Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2014, 6(2):679-682 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 679 HPAA inhibitory effect of embelin and its metal complexes on diabetic complications: An approach with molecular docking studies Saba Maanvizhi 1 , Radhakrishnan Narayanaswamy 2 , Lam Kok Wai 3 and Arumugam Gnanamani 4* 1 Faculty of Pharmacy, Sri Ramachandra University, Porur, Chennai, Tamil Nadu, India 2 Laboratory of Natural Products, Institute of Bioscience (IBS), Universiti Putra Malaysia (UPM), Serdang, Selangor, Malaysia 3 Faculty of Pharmacy, Universiti Kebangsaan Malaysia (UKM), Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia 4 Microbiology Division, Central Leather Research Institute, Adyar, Chennai, Tamil Nadu, India _____________________________________________________________________________________________ ABSTRACT The occurrence of diabetes mellitus in the world’s population is increasing every year. Most of the currently available synthetic therapeutic agents are associated with undesirable side effects. Moreover, inhibitors of pancreatic alpha-amylase are gaining much attention among the researchers owing to its therapeutic application in diabetic control and treatment. The primary objective of this study was to investigate the docking behaviour of human pancreatic alpha-amylase (HPAA) with Embelin, Vilangin, 5-O-methyl embelin, Quercetin, Metformin, Copper & Zinc embelin complexes and studying their putative binding sites using Discovery Studio Version 3.1. Docking studies and binding free energy calculations revealed that Zinc-embelin complex has maximum interaction energy (-44.6 kcal/mol) and Metformin with the least interaction energy (-13.1 kcal/mol) as compared to the other investigated ligands. Interestingly, Copper-embelin complex fails to dock with that of human pancreatic alpha amylase. Therefore, it is strongly suggested that the present study outcomes might provide new insight in understanding these six ligands, as potential candidates for human pancreatic alpha-amylase inhibitory activity. Keywords: Diabetes mellitus, Herbal Ligands, Inhibitors, Docking,Metal Complexes _____________________________________________________________________________________________ INTRODUCTION More than 80% of the population of our country is dependent on medicinal plants for its primary health care.Embeliaribes commonly known as Vidanga,is a highly valuable medicinal plant with various pharmacological activities [1]. The plant Embeliaribes(Myrsinaceae)contains embelin, quercitol, and fatty ingredients; an alkaloid, christembine, a resinoid, tannins and minute quantities of a volatile oil [2-4].Embelin was isolated from Embeliaribes berries and one of the major attractions among researchers towards quinone compounds is their color and biological activities [5]. Bhandari and co-workers [6-7] have reported the antidiabetic, antidyslipidemic and antioxidant activity of EmbeliaribesBurmin streptozotocin-induced diabetes in rats, using gliclazide as the positive control drug. In our earlier studies, we reported the antimicrobial [8] and UVB inhibitory activity of embelin [9]. Similarly, embelin has been reported to bind with collagen [10], tyrosinase [11], human neutrophil elastase [12] and human glutamate pyruvate transaminase [13] using molecular docking studies. Diabetes mellitus [14] is a chronic metabolic disease affected a wide range of population all over the world and leads to development of many severe long term complications.Family history, genetic makeup, low muscle or body activity, junk food or unhealthy diet, and excess body weight usually increase the risk of a person getting affected with stress and diabetes [15]. Some of the long-term symptoms include deterioration of normal health, atherosclerosis, myocardial infarction and hyperosmolar nonketotic diabetic coma [16]. So Diabetes mellitus is one