Pharmacogn. Commn. 2020;10(3):134-135. A multifaceted peer reviewed journal in the feld of Pharmacognosy and Natural Products www.phcogcommn.org Research Article Pharmacognosy Communications, Vol 10, Issue 3, Jul-Sep, 2020 134 ABSTRACT Introduction: Azadirachta indica is commonly known as Neem, is found abundantly in India. This plant is used in the treatment of infections, pain and wounds. Methods: The aim of present study to investigate in silico molecular docking study used for three phytoconstituents β-sitosterol(22,23-Dihydrostigmasterol, Stigmast-5-en-3-ol, β-Sitosterin), isomeldenin and nimbandiol from Azadirachtaindica to identify whether these compounds interact with the COX-2 and NOs. The structure of neem constituents were downloaded from Pubchem and structure of enzymes/ proteins were obtained from protein data bank. Results: Among all the compounds β-sitosterol and nimbandiol showed best docking score. Conclusion: Further cell culture-based studies might ensure the interaction of these constituents with COX-2 and NOs. Key words: Neem, Docking COX-2, NOs, Azadirachta indica is, Infections, Pain, β-sitosterol, Isomeldenin, Nimbandiol. Correspondence: Dr. Aditya Ganeshpurkar Assistant Professor, Shri Ram Institute of Technology- Pharmacy, Jabalpur-482002, Madhya Pradesh, INDIA. Phone no: +91 0761-4041266 E-mail: adityaganeshpurkar@gmail.com DOI: 10.5530/pc.2020.3.26 Sambhav Jain, Aditya Ganeshpurkar*, Nazneen Dubey Shri Ram Institute of Technology-Pharmacy, Jabalpur, Madhya Pradesh, INDIA. Molecular Docking of some Neem Constituents with COX-2 and NOs: An in silico Study INTRODUCTION Te cyclo-oxygenase is a principal isoenzyme associated with biosynthesis of thromboxane and prostaglandins. Prostaglandins are autacoids which play vital role in various physiological and pathological events. Te COX-1 is expressed in many tissues viz. stomach, kidney, brain, lungs, spleen etc., whereas, COX-2 is an inducible enzyme which is expressed during damage to tissues. Te use of analgesics is associated with renal and gastrointestinal toxicities (due to COX-1 inhibition) which restrict the use of potent analgesics during pain and infammation. Nitric oxide is a cell signaling entity which is known to induce infammation. Te biosynthesis of NO is due to activity of nitric oxide synthase enzyme. Tis enzyme bio transforms arginine into citrulline, as a result, NO is produced. NO is associated with over-expression of immune response by cytokine activated macrophages. Te adverse efects associated with overproduction of NO include infammation, vasoconstriction and tissue damage. NO is responsible for pathogenesis of infammatory disorders of the gut, lungs and joint. Man has been using medicine in form of herbs since ancient times. 1 Ayurveda includes compilation of bioactive herbs found in Indian sub- continent. Te method of preparation doses and precautions are also mentioned for usage of these herbs. 2 Neem (Azadirachta indica ) is native to India, Sri Lanka, Nepal and Bangladesh. It is well recognized for its various medicinal properties like antibacterial, antifungal, antidiabetic, sedative and contraceptive efect. 3 Neem is also associated with a dose dependent analgesic efect in experimental animal model. Te mechanism of analgesic efect seems to be mediated by central as well as peripheral efects. 4,5 Te present study aims to study in silico interactions of some Neem constituents with COX-2 and NOs enzymes. Experimental Software Python 2.7- language was downloaded from www.python.com, Molecular graphics laboratory (MGL) tools and AutoDock 4.2 was downloaded from www.scripps.edu, Discovery Studio visualizer 4.1 was downloaded from www.accelerys.com. Docking studies Molecular docking was performed on Neem phytochemicals (β-sitosterol, isomeldenin and nimbandiol) against COX-2 and NOs. Te structures of these phytochemicals were downloaded from PubChem. Protein structure fles (PBD ID: 4COX for COX-2 and PBD ID:5UO1for NOs) were downloaded from PDB (www.rcsb.org/pdb) and edited by removing the hetero atoms with simultaneous adding of C terminal oxygen. For docking calculations, Gasteiger Marsili partial charges were assigned to the ligands, non-polar hydrogen atoms were merged and all torsions were allowed to rotate during docking. Active pockets were identifed and ligplot of PDB. Computed atlas of surface topography of proteins server was used to cross-check the active pockets on the target protein molecules. Te Lamarckian genetic algorithm was applied for energy minimization using default parameters. Te docking results were visualized by Discovery Studio. RESULTS In the present study, docking was carried out on active sites of two target proteins 4COX and 5UO1 with β-sitosterol, isomeldenin and nimbandiol. Docking interactions of these targets with β-sitosterol, isomeldenin an dnimbandiol are presented in Figure 1-2 and Table 1-2. Te results of docking analysis of COX-2 and NOs enzyme are listed in Table 1 and 2. Afer docking the ligand protein complex was saved in pdb format then subjected for analysis in the Accelrys Discovery Studio Visualizer. Docking studies showed that β-sitosterol as well as Isomeldenin has best docking scores for COX-2 and NOs. Interaction between the neem constituents with the COX-2 and NOs are represented in Figure 1 and 2. DISCUSSION Advances in computational techniques have helped bio information to screen potential drug molecules. Te process of virtual screening has created a positive impact on the discovery and development of new drug. Te process of virtual screening uses docking and scoring of each compound from a dataset. Tis technique based on prediction of binding