Abstract: In the present study, the protective effects of flavonoids against metabolic syndrome (MS) in rats were investigated. Quercetin, kaempferol, and rutin were chosen because of their similar molecular structures. Rats were divided into five groups according to their diets: basal diet, high-fructose and high-fat diet (HFFD) (model group (MG)), HFFD with quercetin (2.6 mmol/kg mb), HFFD with kaempferol (2.6 mmol/kg mb), and HFFD with rutin (2.6 mmol/kg mb). Diet intervention lasted for 13 weeks. Serum biochemical indicators, hepatic antioxidant capacity, pro-inflammatory cytokines, and hepatic histological changes were determined. Quercetin significantly reduced the level of alanine transaminase to (25.00 ± 0.67) U/L compared with MG ((33.00 ± 0.67) U/L) (P < 0.05). Kaempferol was effective in reducing body mass gain and fat accumulation. The final body mass of kaempferol-treated rats decreased by 10.7% at average relative to MG. Rutin decreased the area under the curve (AUC) during oral glucose tolerance test (OGTT) from (13.80 ± 0.45) mmol/(L·min) in MG to (12.10 ± 0.13) mmol/(L·min) (P < 0.05). Dietary flavonoids can be used in the prevention of MS, but these compounds play different biological roles in spite of their similar structures.

Key words: flavonoids, metabolic syndrome, high-fat, high-fructose, diet