Effects of HCE75, the standardized flavonoid mixture containing equivalent rutin, hesperidin, quercetin, and quercitrin doses and the fixed-ratio combination of rutin and hesperidin (75:21.5, w/w), on (A) immobility time in TST and (B to D) their respective line crossings in OFT. The mice were tested 1 h after administration (p.o.) of the vehicle (physiological saline with 10% Tween 80), fluoxetine (20 mg/kg), HCE75 (20, 200, 400, 800, and 1600 mg/kg), standardized flavonoid mixtures (0.4, 4, 8, 16, and 32 mg/kg), and the fixed-ratio rutin and hesperidin combination (0.4, 4, 8, 16, and 32 mg/kg). Data are expressed as mean ± S.E.M. (n = 10). Data were analyzed using one-way ANOVA for multiple comparisons, followed by post hoc Student–Newman–Keuls test. *p < 0.05, **p < 0.01, and ***p < 0.001 compared with the control group (vehicle); ##p < 0.01 and ###p < 0.001 compared with the positive reference group (fluoxetine).