Lignans from the seeds of Herpetospermum pedunculosum and their farnesoid X receptor-activating effect

Abstract

The seeds of Herpetospermum pedunculosum (Ser.) C.B. Clarke, a well-known Tibetan medicine in China, are rich in kinds of bioactive lignans. In this phytochemical investigation on H. pedunculosum, sixteen undescribed lignans, named as herpedulins A - P together with 24 known ones were isolated from the ethyl acetate extract of its seeds. Their structures including the absolute configurations were determined by HR MS, 1D and 2D NMR experiments, and comparison of their experimental ECD spectra with calculated ones or literature data. High content screening experiments revealed that 9 compounds could promote the expression of farnesoid X receptor in guggulsterone-induced human normal liver cells L02 cells significantly. Further molecular docking results demonstrated that herpedulin E, J and K exhibited best docking scores (9.70, 9.28 and 10.31, respectively). Hydrogen bonding and hydrophobic interactions might contribute to the main interaction of active compounds with FXR.

Keywords: Cucurbitaceae; FXR-Activating effect; Herpetospermum pedunculosum; Lignan; Molecular docking.