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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Main Authors: Keiko Unno, Takashi Ikka, Hiroto Yamashita, Yoko Kameoka, Yoriyuki Nakamura
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/1/103
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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
collection DOAJ
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.
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issn 2304-8158
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publishDate 2025-01-01
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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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