New ursane-type triterpene with NO production suppressing activity from Nauclea officinalis.

Two new ursane-type triterpenes, named as 3β, 19α, 23, 24-tetrahydroxyurs-12-en-28-oic acid (1) and 2β, 3β, 19α, 24-tetrahydroxyurs-12-en-28-oic acid (2), together with two known triterpenoids, 3-oxo-urs-12-ene-27, 28-dioic acid (3) and quinovic acid-3-β-rhamnopyranoside (4), were isolated from the stems (with barks) of Nauclea officinalis. The structures of 1 and 2 were determined by the combined use of single-crystal X-ray diffraction and spectroscopic data analysis. The inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells were examined, and compound 1 was found to inhibit NO production, with the IC(50) value of 4.8 μM.