A new anti-inflammatory monoterpenoid indole alkaloid from the trunk of <i>Nauclea officinalis</i>

Two monoterpenoid indole alkaloids including one undescribed alkaloid, naucleficine B (<b>1</b>), and a known alkaloid glycoside, strictosamide (<b>2</b>) were isolated from ethyl acetate fraction of the 95% ethanol extract from the trunk of <i>Nauclea officinalis</i>, together with three known non-alkaloid components, (+)-medioresinol (<b>3</b>), protocatechuic acid (<b>4</b>), and benzoic acid (<b>5</b>). Their structures were elucidated on the basis of extensive spectroscopic analysis and X-ray diffraction. Compounds <b>1</b> and <b>2</b> exhibited potent anti-inflammatory effects in cigarette smoke extract (CSE)-stimulated RAW 264.7 and THP-1 macrophages. These compounds significantly suppressed nitric oxide (NO) generation, reduced the secretion of inflammatory mediators, and inhibited the activation of inflammation-related proteins.