Caffeoylquinic acid esters, lignans and flavones from Yua thomsonii with cytotoxic and nitric oxide inhibitory activities

Abstract

Phytochemical study on the aerial parts of Yua thomsonii resulted in the isolation of 11 secondary metabolites, including a new caffeoyl quinic acid derivative, 3-O-trans-caffeoyl-4-O-acetylquinic acid methyl ester (1), a new dihydrobenzofuran neolignan, 3,5-dimethoxy-4-(1″,3″-dihydroxy-2″-propyloxyl)-4′,7-epoxy-8,5′-neolignan-4,9,9′-triol (3) and nine known compounds, methyl 4-O-coumaroylquinate (2), (7S*,8S*)-3-methoxy-3′,7-epoxy-8,4′-oxyneolignan-4,9,9′-triol (4), kompasinol A (5), lyoniresinol (6), schizandriside (7), (−)-isolariciresinol 3a-O-β-D-xylopyranoside (8), lyoniside (9), vitexin (10) and luteolin 4′-O-β-glucopyranoside (11). Their structures were elucidated using comprehensive spectroscopic methods, including 1D and 2D NMR and HRESI mass spectra. The absolute configurations of 1 and 3 were deduced by electronic circular dichroism spectroscopy. Compounds 1, 3, 5 and 6 exhibited nitric oxide (NO) inhibitory effects, with IC50 values ranging from 12.18 to 29.45 µM. However, compounds 1, 3, 6 and 8 were non-cytotoxic towards HepG2 and MCF-7 carcinoma cells.