Five new isocoumarin derivatives, pestalactone A-C (1-3) and pestapyrone D-E (4-5), together with two known compounds (6-7) were isolated from the solid cultures of the endophytic fungus Pestalotiopsis sp. obtained from Photinia frasery. Their structures were mainly determined by extensive spectroscopic analysis, Mo2(OCOCH3)4-induced electronic circular dichroism (ECD), and ECD calculation. Compounds 1 and 2 were rare isocoumarin derivatives and derived from distinctive polyketide pathways. Compound 3 exhibited potent antifungal activity against Candida glabrata (ATCC 90030) with an MIC50 value of 3.49±0.21μg/mL.
Keywords: Antifungal activity; Ethyl ethanoate (PubChem CID: 8857); Isocoumarin; Methanol (PubChem CID: 887); Methylene chloride (PubChem CID: 6344); Pestalotiopsis sp.; Petroleum ether (PubChem CID: 6013); Polyketide pathway.
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