Naphthoquinones from Onosma paniculatum with Potential Anti-inflammatory Activity.

Four new naphthoquinones (1-4), including a dimeric one, shikometabolin G (1), together with six known ones (6-10), were isolated from the methanol extract of Onosma paniculatum. Their structures were established based on the analysis of NMR and MS spectroscopic data. All of the compounds were evaluated for inhibitory effects on NO production in murine macrophage RAW 264.7 cells. Compounds 2, 3, 5, 6, 7, 8, and 10 displayed good activity on the inhibition of NO production (IC50 = 0.4-16.5 µM), suggesting the potential property of anti-inflammation.