Methoxyflavone glucosides and caffeoyl phenylethanoid glycoside from Lysionotus pauciflorus: their structures and anti-ferroptosis activity.

Phytochemical investigation on the aerial parts of Lysionotus pauciflorus Maxim. (Gesneriaceae), a medicinal plant used in Guangxi Zhuang Autonomous Region, China, resulted in the isolation of 13 secondary metabolites including two methoxyflavones, six flavonoid glycosides, and five caffeoyl phenylethanoid glycosides. Among these, the chemical structures of previously undescribed metabolites (1-3) were elucidated to be nevadensin 7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranoside (1), nevadensin 7-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (2), and 2-(3,4-dihydroxyphenyl)ethyl-1-O-β-D-apiofuranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 3)-β-D-(6'-O-E-caffeoyl)glucopyranoside (3) by detailed spectroscopic and HPLC analyses. Inhibitory activity of isolated compounds against RSL3-induced ferroptosis on human hepatoma Hep3B cells were evaluated.