Determination of Theanine and Catechin in Camellia sinensis (Kangra Tea) Leaves by HPTLC and NMR Techniques

Abstract

Camellia sinensis is used to make special tea and also become a raw material for dietary supplements, health foods, and cosmeceuticals. Theanine (amino acid) and catechins (polyphenol) are most abundantly found in tea leaves. Theanine and catechins are also responsible for taste and flavor of tea products along with therapeutic and nutritional values. Hence, identification and quantification method for theanine and catechin has been developed using high performance thin layer chromatography (HPTLC) and NMR techniques. HPTLC method was validated for selectivity, sensitivity, accuracy, and precision. Theanine and catechin were quantified in three tea samples including randomly plucked tea leaves (HAR), authentically plucked tea leaves (HAN), and processed tea (HAT). Both theanine and catechin were found maximum in HAN as compared to HAR and HAT. The Validated HPTLC method is economical, rapid, and highly suitable for quantification of theanine and catechin. Moreover NMR studies were also used for the qualitative and quantitative estimation of theanine and catechin along with other important metabolites in C. sinensis samples.