FINLAY GREEN TEA POSSESSES THE HIGHEST IN VITRO ANTIOXIDANT ACTIVITY AMONG THE 20 COMMERCIALLY AVAILABLE TEA BRANDS OF 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.