Inhibitory effects of oleanane-type triterpenes and saponins from the stem bark of Kalopanax pictus on LPS-stimulated pro-inflammatory cytokine production in bone marrow-derived dendritic cells.

Kalopanax pictus (Araliaceae) is a deciduous tree distributed in Korea, Japan, and China. The stem bark of K. pictus has been functionally used as a traditional crude drug for the treatment of various inflammatory diseases. In the present study, we describe the inhibitory effects of oleanane-type triterpenes and saponins isolated from the stem bark of K. pictus on production of pro-inflammatory cytokines in LPS-stimulated bone marrow-derived dendritic cells. Of the compounds tested, 16,23,29-trihydroxy-3-oxo-olean-12-en-28-oic acid (1), 4,23,29-trihydroxy-3,4-seco-olean-12-en-3-oate-28-oic acid (2), 3β,6β,23-trihydroxyolean-12-en-28-oic acid 28-O-β-D-glucopyranoside (3), nipponogenin E (6), 3β,6β,23-trihydroxyolean-12-en-28-oic acid (7), and caulophyllogenin (19) significantly inhibited the production of IL-12 p40 and IL-6 with IC50 values ranging from 3.3 to 9.1 μM. Compounds 2, 3, 7, and 19 significantly suppressed the secretion of TNF-α with IC50 ranging from 8.8 to 20.0 μM. These data provide scientific support for the use of K. pictus stem bark and its triterpene and saponin components in the inhibition of pro-inflammatory cytokine secretion, including IL-12 p40, IL-6, and TNF-α, and for prevention and treatment of inflammatory diseases.