COMPARISON OF ANTIOXIDANT ACTIVITIES OF DIFFERENT COMMERCIAL VARIETIES OF TEA BY USING DPPH METHOD

Abstract

Determination of radical scavenging activity and the total content of antioxidants in foods, beverages, dietary supplements and herbal extracts have been in wide demand. This relates to the fact that antioxidants can prevent free radicals, primarily highly reactive oxygen and nitrogen species from damaging human health. Antioxidant activity of different types of teas i.e. Kashmiri Chaye, Pishawri Qehwa, Black tea and Lemon grass was determined in present study. For this purpose, ethanolic extracts of tea samples were prepared and free radical, 2, 2-Diphenyl-1picrylhydrazyl (DPPH) which is widely used to test the ability of compounds to act as free radical scavengers was used. The free radical DPPH with an odd electron gives a maximum absorption at 517 nm. DPPH radical scavenging activity was observed by using different dilutions of the ethanolic extracts and taking ascorbic acid as a standard. Results showed the antioxidant activity of tea samples in order i.e. Lemon grass > Kashmiri chaye > Pishawri qehwa > Black tea. Different phytochemicals tests were also performed to determine the presence of various bioactive compounds i.e. Phenols and Tannins, Flavonoids, Carbohydrates, Saponins, Glycosides, Steroids and Terpenoids. Results showed that Flavonoids were present in high amount in all four varieties of tea studied. Phenols and Tannins were present in Kashmiri chaye and Pishawri qehwa but were lacking in lemon grass and black tea. Saponins were present only in Black tea and absent in other three varieties studied while Carbohydrates and Terpenoids were lacking in all the varieties, Glycosides were observed in all the four tea varieties studied. Presence of Steroids was observed in all varieties but the results were way more prominent for the lemon grass than other three varieties. It is being concluded from the results that lemon grass contains quite good amount of antioxidant than other types of tea studied. Phytochemicals analysis and data gathered about antioxidant content of these different tea samples can be used to estimate quality of tea.