Comparison of immunosuppressive activity of Stephanoside E and its aglycone from Stephanotis mucronata in vitro

Stephanoside E (STE) and its aglycone Stephanthraniline A (STA) isolated from the stems of Stephanotis mucronata (Blanco) Merr. were evaluated for their suppressive potentials on Th1 and Th2 immune responses in vitro, and the effects of the C-3 sugar chains on their activities were discussed. STE and STA significantly inhibited Con A and LPS-induced splenocyte proliferation, and reduced the production of Th1/Th2 cytokines (IL-2, IFN-γ, IL-4, and IL-10) from Con A-stimulated splenocytes in a concentration-dependent manner. The mRNA expression levels of Th1/Th2 cytokines (IL-2, IFN-γ, IL-4, and IL-10) and transcription factors (T-bet and GATA-3) in Con A-stimulated splenocytes were also suppressed by STE and STA. The suppressive effect of STA on Th1 and Th2 immune responses in vitro was stronger than that of STE. These findings suggested that both STE and STA could simultaneously inhibit Th1/Th2 immune responses, and the glycosyl formation at the position C-3 of STA could decrease the immunosuppressive activity in vitro.