Perillanolides A and B, new monoterpene glycosides from the leaves of Perilla frutescens

Two new monoterpene glycosides, perillanolides A and B, together with a known compound reported from the genus Perilla for the first time were isolated and characterized from the leaves of Perilla frutescens (L.) Britton, Lamiaceae, a garnish and colorant for foods as well as commonly used for traditional medicine. The structures of the isolated compounds were elucidated on the basis of extensive spectroscopic evidences derived from nuclear magnetic resonance experiments, mass spectrometry and by comparing their physical and spectroscopic data of literature. These compounds, together with the previously isolated secondary metabolites of this species, were investigated for their inhibitory effects on xanthine oxidase in vitro. Of the compounds, luteolin showed the strongest inhibitory activity with an IC50 value of 2.18 mu M. Esculetin and scutellarein moderately inhibited the enzyme, while perillanolides A and B, and 4-(3,4-dihydroxybenzoyloxymethyl)phenyl-O-beta-d-glucopyranoside exerted weak activities. (C) 2017 Sociedade Brasileira de Farmacognosia. Published by Elsevier Editora Ltda.