A pair of new neo-clerodane diterpenoid epimers from the roots of Croton crassifolius and their anti-inflammatory.

A pair of new neo-clerodane diterpenoid epimers, 3S-methoxyl-teucvin (1) and 3R-methoxyl-teucvin (2), were isolated from the Roots of Croton crassifolius. Their structures were completely established on the basis of spectroscopic methods, and the absolute configurations were determined by analysis of electronic circular dichroism (ECD) spectroscopy and X-ray diffraction analysis. Compounds 1 and 2 exhibited anti-inflammatory activities with IC₅₀ values of 0.82 and 0.54 μM, respectively, while the IC₅₀ value of dexamethasone as a positive control was found to be 0.14 μM.