Triterpenoid saponins from Clematis manshurica inhibiting the inflammatory responses of TNF-α-stimulated MH7A cells.

Ten previously undescribed oleanane-type triterpenoid saponins bearing a free C-28 carboxyl group (1-10) and 12 known compounds (11-22) were isolated from the roots and rhizomes of Clematis manshurica (Rupr.). The structures were determined via spectroscopy and chemical tests. All compounds were evaluated for their inhibitory effects against TNF-α-induced abnormal proliferation of MH7A cells. Compounds 2, 12, and 14-16 exhibited distinct inhibitory effects, with cell survival rates of 65.88%, 72.13%, 59.28%, 77.59%, and 75.81% at 5 μM, respectively. Preliminary structure-activity relationship analysis indicates that the free C-28 carboxyl group of the aglycone is essential for the observed activity. Further investigation of compound 2 reveals its ability to suppress TNF-α-induced proliferation, migration, and invasion of MH7A cells while promoting apoptosis. The results suggest that compounds 2, 12, and 14-16 can be potential anti-rheumatoid arthritis agents.