J Basic Clin Physiol Pharmacol 2017; aop Santosh Singh Bhadoriya*, Aditya Ganeshpurkar, Ravi Pratap Singh Bhadoriya, Sanjeev Kumar Sahu and Jay Ram Patel Antidiabetic potential of polyphenolic-rich fraction of Tamarindus indica seed coat in alloxan-induced diabetic rats https://doi.org/10.1515/jbcpp-2016-0193 Received December 27, 2016; accepted June 21, 2017 Abstract Background: Tamarindus is a monotypic genus and belongs to the subfamily Caesalpinioideae of the family Leguminosae (Fabaceae), Tamarindus indica L., com- monly known as Tamarind tree is one of the most impor- tant multipurpose tropical fruit tree species in the India, Sudan, Nigeria, Bangladesh and entire subcontinent. Methods: Hydroethanolic seed coat extract of Tama- rindus indica (HETI) was assessed for presence of phy- toconstituents and selection of optimum dose through acute and sub acute toxicity study. The single and multi- dose (14 days) study were conducted to evaluate anti- diabetic potential of HETI in alloxan induced rats via determine of blood glucose level, body weight, hema- tological profile, extra-pancreatic glucose utilization of isolated rat hemi-diaphragm as well as histopathology of rat pancreas. Results: Phytochemical analysis of HETI showed the pres- ence of polyphenol like flavonoids. Single and multidose of HETI significantly (p < 0.05; p < 0.001) reduced blood glucose level in normoglycaemic, glucose loaded and alloxan induced hyperglycaemic animals. HETI exerts the protective effect on pancreatic β-cells as per results obtained from histopathology of animals. Moreover, HETI increased glucose uptake in isolated rat hemi-diaphragm and prevents decrease in body weight along with recovery of altered hematological parameters. Conclusions: The study revealed that HETI have potent hypoglycaemic action by virtue of its Phytoconstituents and it can be used as a herbal medicine for diabetes. Keywords: Tamarindus indica; hydroethanolic seed coat; phytoconstituents; optimum dosage. Introduction Insulin is essential for maintaining glucose homoeo- stasis and regulating carbohydrate, lipid, and protein metabolism. An absolute or relative lack of insulin causes chronic metabolic disorder called diabetes mellitus (DM) [1]. DM is characterised by hyperglycaemia, hypertriglyc- eridaemia and hypercholesterolemia [2]. Insulin and oral hypoglycaemic agents that are currently used in clinical practise for the treatment of DM have severe side effects [3–6]. In recent times, some medicinal plants have been reported as possible alternatives for the treatment of dia- betes worldwide; they have also been used empirically as antihyperlipidemic remedies without any draw back like conventional therapy [7–10]. Tamarindus indica L. (Family: Leguminosae), com- monly known as tamarind, is one of the most important medicinal plants, widely found in the Indian sub-continent and tropical countries [11, 12]. It is used for the treatment of cold, dysentery, cough, sore throat, rheumatism, furun- cles, malaria, stomach disorder, diarrhoea, jaundice, and as skin cleanser [13]. In the traditional Indian system (i.e. Ayurveda), T. indica is used for the management of diabetes (Madhumeh) [14]. Therefore, the current study was under- taken to execute the antidiabetic effect of seed coat extract of T. indica in alloxan-induced diabetic rats. Together with the antihyperglycemic effect, an attempt had been made to confirm its safety through the determination of various biochemical and biophysical parameters. *Corresponding author: Santosh Singh Bhadoriya, Phytopharmacological Research Laboratory, Department of Pharmacology, Oriental College of Pharmacy, Bhopal, Madhya Pradesh 462021, India, Phone: +91 9098941416, E-mail: bhadoriya7@gmail.com; sanjeevsahu82@yahoo.co.in Aditya Ganeshpurkar: Department of Pharmacology, Shri Ram Institute of Technology, Jabalpur, Madhya Pradesh, India Ravi Pratap Singh Bhadoriya: Institute of Microbial Techniques and Culture, Council of Scientific and Industrial Research (CSIR), Chandigarh, India Sanjeev Kumar Sahu and Jay Ram Patel: Phytopharmacological Research Laboratory, Department of Pharmacology, Oriental College of Pharmacy, Bhopal, Madhya Pradesh, India