Antioxidant-rich Tamarindus indica L. leaf extract reduced high-fat diet-induced obesity in rat through modulation of gene expression

Abstract

BackgroundDifferent parts of the medicinal plant Tamarindus indica L. are full of phytochemicals that are able to reduce elevated blood pressure, blood sugar and lipids. These pharmacological effects are due to the presence of antioxidant type compounds in those parts of the plant. This study was aimed to explore the molecular mechanism of anti-obesity effects of ethanolic extract of T. indica L. leaves (TILE) through the evaluation of biochemical parameters and gene expression analysis in high-fat diet (HFD) consuming Wistar rats.MethodsMale Wistar rats were supplied with a standard diet (SD), or HFD, or HFD with 100 mg/kg or 200 mg/kg or 400 mg/kg TILE for 8 weeks. The body weight, liver weight, fat weight, plasma lipids, and oxidative stress-related parameters were measured. The transcript levels of different adipogenesis related transcription factors, lipogenic enzymes, and lipolytic enzymes were also evaluated by quantitative real-time PCR.ResultPhytochemical analysis demonstrated that TILE is enriched with a substantial level of polyphenols (287.20 ± 9.21 mg GAE/g extract) and flavonoids (107.52 ± 11.12 mg QE/g extract) which might be the reason of significant antioxidant and radical scavenging activities. Feeding of TILE (400 mg/kg/day) to HFD-fed rats increased activity of superoxide dismutase and catalase which is reflected as a significant reduction of oxidative stress markers like nitric oxide and malondialdehyde. TILE (400 mg/kg/day) feeding also down-regulated the mRNA levels of proadipogenic transcription factors including liver X receptor alpha (LXRα), peroxisome proliferator-activated receptor gamma (PPARγ), and sterol regulatory element-binding protein 1c (SREBP1c) in diet-induced obese rats. As a consequence of this, the mRNA level of lipogenic enzymes like acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), diacylglycerol acyltransferase (DGAT), and HMG-CoA reductase was down-regulated with a parallel up-regulation of the transcript level of lipolytic enzyme, hormone-sensitive lipase (HSL).ConclusionObservations from this study indicate that antioxidant-rich TILE can reduce HFD-induced body weight, fat weight and liver weight as well as blood lipids through down-regulating the gene expression of proadipogenic transcription factors and lipogenic enzymes with a concerted diminution of the gene expression of lipolytic enzyme, HSL.