New steroid saponins from Dioscorea zingiberensis yam and their medicinal use against I/R via anti-inflammatory effect

Steroid saponins are the medicinal compounds and nutrition ingredients of medicine food homology (MFH) Dioscorea zingiberensis C. H. Wright (D. zingiberensis) yam. Our phytochemical investigation of the edible rhizomes resulted in 9 new furostanol steroid saponins named dioscins A-I (1-9), together with 11 known steroid saponins. Their chemical structures were elucidated based on spectroscopic and chemical analyses. The new dioscins were evaluated for their anti-inflammatory and beneficial effects against cerebral ischemia reperfusion (I/R) injury on RAW264.7 and PC12 cells in vitro, respectively. Dioscins A, B, and G revealed considerable anti-I/R effect through an anti-inflammatory mechanism based on the decreasing concentration of pro-inflammatory (TNF-α and IL-6) and down-regulating the NF-κB expression. The present research demonstrated that daily consumption of this yam plant probably prevented the I/R occurrence via the anti-inflammatory property of steroid saponins, and it also enriched the steroid saponin library, providing the possibility to develop MFH-containing steroid saponins into functional foods for maintenance of human health or drugs for the treatment of I/R disease.