Epigynumgenane-type pregnane glycosides from Epigynum cochinchinensis and their immunosuppressive activity.

Five undescribed C21 pregnane glycosides, epigycosides D-H, together with four known analogues, two lignans, and a flavonoid have been isolated from the stems of Epigynum cochinchinensis. The structures of pregnane glycosides were elucidated using spectroscopic techniques and acid hydrolysis. The in vitro immunological activities were assessed against Con A-stimulated proliferation of mice splenocytes. The C21 pregnane glycosides showed immunosuppressive activity in a concentration-dependent manner. Moreover, epigycoside E exhibited a potent immunosuppressive effect, and the IC50 value on Con A-stimulated mice splenocytes was 22.1 ± 6.4 μM. Epigycoside E also caused G0/G1 arrest, and inhibited TNF-α and IL-2 production.