Antioxidant Activity and Phytochemical Screening of Different Varieties of Tea

Abstract

Tea is consumed by a range of age groups in all levels of society. Tea is one of the richest sources of antioxidants and the three major forms of antioxidant tea are green tea, oolong tea and black tea. White tea is one of the newer entries. Antioxidant activity of tea is affected by many natural polyphenols: catechins, oxyaromatic acids, tannins, flavonols, thearubigins, theaflavins, etc. The present study was conducted to determine total antioxidant activity of different teas, black, white, green and oolong tea, to determine flavonoid content, total phenol content and study phytochemical screening of the different teas. A survey was conducted among 40 subjects to assess the popularity of tea consumption, awareness on the different varieties of tea, its health benefits, type and brand preferred etc. Among the four samples of tea, antioxidant activity was tested by using DPPH method. The methanolic extracts of white tea showed highest antioxidant activity, with IC₅₀ value of 231.52 μg/ml. Black tea showed weak antioxidant activity with IC₅₀ value of 317.45 μg/ml. The antioxidant activity of white tea was higher than the other varieties of teas. Flavonoid content is higher in white tea than in green, oolong and black tea. Phenol and tannin content was also high in white tea than other three teas. Hence antioxidant activity, free radical scavenging and microbial activity were higher in white tea than the other varieties. From the sensory evaluation conducted, white tea was found to be highly acceptable.