletotrichum gloeosporioides

Three new polyketides, (2S)-2,3-dihydro-5,6-dihydroxy-2-methyl-4H-1-benzopyran-4-one (1), (2′R)-2-(2′-hydroxypropyl)-4-methoxyl-1,3-benzenediol (2), and 4-ethyl-3-hydroxy-6-propenyl-2H-pyran-2-one (3) were isolated from the culture broth of Colletotrichum gloeosporioides, an endophytic fungus derived from the mangrove Ceriops tagal. The structures of 1–3 were elucidated on the basis of NMR spectra and HR-ESI-MS data. Their absolute configurations were determined by comparing with the experimental and calculated ECD spectrum. Compounds 1 and 3 showed potent antibacterial activities against some of the tested microbes