Novel immunosuppressive pregnane glycosides from the leaves of Epigynum auritum

Abstract

Phytochemical investigation on the leaves of Epigynum auritum led to the isolation of three novel C₂₁ pregnane glycosides, epigynosides, E-G (1-3), together with two known pregnane glycosides, epigynosides A (4) and C (5). Their structures were elucidated based on extensive spectroscopic data (MS, IR, 1D and 2D NMR) analysis, as well as comparison with the reported data. The immunological activities of the new compounds was evaluated against concanavalin A (Con A)-stimulated proliferation of mice splenocyte in vitro. Compounds 1-3 displayed significant immunosuppressive activities, close to the efficacy of the positive control (dexamethasone) at the concentration of 50μM.

Keywords: Epigynosides E–G; Epigynum auritum; Immunosuppressive; Pregnane glycosides.