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Determination of theanine, GABA, and other amino acids in green, oolong, black, and Pu-erh teas with dabsylation and high-performance liquid chromatography.
J Agric Food Chem. 2008 Sep 10; 56(17):7637-43.JA

Abstract

Dabsyl chloride (dimethylaminoazobenzene sulfonyl chloride), a useful chromophoric labeling reagent for amino acids and amines, was developed in this laboratory in 1975. Although several methods have been developed to determine various types of amino acids, a quick and easy method of determining theanine, GABA, and other amino acids has not been developed in one HPLC system. In this paper are analyzed the free amino acid contents of theanine and GABA in different teas (green tea, black tea, oolong tea, Pu-erh tea, and GABA tea) with a dabsylation and reverse phase high-performance liquid chromatography (HPLC) system coupled with a detector at 425 nm absorbance. Two reverse phase columns, Hypersil GOLD and Zorbax ODS, were used and gave different resolutions of dabsyl amino acids in the gradient elution program. The data suggest that the tea source or the steps of tea-making may contribute to the theanine contents variations. High theanine contents of high-mountain tea were observed in both green tea and oolong tea. Furthermore, the raw (natural fermented) Pu-erh tea contained more theanine than ripe (wet fermented) Pu-erh tea, and the GABA contents in normal teas were generally lower than that in GABA tea.

Authors+Show Affiliations

Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18652476

Citation

Syu, Kai-Yang, et al. "Determination of Theanine, GABA, and Other Amino Acids in Green, Oolong, Black, and Pu-erh Teas With Dabsylation and High-performance Liquid Chromatography." Journal of Agricultural and Food Chemistry, vol. 56, no. 17, 2008, pp. 7637-43.
Syu KY, Lin CL, Huang HC, et al. Determination of theanine, GABA, and other amino acids in green, oolong, black, and Pu-erh teas with dabsylation and high-performance liquid chromatography. J Agric Food Chem. 2008;56(17):7637-43.
Syu, K. Y., Lin, C. L., Huang, H. C., & Lin, J. K. (2008). Determination of theanine, GABA, and other amino acids in green, oolong, black, and Pu-erh teas with dabsylation and high-performance liquid chromatography. Journal of Agricultural and Food Chemistry, 56(17), 7637-43. https://doi.org/10.1021/jf801795m
Syu KY, et al. Determination of Theanine, GABA, and Other Amino Acids in Green, Oolong, Black, and Pu-erh Teas With Dabsylation and High-performance Liquid Chromatography. J Agric Food Chem. 2008 Sep 10;56(17):7637-43. PubMed PMID: 18652476.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Determination of theanine, GABA, and other amino acids in green, oolong, black, and Pu-erh teas with dabsylation and high-performance liquid chromatography. AU - Syu,Kai-Yang, AU - Lin,Chih-Li, AU - Huang,Hsiu-Chen, AU - Lin,Jen-Kun, Y1 - 2008/07/25/ PY - 2008/7/26/pubmed PY - 2008/11/1/medline PY - 2008/7/26/entrez SP - 7637 EP - 43 JF - Journal of agricultural and food chemistry JO - J Agric Food Chem VL - 56 IS - 17 N2 - Dabsyl chloride (dimethylaminoazobenzene sulfonyl chloride), a useful chromophoric labeling reagent for amino acids and amines, was developed in this laboratory in 1975. Although several methods have been developed to determine various types of amino acids, a quick and easy method of determining theanine, GABA, and other amino acids has not been developed in one HPLC system. In this paper are analyzed the free amino acid contents of theanine and GABA in different teas (green tea, black tea, oolong tea, Pu-erh tea, and GABA tea) with a dabsylation and reverse phase high-performance liquid chromatography (HPLC) system coupled with a detector at 425 nm absorbance. Two reverse phase columns, Hypersil GOLD and Zorbax ODS, were used and gave different resolutions of dabsyl amino acids in the gradient elution program. The data suggest that the tea source or the steps of tea-making may contribute to the theanine contents variations. High theanine contents of high-mountain tea were observed in both green tea and oolong tea. Furthermore, the raw (natural fermented) Pu-erh tea contained more theanine than ripe (wet fermented) Pu-erh tea, and the GABA contents in normal teas were generally lower than that in GABA tea. SN - 1520-5118 UR - https://www.unboundmedicine.com/medline/citation/18652476/Determination_of_theanine_GABA_and_other_amino_acids_in_green_oolong_black_and_Pu_erh_teas_with_dabsylation_and_high_performance_liquid_chromatography_ L2 - https://doi.org/10.1021/jf801795m DB - PRIME DP - Unbound Medicine ER -