Anti-inflammatory <i>neo</i>-Clerodane Diterpenoids\nfrom <i>Ajuga pantantha</i>

Abstract

Eight new <i>neo</i>-clerodane\nditerpenoids (<b>1</b>–<b>8</b>) were acquired\nfrom the aerial parts of <i>Ajuga pantantha</i>. Spectroscopic\ndata analysis permitted the\ndefinition of their structures, and experimental and calculated electronic\ncircular dichroism data were used to define their absolute configurations.\nCompounds <b>2</b> and <b>4</b>–<b>8</b> were\nfound to have NO inhibitory effects with IC₅₀ values of\n20.2, 45.5, 34.0, 27.0, 45.0, and 25.8 μM, respectively. The\nmore potent compounds <b>2</b>, <b>6</b>, and <b>8</b> were analyzed to establish their anti-inflammatory mechanism, including\nregulation of the expression of inducible nitric oxide synthase (iNOS)\nand cyclooxygenase-2 (COX-2) proteins as well as their binding interactions\nwith the two proteins.