Polyoxypregnane Glycosides from Root of Marsdenia tenacissima and Inhibited Nitric Oxide Levels in LPS Stimulated RAW 264.7 Cells

Six new polyoxypregnane glycosides, marstenacisside F1–F3 (1–3), G1–G2 (4–5) and H1 (6), as well as 3-O-β-D-glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1→4)-β-D-oleandropyranosyl-11α,12β-di-O-benzoyl-tenacigenin B (7), were isolated from the roots of Marsdenia tenacissima. Their structures were established by an extensive interpretation of their 1D and 2D NMR and HRESIMS data. Compounds 1–7 were tenacigenin B derivatives with an oligosaccharide chain at C-3. This was the first time that compound 7 had been isolated from the title plant and its (1)H and (13)C NMR data were reported. Compounds 4 and 5 were the first examples of C(21) steroid glycoside bearing unique β-glucopyranosyl-(1→4)-β-glucopyranose sugar moiety. All the isolated compounds were evaluated for anti-inflammatory activity by inhibiting nitric oxide (NO) production in the lipopolysaccharide-induced RAW 264.7 cells. The results showed that marstenacisside F1 and F2 exhibited significant NO inhibitory activity with an inhibition rate of 48.19 ± 4.14% and 70.33 ± 5.39%, respectively, at 40 μM, approximately equal to the positive control (L-NMMA, 68.03 ± 0.72%).