Kalshinoids A–F, Anti-inflammatory Sesquiterpenes from <i>Kalimeris shimadae</i>

Abstract

In a study of the potential anti-inflammatory constituents from <i>Kalimeris shimadae</i>, six new sesquiterpenes, kalshinoids A-F (<b>1</b>-<b>6</b>), together with 21 known compounds (<b>7</b>-<b>27</b>), were isolated. The structures and absolute configurations of the new compounds were discerned from extensive spectroscopic analysis, and the absolute configurations of kalshinoids A, B, E, and F were established by ECD calculations. Furthermore, the identified compounds were tested for anti-inflammatory activity as assessed by inhibition of tumor necrosis factor-alpha (TNF-α) in THP-1 cells. Three sesquiterpenes [kalshinoid F, 4(15)-eudesmen-1β,7,11-triol, and 4α,10α,11-trihydroxy-1β<i>H</i>,5β<i>H</i>-guai-7(8)-ene] reduced levels of TNF-α in lipopolysaccharide-stimulated THP-1 cells in a concentration-dependent manner and were more potent than dexamethasone. These natural sesquiterpenes merit further investigation as possible anti-inflammatory agents.