Comparative Studies on Green Tea and Black Tea of Various Brands Obtained From Commercial Market for its Gallic Acid Content by HPLC Technique

Abstract

Standardization of herbal drugs is the process of prescribing a set of standards or inherent characteristics, constant parameters, definitive quantitative and qualitative values that carry on assurance of quality, safety, efficacy and reproducibility. The objectives of present study is to carry out the estimation of  gallic acid which is one of the polyphenolic compound responsible for antioxidant activity from green tea and black tea by High Performance Liquid Chromatographic Techniques (HPLC) to check the content uniformity. The collected tea samples were subjected to aqueous extraction and the extract was used for HPLC analysis using gallic acid as standard. The result reveals that there are lots of variations between the samples and the percentage of gallic acid is not uniform in all the collected samples. The results clearly reveal that the gallic acid content is high in green tea compared with black tea. The highest amount of gallic acid present in the green tea sample is 0.338%w/w and from black tea is 0.187%w/w. From this study it was concluded that the better antioxidant activity of green tea may be due to the presence of high content of polyphenols.