Malaysian Journal of Pharmaceutical Sciences Vol. 11, No. 2, 11–20 (2013) © Penerbit Universiti Sains Malaysia, 2013 FINLAY GREEN TEA POSSESSES THE HIGHEST IN VITRO ANTIOXIDANT ACTIVITY AMONG THE 20 COMMERCIALLY AVAILABLE TEA BRANDS OF BANGLADESH ALAK KANTI DUTTA 1 , MUHAMMAD ALI SIDDIQUEE 2 , SHAHDAT HOSSAIN 3 AND YEARUL KABIR 1* 1 Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka-1000, Bangladesh 2 Grain Quality and Nutrition Division, Bangladesh Rice Research Institute, Gazipur-1701, Dhaka, Bangladesh 3 Department of Biochemistry and Molecular Biology, Jahangirnagar University, Savar-1342, Dhaka, Bangladesh In vitro antioxidant activities of water extract of 20 brands of tea of Bangladesh were assessed in the present investigation. Antioxidant activities were determined by estimating total antioxidant capacity (TAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and ferrous ion chelating (FIC) ability. Finlay Green Tea had the highest polyphenol content [103.0±0.3 mg gallic acid equivalent (GAE)/g], concurrently with the highest DPPH-radical scavenging activity (IC50) (19.0±3.0 g/mL), FRAP (97.0±1.4 mg GAE/g) and TAC (325.0±0.6 mg GAE/g) but moderate FIC ability [1.22±0.09 mg disodium ethylenediaminetetracetate (EDTA)/g]. The level of antioxidant activity, without FIC ability, was strongly associated with the total phenolic content (TPC). Therefore, the teas of Bangladesh, especially the green tea (Camellia sinensis L.), may serve as a potential dietary source of natural phenolic antioxidants. Keywords: Antioxidant property, Tea, Natural phenolic antioxidants, Polyphenols INTRODUCTION Tea is the most commonly drunk beverage on earth and is being consumed socially and habitually by people since 3000 BC. Tea (Camellia sinensis L.), a cultivated evergreen plant, is native to China, later spread to India and Japan, then to Europe and Russia, arriving in the New World in the late 17th century (Sharangi 2009). Antioxidants are capable of stabilising or deactivating reactive oxygen species (ROS) such as hydroxyl radical, ferryl ion, superoxide radical anion, peroxyl radical and hydrogen peroxide, which are induced by oxidative stress, before they later attack cells and biological targets. Antioxidants are therefore believed to be crucial for maintaining optimal cellular and systemic health and well-being (Rahman 2007; Dufresne and Farnworth 2001). During the last decade, the effects of tea and tea polyphenols were extensively investigated and studies showed that tea is capable of lowering the risk of cardiovascular diseases and cancers (Chen et al. 2008; Mukamal et al. 2007), reducing body fat, systolic blood pressure (SBP), and low density lipoprotein (LDL) cholesterol (Nagao, Hase and Tokimitsu 2007). Among age-associated pathologies and neurodegenerative diseases, green tea was shown to confer significant * Corresponding author: Yearul Kabir, email: ykabir@yahoo.com