Combined effect of total flavonoids from seed residues of Hippophae rhamnoides L. and zinc on advanced glycation end products-induced endothelial cell dysfunction

► Study on total flavonoids from seed residues of Hippophae rhamnoides L. (FSH). ► FSH and FSH-ZnCl2 restore the imbalance in cellular oxidative stress induced by AGEs. ► FSH and FSH-ZnCl2 elevate NO bioavailability by increasing cellular zinc levels. ► FSH-ZnCl2 plays a more effective role in elevating eNOS and NO levels than FSH does. ► The loss of zinc during FSH extraction is important to the efficacy of FSH in vitro.