INTRODUCTION Epigallocatechin-3-gallate (EGCG) is the main constituent of green tea extract 1 which is antioxidant, antiinflammatory and antiatherogenicproperties 2 . However, some studies showed that EGCG and other catechins were unstable under high tem- perature and neutral or alkaline conditions (pH > 6) 3,4 . There- fore, the stability of EGCG is dependent on pH. Absorption of EGCG takes place in the small intestine where the pH lies between 7-8, hence, substantial quantities of the unabsorbed and partially degraded EGCG pass from the small to the large intestine where it undergoes further degradation by the action of local microbiota 2 . Hence, if EGCG is provided in the alkaline resistant form, its biovailability might be increased. The chitosan is a straight-chain copolymer composed of D-glucosamine and N-acetyl-D-glucosamine being obtained by the partial deacetylation of chitin. Chitosan is the most abundant basic biopolymer and is structurally similar to cellulose, which is a homopolysaccharide of glucose. Chitosan is considered one of the most valuable polymer for biomedical and pharmaceutical applications due to its biodegradability, biocompatibility, antimicrobial, non-toxicity, adsorption properties etc. 5 . Chitosan is insoluble in distilled water, but Synthesis and Characterization of Major Green Tea Catechin Nanoparticle† S. ASHOK KUMAR * , M. SURESH, S.N. KISHORE KUMAR and P. KALAISELVI Department of Medical Biochemistry, Dr. ALM PGIBMS, University of Madras, Taramani, Chennai-600 113, India *Corresponding author: Fax: +91 44 24540709; Tel: +91 44 24547085; E-mail: pkalaiselvi@yahoo.com; ashunom5996@gmail.com AJC-12871 Epigallocatechin-3-gallate (EGCG), a principal polyphenol, which is most abundant and active component in green tea which has wide therapeutic effects against various diseases. However, EGCG used in clinical application has some downsides due to its low bioavailability and half-life. Hence increasing the bioavailability of EGCG without losing its potential therapeutic effects is of great challenge. In this study, we have prepared EGCG-loaded chitosan nanoparticles by ionic gelation method using sodium tripolyphosphate as ionic cross linking agent. The size, surface morphology, drug entrapment efficiency, drug releasing property and free radical scavenging activity of EGCG nanoparticle has been studied. The size of nanoparticle as determined by SEM ranged from 88-399 nm. FTIR results confirmed the drug entrapment in nanoparticles. The antioxidant property of nano-particulated EGCG and drug releasing assay showed sustained release of EGCG in the acid medium, which helps in increasing bioavailability of drug. Moreover the antioxidant activity of the drug was not found to be hindered by conversion into nanoparticles. However, further in vivo studies are warranted to explicate its therapeutic efficacy. Key Words: Epigallocatechin-3-gallate, Nanoparticle, Chitosan, FTIR, SEM. †International Conference on Nanoscience & Nanotechnology, (ICONN 2013), 18-20 March 2013, SRM University, Kattankulathur, Chennai, India soluble in diluted acetic acid solution. Hence, chitosan was selected for the preparation of EGCG nanoparticles. Recently, a new approach for the preparation of nanoparticles made solely of hydrophilic polymer has been described by Majeti and Kumar 5 . The preparation technique, based on an ionic gelation process, is extremely mild and involves a mixture of two aqueous phases at room temperature. One phase contains chitosan (CS) and the other contains sodium tripolyphosphate. Most of nanoparticles synthesis from water-insoluble polymers involves either heat, organic solvent or high shear force that can be harmful to the drug stability. Moreover, some preparation methods such as emulsion poly- merization and solvent evaporation are complex and require a number of preparation steps that are more time and energy consuming. In contrast, water-soluble polymers offer mild and simple preparation methods without the use of organic solvent and high shear force. Therefore chitosan is a best choice for making drug loaded nanoparticle 6 . In order to fully maximize the therapeutic utility of EGCG, there is a need to enhance its oral absorption. The idea that nanoparticles might protect labile drugs from enzymatic degradation in the gastrointestinal tract (GIT) leads to the development of nanoparticles as oral delivery systems. Mecha- Asian Journal of Chemistry; Vol. 25, Supplementary Issue (2013), S343-S346