Humulene Derivatives from Zingiber zerumbet with the Inhibitory Effects on Lipopolysaccharide-Induced Nitric Oxide Production

Abstract

A new humulene sesquiterpene, 5-hydroxyzerumbone (5-hydroxy-2E,6E,9E-humulatrien-8-one) (1) and a known compound, zerumboneoxide (2) were isolated from the rhizomes of Zingiber zerumbet (Zingiberaceae), and found to inhibit lipopolysaccharide-induced nitric oxide production in murine macrophage RAW 264.7 cells with IC₅₀ values of 14.1 and 23.5 μM, respectively, by bioassay-guided fractionation (positive control: N^ω-monomethyl-L-arginine, IC₅₀=21.3 μM). The structure of 1 was determined by spectroscopic methods including 1D and 2D-NMR.