Abstract
CONTEXT: Callistemon citrinus Skeels (Myrtaceae) exhibits many biological activities. OBJECTIVE: This study analyzes for the first time, the toxicity, obesogenic, and antioxidant effects of C. citrinus in rats fed with a high fat-fructose diet (HFFD). MATERIALS AND METHODS: Four studies using male Wistar rats were conducted: (a) 7 groups (n = 3): control (corn oil) and ethanol extract of C. citrinus leaf (single oral dose at 100-4000 mg/kg) for acute toxicity; (b) 2 groups (n = 8): control (corn oil) and C. citrinus (1000 mg/kg/day) for 28 days for subacute toxicity; (c) 3 groups (n = 4) with single oral dose of lipid emulsion: control (lipid emulsion), C. citrinus and orlistat (250 and 50 mg/kg, respectively) for lipid absorption; (d) 4 groups (n = 6): control (normal diet) and 3 groups fed with HFFD: HFFD only, C. citrinus and simvastatin (oral dose 250 and 3 mg/kg, respectively) for 13 weeks. Antioxidant enzymes and biomarkers were evaluated and inhibition of pancreatic lipase was determined in vitro. RESULTS: Toxicological studies of C. citrinus showed no differences in biochemical parameters and lethal dose (LD(50)) was higher than 4000 mg/kg. C. citrinus inhibited pancreatic lipase activity, with IC(50) of 392.00 µg/mL, and decreased lipid absorption by 70%. Additionally, it reduced the body weight 22%, restored the activities of antioxidant enzymes, and reduced the biomarkers of oxidative stress. CONCLUSIONS: Callistemon citrinus showed an effect against oxidative stress by reducing biomarkers and induced antioxidant system, without toxic effects.