ORIGINAL PAPER Antiobesity effect of Tamarindus indica L. pulp aqueous extract in high-fat diet-induced obese rats Khairunnuur Fairuz Azman • Zulkhairi Amom • Azrina Azlan • Norhaizan Mohd Esa • Rasadah Mat Ali • Zamree Md Shah • Khairul Kamilah Abdul Kadir Received: 17 July 2011 / Accepted: 22 September 2011 Ó The Japanese Society of Pharmacognosy and Springer 2011 Abstract Obesity and overweight are associated with atherosclerosis, fatty liver, hyperlipemia, diabetes mellitus, and various types of cancer. The global prevalence of overweight and obesity has reached epidemic proportions. Here, we investigated the effect of Tamarindus indica pulp aqueous extract (TIE) in diet-induced obese Sprague– Dawley rats. The animals were divided into five groups and labeled as follows: the normal control (NC) group received normal diet; the positive control (PC) group received high- fat diet; and the TIE 5, 25, and 50 groups, after the induction of obesity via a high-fat diet, received TIE at 5, 25, or 50 mg/kg orally for 10 weeks. It was observed that TIE decreased the levels of plasma total cholesterol, low- density lipoprotein (LDL), and triglyceride, and increased high-density lipoprotein (HDL), with the concomitant reduction of body weight. Moreover, TIE decreased plasma leptin and reduced fatty acid synthase (FAS) activity and enhanced the efficiency of the antioxidant defense system. TIE exhibits antiobesity effects, as indicated by a significant reduction in adipose tissue weights, as well as lowering the degree of hepatic steatosis in the obesity- induced rats. The extract possesses hepatoprotective activity, as it reversed the plasma liver enzymes level elevation prior to the high-fat diet. In conclusion, TIE improved obesity-related parameters in blood, liver, and adipose tissue in a rat model and suppressed obesity induced by a high-fat diet, possibly by regulating lipid metabolism and lowering plasma leptin and FAS levels. A dose-dependant effect of TIE is detected, where TIE at 50 mg/kg showed the most prominent effect, followed by TIE at 25 mg/kg and, subsequently, 5 mg/kg. Keywords Antioxidants Á Hypolipidemic Á Lipid peroxidation Á Tamarind Á Weight loss Introduction Obesity is correlated with various comorbidities, among which the most relevant are dyslipidemia [1], diabetes mellitus [2], fatty liver [3], and cardiovascular diseases, such as heart failure [4]. Although the etiology of obesity is complex, dietary factors, particularly the consumption of high-fat diet, are considered as major risk factors for its development [5]. The consumption of high-fat diet led to obesity because it facilitates the development of a positive energy balance, leading to an increase in visceral fat deposition; this led to abdominal obesity in particular [6]. Obesity prevalence has reached global epidemic pro- portions [7] not only in industrialized countries, but has radiated its effect to developing countries, including Malaysia. The Third National Health and Morbidity Survey (NHMS III) conducted in 2006 estimates that about 29.7% of males and 28.6% of females in the country are over- weight [body mass index (BMI) between 25.0 and 29.9], K. F. Azman Á Z. Amom (&) Phytomedicine Research Group, Department of Human Anatomy, Division of Physiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM, 43400 Serdang, Selangor, Malaysia e-mail: fradical@medic.upm.edu.my A. Azlan Á N. M. Esa Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM, Serdang, Selangor, Malaysia R. M. Ali Á Z. M. Shah Á K. K. A. Kadir Herbal Technology Center, Forest Research Institute of Malaysia, Kepong, Kuala Lumpur, Malaysia 123 J Nat Med DOI 10.1007/s11418-011-0597-8