ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org An International Open Free Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2017, Vol. 33, No.(6): Pg. 38-44 Allylxanthone Derivatives as Xanthine Oxidase Inhibitors: Synthesis, Biological Evaluation and Molecular Docking Study THONGCHAI KHAMMEE 1 *, WARAKORN JONGSU 1 , MAYUSO KUNO 2 and SUNIT SUKSAMRARN 2 1 Department of Chemistry, Faculty of Science and Technology, Phranakhon Rajabhat University, Bangkok, 10220, Thailand. 2 Department of Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok, 10110, Thailand. *Corresponding author E-mail: thongchai.k@pnru.ac.th http://dx.doi.org/10.13005/ojc/340104 (Received: November 17, 2017; Accepted: December 01, 2017) ABSTRACT Gout is one of the most severe health problems of the aged and is caused by high levels of uric acid in the blood. The inhibition of Xanthine oxidase (XO) is one strategy to retain gout disease. Oxygenated xanthones and derivatives have been shown many important biological activities. However, some xanthones have the small amount of nature and its sulfur analogs, thioxanthone has not been well studied in their bioactivity. A series of hydroxyxanthones and allylxanthones analogous 3-5 have been synthesized and screened for their anti-XO activity. Leads to the discovery of 2,4-diallyl-1,3-dihydroxythioxanthone (5b) as the most active inhibitor with IC 50 = 0.69±0.02 mM. Consequent molecular docking analysis by AutoDock 4.2 indicated that the most active compound (5b) inhibits XO by accommodated at the binding site of Xanthine oxidase. Keywords: Xanthine oxidase inhibitors, xanthone, thioxanthone, molecular docking. INTRODUCTION Xanthine oxidase (XO) is a vital enzyme that catalyzes the oxidation of hypoxanthine to xanthine and the oxidation of xanthine to uric acid in the purine pathway and plays a significant role in hyperuricemia and gout 1 . There are two conventional treatments for gout that are used anti- inflammatory agents to relieve the symptoms of the disease and XO inhibitors. XO inhibitors are utilized to treat gout by blocked the synthesis of uric acid. Among of XO inhibitors, allopurinol is a standard drug to treat gout and acts as XO inhibitor. The use of allopurinol is restricted by adverse side effects including hypersensitivity reaction, renal toxicity 2 , Steven-Johnson syndrome and epidermal This is an Open Access article licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-nc-sa/4.0/ ), which permits unrestricted NonCommercial use, distribution and reproduction in any medium, provided the original work is properly cited.