Pentacyclic triterpenoids from Cyclocarya paliurus and their antioxidant activities in FFA-induced HepG2 steatosis cells.

Six undescribed pentacyclic triterpenoids including four triterpenoid aglycones, 1β,2a,3β,23-tetrahydroxyurs-12-en-28-ursolic acid, 2a,3a,6β,19α,23-pentahydroxyurs-12-en-28-ursolic acid, 2α,3α,20β,23-tetrahydroxyurs-12-en-28-ursolic acid and 1β,2a,3β,23-tetrahydroxyurs-12,20(30)-dien-28-ursolic acid, and two triterpenoid glucosides, 2a,3a,23-trihydroxy-12,20(30)-dien-28-ursolic acid 28-O-β-d-glucopyranoside and 1-oxo-3β,23-dihydroxyolean-12-en-28-oic acid 28-O-β-d-xylopyranoside, along with 5 known triterpenoids were isolated from a CH3Cl-soluble extract of the leaves of Cyclocarya paliurus. Their structures were established on the basis of chemical and spectroscopic approaches. These compounds were assessed for their antioxidant effects on FFA-induced hepatic steatosis in HepG2 cells. The results revealed that three saponins and two aglycones markedly increased SOD activity and reduced MDA level.