Steroidal glycosides from the roots of Cynanchum stauntonii and their effects on the expression of iNOS and COX-2

Abstract

Six new steroidal glycosides, named stauntosides O-T (1–6), along with eight known compounds (7–14), were obtained from the 95% aqueous ethanol extract of the roots of Cynanchum stauntonii. Their chemical structures were elucidated by IR, HR ESI-MS/MS, 1H- and 13C NMR, 1H-1H COSY, HSQC, HSQC-TOCSY, and HMBC spectroscopic analyses, which showed interesting 13,14:14,15-disecopregnane-type or 14,15-secopregnane-type C21 steroidal glycosides. The glycosides’ anti-inflammatory effects were investigated by detecting the inhibitory effects of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) on RAW246.7 murine macrophage cells stimulated by lipopolysaccharide (LPS). Our results showed that compounds 1, 5, 8, 9, 11, and 13 could significantly inhibit iNOS expression, and compounds 5 and 7 could clearly reduce COX-2 expression in RAW246.7 cells stimulated by LPS compared to cells stimulated with LPS and not treated with other compounds. Thus, compounds 1, 5, 7–9, 11, and 13 have the potential to mediate anti-inflammatory effects, with compound 5 having a greater anti-inflammatory effect than the other compounds.