DETECTION OF MEDICINALLY IMPORTANT PLANT METABOLITES IN GREEN TEA

Michael C. Tims and Lane Sander

 

Green tea (Camellia sinensis) is a popular beverage that has been reported to contain compounds with anticancer and antimicrobial activities, as well as those providing cardiovascular protection. The predominant compounds are polyphenols, of which the major class found in green tea leaves are monomeric flavanols called catechins. The concentration of total catechins in green tea leaves is approximately 30%. The trans-flavan 3 β-ols isomers include catechin, catechin gallate, gallocatechin, gallocatechin gallate; and the cis-flavan 3 α-ols isomers include epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. Methyl xanthines are a second major class of compounds. Caffeine concentration is approximately 3% and the caffeine precursors, alkaloids theophylline and theobromine, may also be present in green tea. Theanine (5-N-ethylglutamine) is the major amino acid (3% dry weight) found in green tea as D- and L- isomers, of which the D- form predominates. Research indicates that theanine improves flavor and may play a role in preventing neuronal death, lowering blood pressure and counteracting the stimulus associated with green tea caffeine content. Accurate measurement and detection of these compounds is necessary for conducting clinical trials, assuring good manufacturing practices and researching how ecological influences alter the composition of the medicinally relevant compounds. A HPLC-UV analytical method has been developed that for the first time is able to detect and measure the concentration of all twelve metabolites.

 

Author information:

Michael C. Tims

Mentor: Lane Sander

Analytical Chemistry Division

Bldg 227 room A119

MS 8392        

x 4026 (ph)

x 0685 (fax)

michael.tims@nist.gov

not a member of Sigma Xi

 

Poster Category:  Chemistry