Determination and Comparison of γ-Aminobutyric Acid (GABA) Content in Pu-erh and Other Types of Chinese Tea
"Two previous studies have reported that pu-erh tea contains a high level of γ-aminobutyric acid (GABA), which is the major inhibitory neurotransmitter in the central nervous system and has several physiological functions. However, two other researchers have demonstrated that the GABA content of several pu-erh teas was low. Due to the high value and health benefits of GABA, analysis of mass-produced pu-erh tea is necessary to determine whether it is actually enriched with GABA. A high-performance liquid chromatography (HPLC) method was developed for the determination of GABA in tea, the results of which were verified by amino acid analysis using an Amino Acid Analyzer (AAA). A total of 114 samples of various types of Chinese tea, including 62 pu-erh teas, 13 green teas, 8 oolong teas, 8 black teas, 3 white teas, 4 GABA teas, and 16 process samples from two industrial fermentations of pu-erh tea (including the raw material and the first to seventh turnings), were analyzed using HPLC. Statistical analysis demonstrated that the GABA content in pu-erh tea was significantly lower than that in other types of tea (p < 0.05) and that the GABA content decreased during industrial fermentation of pu-erh tea (p < 0.05). This mass analysis and comparison suggested GABA was not a major bioactive constituent and resolved the disagreement GABA content in pu-erh tea. In addition, the GABA content in white tea was found to be significantly higher than that in the other types of tea (p < 0.05), leading to the possibility of producing GABA-enriched white tea."
"In conclusion, we found that Pu-Erh tea leaves had abundant content of GABA as bioactive components. The metabolites of GABA are also potent antioxidants and anti-inflammatory agents. This suggests that natural antioxidants play an important role in neuroprotection under excitotoxins and GABA in the Pu-Erh tea was responsible for this protection. Pu-Erh leaf extract and GABA ameliorates oxidative stress in KA-induced status epilepticus. The molecular mechanisms of PETL extract and GABA on SE-induced excitotoxicity warrants further study for their therapeutic potential."
http://jbiomedsci.biomedcentral.com/articles/10.1186/1423-0127-18-75
http://pubs.acs.org/doi/abs/10.1021/jf104601v
"Two previous studies have reported that pu-erh tea contains a high level of γ-aminobutyric acid (GABA), which is the major inhibitory neurotransmitter in the central nervous system and has several physiological functions. However, two other researchers have demonstrated that the GABA content of several pu-erh teas was low. Due to the high value and health benefits of GABA, analysis of mass-produced pu-erh tea is necessary to determine whether it is actually enriched with GABA. A high-performance liquid chromatography (HPLC) method was developed for the determination of GABA in tea, the results of which were verified by amino acid analysis using an Amino Acid Analyzer (AAA). A total of 114 samples of various types of Chinese tea, including 62 pu-erh teas, 13 green teas, 8 oolong teas, 8 black teas, 3 white teas, 4 GABA teas, and 16 process samples from two industrial fermentations of pu-erh tea (including the raw material and the first to seventh turnings), were analyzed using HPLC. Statistical analysis demonstrated that the GABA content in pu-erh tea was significantly lower than that in other types of tea (p < 0.05) and that the GABA content decreased during industrial fermentation of pu-erh tea (p < 0.05). This mass analysis and comparison suggested GABA was not a major bioactive constituent and resolved the disagreement GABA content in pu-erh tea. In addition, the GABA content in white tea was found to be significantly higher than that in the other types of tea (p < 0.05), leading to the possibility of producing GABA-enriched white tea."
"In conclusion, we found that Pu-Erh tea leaves had abundant content of GABA as bioactive components. The metabolites of GABA are also potent antioxidants and anti-inflammatory agents. This suggests that natural antioxidants play an important role in neuroprotection under excitotoxins and GABA in the Pu-Erh tea was responsible for this protection. Pu-Erh leaf extract and GABA ameliorates oxidative stress in KA-induced status epilepticus. The molecular mechanisms of PETL extract and GABA on SE-induced excitotoxicity warrants further study for their therapeutic potential."
http://jbiomedsci.biomedcentral.com/articles/10.1186/1423-0127-18-75
http://pubs.acs.org/doi/abs/10.1021/jf104601v