Total polyphenol, antioxidant and antibacterial activities of black mate tea

Abstract

Black mate tea was extracted with different 50% solvents (acetone, N,N-dimethyl formamide (DMF), ethanol and methanol) for 2, 8 and 18 h. The extracts were screened for polyphenol content, antioxidant and antibacterial activities. Total polyphenol content of the extracts ranged from 97.01 to 119.28 mg gallic acid equivalent (GAE)/g dry weight (dw) tea depending on the solvent used and extraction time applied. In general, methanol was the least efficient solvent for polyphenol extraction from black mate tea and the efficiency of the others was found to be similar. AU extracts showed antioxidant activity by 2,2-diphenyl-1-picryhydrazyl (DPPH) radical and reducing power. Different trend was observed for each method with respect to solvents used. The extracts possessed antibacterial activity depending on the solvent used and bacterium tested and the results sowed that black mate tea extracts had strong antimicrobial activity against selected bacteria, except for E. coli 0157: H7. While S. aureus was found to be the most sensitive to all extracts, E. coli was the most resistant among bacteria tested.