Naphthoquinone and flavonoid constituents from the carnivorous plant Nepenthes mirabilis and their anti-osteoporotic and antioxidant activities

摘要

The methanolic extract of Nepenthes mirabilis (Nepenthaceae) showed significant in vitro antioxidant (peroxyl radical-scavenging and reducing effects) and anti-osteoporotic (pre-osteoclastic RAW 264.7 cells) activities. Phytochemical investigation of chloroform and ethyl acetate partitions of N. mirabilis branches and leaves allowed to isolate 13 compounds (1-13), including two new naphthoquinones, nepenthones F (1) and G (2), together with 11 known compounds. The structures of the isolated compounds were established mainly by extensive analysis of the 1D and 2D NMR, as well as HRMS data. The isolated compounds also were further evaluated for in vitro antioxidant and anti-osteoclast activities. Among them, compounds 10 and 11 showed potent antioxidant effects. While compounds 4 and 12 showed significant inhibition on receptor activation for nuclear factor kappa B ligand (RAN kappa L)-induced osteoclast formation in murine bone-marrow macrophages. (C) 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.