HPTLC Methods for Identification of Green Tea and Green Tea Extract

Abstract

For centuries, the leaves of Camellia sinensis have been used to make green, black, and special types of tea; it has been the basis for one of the most popular beverages all over the world. More recently, green tea has become the raw material for extracts which are used in various beverages, health foods, dietary supplements, and cosmetic items. In view of the Good Manufacturing Practice (cGMP) for dietary supplements, mandating proper identification of raw materials and finished products, it is very important to have the necessary analytical tools at hand.

This paper presents HPTLC methods for identification of green tea and green tea extract. On silica gel 60 with ethyl formate, toluene, formic acid, water (30:1.5:4:3) as mobile phase, the flavonoid fingerprint of green tea can give information about the geographical origin of the material. The mobile phase toluene, acetone, formic acid (9:9:2) allows the discrimination of green tea from black and other specialty teas, based on the polyphenol pattern. The latter method has been validated, addressing specificity, stability, reproducibility, and robustness. For additional quality control of extracts, ethyl acetate, methanol, and water (20:2.7:2) can be used as mobile phase to investigate the alkaloid profile, whereas, 1‐butanol, acetone, acetic acid, water (7:7:2:4) provides an amino acid profile.

Keywords:

• Camellia sinensis
• Fingerprint
• Flavonoids
• Green tea
• Polyphenols
• Validation

Acknowledgment

The authors would like to thank The London Tea Company (Münchenstein, Switzerland) for their generous support.