Isolation, Characterization, and NO Inhibitory Activities of Sesquiterpenes from Blumea balsamifera

Blumea balsamifera belongs to the family Compositae, and its leaves have been used as a flavoring ingredient and a tea. A phytochemical investigation of the aerial parts of B. balsamifera led to the isolation of 10 new (<b>1</b>–<b>10</b>) and 1 known (<b>11</b>) sesquiterpenes. Their structures were elucidated on the basis of extensive one- and two-dimensional nuclear magnetic resonance (heteronuclear multiple-quantum coherence, heteronuclear multiple-bond correlation, ¹H–¹H correlation spectroscopy, and nuclear Overhauser effect spectrometry) spectroscopic data analyses, and the structure of compound <b>1</b> was confirmed by X-ray crystallography. The inhibitory activities on lipopolysaccharide-induced NO production in murine microglial BV-2 cells of these sesquiterpenes were evaluated, and all of the compounds showed inhibitory effects