Beneficial Effects of Bauhinia rufa Leaves on Oxidative Stress, Prevention, and Treatment of Obesity in High-Fat Diet-Fed C57BL/6 Mice

Abstract

Obesity is an epidemic disease worldwide, associated with oxidative stress and the development of several other diseases. Bauhinia rufa (Bong.) Steud. is a native Brazilian Cerrado medicinal plant popularly used for the treatment of obesity. In this context, we investigated the chemical composition of the methanolic extract of B. rufa leaves (MEBr) and evaluated the antioxidant activity and its impact on the prevention and treatment of obesity in mice fed a high-fat diet (HFD 60%). Additionally, the acute oral toxicity of MEBr was evaluated. In MEBr, 17 glycosylated compounds were identified, including myricetin, quercetin, kaempferol, coumaroyl, cyanoglucoside, and megastigmane. In vitro, MEBr showed antioxidant activity in different methods: DPPH^•, ABTS^•+, FRAP, iron-reducing power, inhibition of β-carotene bleaching, and inhibition of DNA fragmentation. In human erythrocytes, MEBr increased the activities of antioxidant enzymes, superoxide dismutase, and catalase. Under oxidative stress, MEBr reduced oxidative hemolysis, and the malondialdehyde (MDA) levels generated in erythrocytes. Mice treated acutely with MEBr (2000 mg/kg) showed no signs of toxicity. During 90 days, the mice received water or MEBr simultaneously with HFD for induction of obesity. At this stage, MEBr was able to reduce the gain of subcutaneous white adipose tissue (WAT) and prevent the increase of MDA in the heart and brain. After 180 days of HFD for obesity induction, mice that received MEBr simultaneously with HFD (HFD-MEBr) in the last 60 days of treatment (120-180 days) showed a reduction of retroperitoneal and mesenteric WAT deposits and MDA levels in the heart, liver, kidney, and brain, compared to the HFD-Control group. These effects of MEBr were similar to mice treated with sibutramine (HFD-Sibutramine, 2 mg/kg). Combined, the results show that compounds from the leaves of B. rufa affect controlling oxidative stress and actions in the prevention and treatment of obesity. Thus, associated oxidative stress reduction and body composition modulation, in obese people, can contribute to the prevention of obesity-related comorbidities and improve quality of life.

Figure 1

Effect of methanolic extract of B. rufa leaves (MEBr) on DNA fragmentation induced by hydrogen peroxide (H₂O₂) and ultraviolet (UV) light. (a) Percentage of DNA integrity and (b) representative image of plasmid DNA fragmentation ((a) pcDNA 3.1: plasmid cloning DNA). Values are expressed as mean ± SEM. ^#P < 0.05 versus MEBr 0 μg/ml; ^∗∗∗P < 0.001 versus MEBr 0 μg/ml+H₂O₂+UV.

Figure 2

Effect of methanol extract of B. rufa leaves (MEBr) in human erythrocytes. (a) Superoxide dismutase (SOD), (b) catalase (CAT), and (c) glutathione peroxidase (GPx) enzymes, (d) hemolysis, (e) hemolysis induced by AAPH, and (f) MDA levels. AAPH: azobis(2-methylpropionamidine) dihydrochloride. Values are expressed as mean ± SEM. ^∗P < 0.05; ^∗∗P < 0.01; ^∗∗∗P < 0.001 versus MEBr 0 μg/ml (control).

Figure 3

Effect of methanol extract of B. rufa leaves (MEBr) in C57Bl/6 mice. (a) Evolution of body mass, (b) white adipose tissue deposits, and (c) malondialdehyde (MDA) generation in organs in mice fed with HFD simultaneously with water (HFD-Control) or MEBr, 200 mg/kg (HFD-MEBr), for 90 days. Standard control (SD-Control): mice received a standard diet and water for 90 days. Values are expressed as mean ± SEM. N = 10 mice per group. ^#P < 0.05 versus SD-Control; ^∗P < 0.05 versus HFD-Control.

Figure 4

Effect of methanol extract of B. rufa leaves (MEBr) in C57Bl/6 mice. (a) Evolution of body mass, (b) white adipose tissue deposits, and (c) malondialdehyde (MDA) generation in organs in mice fed with HFD for 120 days to induce obesity. After this period, the mice received HFD concurrently with water (HFD-Control); sibutramine, 2 mg/kg (HFD-Sibutramine); or MEBr, 200 mg/kg (HFD-MEBr) for 60 days (120-180 days). Standard control (SD-Control): mice received a standard diet for 120 days; after this period, mice received water simultaneously, for 60 days (120-180 days). Values are expressed as mean ± SEM. N = 10 mice per group. ^#P < 0.05 versus SD-Control; ^∗P < 0.05 versus HFD-Control.