Figure 4

Quercetin and its glycosides protect PC12 cells from high glucose-mediated death. Exposure to glucose toxicity elicited a significant loss in cell viability compared to normal glucose conditions as assessed by mitochondrial dehydrogenase activity measured by cleavage of the formazan dye WST [left panel, ** denotes a significant difference (p < 0.01) relative to normal glucose control, Student’s t-test, n = 16]. Multiple concentrations of quercetin aglycone, hyperoside, isoquercetin (quercetin-3-O-glucoside), and rutin (quercetin-3-O-rutinoside), were administered to high glucose-treated cells to assess cytoprotective activity [right panel, coloured # and ## denote significant differences (p < 0.05 and ## p < 0.01, respectively) between high glucose control and similarly coloured samples, ANOVA, post-hoc Dunnett’s t-test, n = 8-10]. Data are reported as the mean ± SEM.