Comparative study of the antioxidant activity of popular tea brands from trade market

Tea is a traditional drink containing antioxidants of phenolic nature and other phytonutrients. 17 kinds of tea in bags were analysed. Extraction of phenolic substances and flavonoids was carried out with 50% ethanol, after which the content of phenolic substances, flavonoids, antiradical activity by the DPPH method, restoring ability by the FRAP method were determined. The obtained results testify the high potential of certain types of tea to block free radicals in model experiments in vitro due to the presence of phenolic substances (1086–1277 mg of gallic acid / 100 g of raw material). The most anti-radical activity among the studied objects belongs to GreenField teas – 0.33 and 0.34 mg / ml (the concentration of extract required to bind 50% of the DPPH radicals in the solution is 1 mg / ml). The ability to express a reducing ability for iron ions significantly distinguishes Black Curtis and Black Blooming Thyme (21.96 and 19.44 mmol Fe2+ / 1 kg of raw material). Study of antioxidant activity in vitro of the presented objects revealed a group of objects containing phenolic substances, flavonoids, which in the model experiments in vitro possess high anti-radical, antioxidant and reducing properties.