Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator
The major components of tea leaves and their infusions were analyzed for various types of green tea available in Japan in 2022. Almost all the green teas used were from the first crop, known for their high amino acid content. The amino acids theanine and arginine in green tea have been shown to redu...
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MDPI AG
2025-01-01
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| Series: | Foods |
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| author | Keiko Unno Takashi Ikka Hiroto Yamashita Yoko Kameoka Yoriyuki Nakamura |
| author_facet | Keiko Unno Takashi Ikka Hiroto Yamashita Yoko Kameoka Yoriyuki Nakamura |
| author_sort | Keiko Unno |
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| description | The major components of tea leaves and their infusions were analyzed for various types of green tea available in Japan in 2022. Almost all the green teas used were from the first crop, known for their high amino acid content. The amino acids theanine and arginine in green tea have been shown to reduce stress. On the other hand, epigallocatechin gallate (EGCG) and caffeine, the major components of green tea, counteract the effects of theanine and arginine. We have shown that the CE/TA ratio, which is the ratio of the molar sum of caffeine (C) and EGCG (E) to the molar sum of theanine (T) and arginine (A), can be used to evaluate the stress-relieving effects of each green tea. Green tea with a CE/TA ratio smaller than 3 can be expected to have a stress-reducing effect. The CE/TA ratios of the tea leaves and infusions of Gyokuro, Sencha, and Tamaryokucha were less than 3, indicating that these teas are expected to have stress-relieving effects. In addition, when the same tea leaves were infused repeatedly, it was found that most of the amino acids were eluted by the first and second cups; therefore, no stress-relieving effect could be expected after the third cup. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2025-01-01 |
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| series | Foods |
| spelling | doaj-art-039d851db72e4d09a99c76c2de018cbe2025-01-10T13:17:48ZengMDPI AGFoods2304-81582025-01-0114110310.3390/foods14010103Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an IndicatorKeiko Unno0Takashi Ikka1Hiroto Yamashita2Yoko Kameoka3Yoriyuki Nakamura4Tea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, JapanFaculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, JapanFaculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, JapanTea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, JapanTea Science Center, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, JapanThe major components of tea leaves and their infusions were analyzed for various types of green tea available in Japan in 2022. Almost all the green teas used were from the first crop, known for their high amino acid content. The amino acids theanine and arginine in green tea have been shown to reduce stress. On the other hand, epigallocatechin gallate (EGCG) and caffeine, the major components of green tea, counteract the effects of theanine and arginine. We have shown that the CE/TA ratio, which is the ratio of the molar sum of caffeine (C) and EGCG (E) to the molar sum of theanine (T) and arginine (A), can be used to evaluate the stress-relieving effects of each green tea. Green tea with a CE/TA ratio smaller than 3 can be expected to have a stress-reducing effect. The CE/TA ratios of the tea leaves and infusions of Gyokuro, Sencha, and Tamaryokucha were less than 3, indicating that these teas are expected to have stress-relieving effects. In addition, when the same tea leaves were infused repeatedly, it was found that most of the amino acids were eluted by the first and second cups; therefore, no stress-relieving effect could be expected after the third cup.https://www.mdpi.com/2304-8158/14/1/103theanineargininecaffeineepigallocatechin gallategreen teastress reduction |
| spellingShingle | Keiko Unno Takashi Ikka Hiroto Yamashita Yoko Kameoka Yoriyuki Nakamura Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator Foods theanine arginine caffeine epigallocatechin gallate green tea stress reduction |
| title | Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator |
| title_full | Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator |
| title_fullStr | Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator |
| title_full_unstemmed | Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator |
| title_short | Stress-Relieving Effects of Japanese Green Tea: Evaluation Using the Molar Ratio of Caffeine and Epigallocatechin Gallate to Theanine and Arginine as an Indicator |
| title_sort | stress relieving effects of japanese green tea evaluation using the molar ratio of caffeine and epigallocatechin gallate to theanine and arginine as an indicator |
| topic | theanine arginine caffeine epigallocatechin gallate green tea stress reduction |
| url | https://www.mdpi.com/2304-8158/14/1/103 |
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