Two new cyclohexene derivatives colletotricones A and B (1 and 2) and a new thiazole derivative colletotricole A (5), along with six known natural metabolites were isolated from the extract of Colletotrichum gloeosporioides A12, an endophytic fungus derived from Aquilaria sinensis. Among them, the colletotricones A and B possess a cyclohexenone skeleton, whereas the colletotricole A is a thiazole derivative. Their structures were fully assigned with the aid of extensive spectroscopic analysis and data from the literature. Moreover, cytotoxic activity in vitro of compounds 1 and 3-9 were evaluated against MCF-7, NCI-H460, HepG-2 and SF-268 tumour cell lines. The new compound 1 exhibited growth inhibitory activity against all the four tumour cell lines with IC50 values ranging from 15.7 to 46.8 μM.
Keywords: Aquilaria sinensis; Colletotrichum gloeosporioides; cyclohexene derivative; cytotoxicity; thiazole.