Chemical investigation of the lichen Parmotrema indicum Hale led to the isolation of one new diphenyl ether, parmetherine D (1), along with eight known compounds (2-9). The structures were determined by analysis of MS and NMR data and by comparison with the literature. Compounds 1, 2, and 7 were evaluated for α-glucosidase inhibition. Only compound 1 exhibited significant inhibition.[Formula: see text].
Keywords: Lichen; Parmotrema indicum Hale; diphenyl ether; parmetherine D; α-glucosidase inhibition.