Investigation of Organic Constituents of Commercial Tea Brands and Fresh Tea Leaves by High-Performance Liquid Chromatography

To date, the organic constituents such as caffeine, pyrogallol, gallic acid, and polyphenols (catechin and epicatechin) of the various tea brands and fresh tea leaves commercially available in Pakistan have not been investigated or published elsewhere. Therefore, the current study was undertaken to investigate the contents of these important organic constituents of the tea samples. A simple, fast and reliable isocratic reverse-phase high-performance liquid chromatographic method with slight modifications was applied for the determination of selected ingredients. The results show high level of caffeine and gallic acid in black teas compared to green teas and fresh tea leaves. Similarly, in green teas, enormous quantity of pyrogallol, catechin and epicatechin was found. Epicatechin was detected only in green teas and fresh tea leaves. Fresh tea leaves contain all the selected components but at lower concentrations compared to other tea samples. It is speculated that the remarkable increase and decrease in the concentration of the selected analytes is due to thefermentation processes used for manufacturing black and green teas and the elevated levels can be controlled using the optimal fermentation and manufacturing conditions.