Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2016, 8(1):729-732 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 729 Improvement in binding affinity of Ginkgolide B in comparison to Levodopa: A molecular docking Study Rumpa Banerjee 1 , Riya Adhya 1 and Abhimanyu Thakur 2* 1 Department of Pharmaceutical Chemistry, Bharat Technology, Uluberia, Howrah, India 2 Department of Biomedical Sciences, City University of Hong Kong, 83, Tat Chee Avenue, Hong Kong SAR _____________________________________________________________________________________________ ABSTRACT Parkinson’s disease involves the malfunction and death of vital nerve cells in the brain called neuron which produce dopamine, a chemical that sends message to the part of the brain that controls movement and coordination. As Parkinson’s disease progresses, the amount of dopamine produced in the brain decreases, leaving a person unable to control movement normally. The test drug Ginkgolide B and standard drug Levodopa have targeted the protein D 2 receptor (PDB ID: 2YOU) and protein D 3 receptor (PDB ID: 3PBL) respectively. Both the test and standard drug were drawn using Chemsketch draw software and structures were optimized using Arguslab software. Then they were docked with the Dopamine D 2 protein (PDB ID: 2YOU) and Dopamine D 3 protein (PDB ID: 3PBL) using HEX software. The test drug showed improvement in binding affinity and other properties in comparison to standard drug. Keywords: Parkinson’s disease, 2YOU, 3PBL, Hex docking, Chemsketch. _____________________________________________________________________________________________ INTRODUCTION Parkinson’s disease is a progressive disease of the nervous system marked by tremor, muscular rigidity, and slow, unfocused movement, chiefly affecting middle-aged and elderly people. It is associated with degeneration of the basal ganglia of the brain and a deficiency of the neurotransmitter dopamine [1]. Levodopa is the most effective medicine to control the symptoms of Parkinson’s disease. Dopamine receptors are a class of G-protein coupled receptors that are prominent in the central nervous system. The two types of dopamine receptors are D 1 like and D 2 like. D 1 like receptors includes D 1 and D 5 receptors which are associated with stimulation of adenylate cyclase and D 2 like receptors includes D 2, D 3 , D 4, receptors subtypes which are associated with inhibition of adyenylate cyclise [2]. Ginkgo biloba is found in China, useful for dementia, Alzheimer’s and Parkinson’s disease [1-3]. Active ingredients in ginkgo leaves include flavonol glycosides and terpene trilactones, principally the diterpene ginkgolides A, B, C and J, and the sesquiterpene bilobalide, along with smaller amounts of biflavones, proanthocyanidins, and organic acids [4-6]. Docking is a method by which we can predict the preferred orientation, affinity and activity of a molecule to a targeted protein. The molecular docking tool, Hex 5.1 interface was used for docking and scoring [7-9]. The Protein Data Bank (PDB) file of the structure of ligand was done by using chemsketch draw software and the structure was optimized by using ArgusLab software. The optimized structure was used for molecular docking. The crystal structure of the protein that is the receptor was downloaded from PDB [9-14].