Three new immunomodulating C21-steroidal glycosides from the stems of Stephanotis mucronata

Three new C(21)-steroidal glycosides stemucronatosides H, I, and J (1-3, resp.) were isolated from the stems of Stephanotis mucronata, together with three known compounds sinomarinoside A (4), sinomarinoside E (5), and stephanoside H (6). These isolated compounds were tested for their immunological activities in vitro against concanavalin-A(Con A)- and lipopolysaccharide(LPS)-induced proliferation of mice splenocytes. Compounds 3, 4, and 6 showed immunosuppressive activities in a dose-dependent manner, while compounds 1, 2, and 5 possessed immunoenhancing activities.