Structural characterization and immunosuppressive activity of a new pregnane glycoside from <i>Epigynum cochinchinensis</i>

<p>Phytochemical investigation on the ethyl acetate fraction of the leaves of <i>Epigynum cochinchinensis</i> led to the isolation of a new C₂₁ pregnane glycoside, epigycoside B (<b>1</b>), together with three known analogues. Their structures were elucidated on the basis of extensive spectroscopic techniques, including UV, MS, and NMR experiments, as well as the chemical methods. Compound <b>1</b> displayed <i>in vitro</i> immunosuppressive activity against concanavalin A (Con A)/Lipopolysaccharides (LPS)-stimulated proliferation of mice splenocyte. The activity was significant as compared with control group at 50 <i>μ</i>M concentration.