茶多酚

綠茶中嘅大多數多酚係黃烷-3-醇（兒茶素）。

茶多酚係統稱由茶中發現到嘅啲天然植物化合物多酚類。啲化合物會影響茶嘅味道同口感。茶多酚包括兒茶素、茶黃素、單寧同埋類黃酮。

綠茶發現嘅多酚包括埋表沒食子兒茶素沒食子酸酯（EGCG）、表沒食子兒茶素、表兒茶素沒食子酸酯同埋表兒茶素之類成分；綠茶裏便仲含有啲黃烷醇似山柰酚，槲皮素同楊梅黃酮。[1]

兒茶素類

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綠茶UV 280 nm色譜圖。最高峰係咖啡因，第二高峰係EGCG

兒茶素類包括表沒食子兒茶素-3-沒食子酸酯（EGCG）、表兒茶素（EC）、表兒茶素-3-沒食子酸酯（ECg）、表沒食子兒茶素（EGC）、兒茶素、同埋沒食子兒茶素（GC）。綠茶中EGCG嘅含量高啲。[2]

啲兒茶素佔到25％嘅新鮮茶葉乾重[3]， 之兒茶素嘅總含量出於物種差異、克隆變異（clonal variation）、生長位置、季節、光照變化同海拔高度嘅唔同而走差好大。佢哋幾乎存在於由山茶製成嘅所有茶中，包括埋白茶、綠茶、紅茶同埋烏龍茶。

歐洲食品安全局（European Food Safety Authority）喺2011年進行有嘅一項分析發現，茶中啲兒茶素戥維持正常血液LDL-膽固醇濃度之間冇顯示到因果關係。[4]

4-羥基苯甲酸，3,4-二羥基苯甲酸（原兒茶酸），3-甲氧基-4-羥基苯丙酸同3-甲氧基-4-羥基苯甲酸（香草酸）係綠茶浸液（infusion）落到人體入邊主要嘅兒茶素代謝產物。[5]

茶黃素

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大吉嶺紅茶浸液：由於茶黃素含量高啲，精製紅茶有比起紅色嚟似橙色多啲嘅色調。

睇在茶葉嘅氧化度，兒茶素單體結構捱代謝成二聚體茶黃素戥低聚物茶紅素。[6]紅茶啲苦澀味歸功於茶黃素。一杯紅茶（200毫升）裏便啲茶黃素嘅平均含量係12.18 毫克。

紅茶裏便發現到三種主要類型嘅茶黃素，即茶黃素（TF-1），茶黃素-3-沒食子酸酯（TF-2）戥茶黃素-3,3-二沒食子酸酯（TF-3）。[7]

單寧

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單寧酸係一種澀味、苦味嘅多酚化合物，可以結合同埋整沉澱啲有機化合物去。沒食子酸參與結合成嘅所有兒茶素，例如EGCG（表沒食子兒茶素沒食子酸酯），之係具有收斂特性嘅單寧。[8]

類黃酮

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截至2020年，啲喊做類黃酮嘅酚類仲畀初步研究緊，之冇證據表明類黃酮會對身體健康或疾病風險有影響。[9][10]茶係普通食品同飲料產品裏便類黃酮含量最高嘅一種。 兒茶素類係生長中嘅茶葉中最大嘅類黃酮類。[6]根據美國農業部發布嘅報告，喺200毫升嘅茶入便，類黃酮嘅平均總含量綠茶係266.68毫克、紅茶係233.12 毫克。

研究

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2020年嘅一項審查發現，低至中等質素嘅證據表明每日飲茶可能會降低心血管疾病同死亡嘅風險。[11]

2007年嘅一項研究發現，營養混合物含有綠茶（多酚）同維他命C嘅會「抑制感染細胞中病毒核蛋白嘅產生」。即係話，份研究發現，含綠茶嘅營養混合物都係一種抗病毒藥物，之冇毒副作用。[12]

考

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  1. ↑ Khan N, Mukhtar H (2013). "Tea and health: studies in humans". Current Pharmaceutical Design (Literature Review). 19 (34): 6141–7. doi:10.2174/1381612811319340008. PMC 4055352. PMID 23448443.
  2. ↑ Thermo Scientific (Dionex) Application Note 275. Sensitive Determination of Catechins in Tea by HPLC . Retrieved 3 August 2013.
  3. ↑ Balentine DA, Harbowy ME, Graham HN (1998). "Tea: the Plant and its Manufacture; Chemistry and Consumption of the Beverage". 出自 Spiller GA (編). Caffeine. Boca Raton: CRC Press. p. 35. ISBN 978-0-8493-2647-9.
  4. ↑ EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies) (2011). "Scientific Opinion on the substantiation of health claims related to Camellia sinensis (L.) Kuntze (tea), including catechins in green tea, and improvement of endothelium-dependent vasodilation (ID 1106, 1310), maintenance of normal blood pressure". EFSA Journal. 9 (4): 2055. doi:10.2903/j.efsa.2011.2055.
  5. ↑ Pietta, P. G.; Simonetti, P.; Gardana, C.; Brusamolino, A.; Morazzoni, P.; Bombardelli, E. (1998). "Catechin metabolites after intake of green tea infusions". BioFactors. 8 (1–2): 111–8. doi:10.1002/biof.5520080119. PMID 9699018.
  6. ↑ 6.0 6.1 Peterson, J.; Dwyer, J.; Bhagwat, S.; Haytowitz, D.; Holden, J.; Eldridge, A.L.; Beecher, G.; Aladesanmi, J. (2005). "Major flavonoids in dry tea". Journal of Food Composition and Analysis. 18 (6): 487–501. doi:10.1016/j.jfca.2004.05.006.
  7. ↑ Del Rio, Daniele; Stewart, Amanda J.; Mullen, William; Burns, Jennifer; Lean, Michael E. J.; Brighenti, Furio; Crozier, Alan (2004). "HPLC-MSnAnalysis of Phenolic Compounds and Purine Alkaloids in Green and Black Tea". Journal of Agricultural and Food Chemistry. 52 (10): 2807–15. doi:10.1021/jf0354848. PMID 15137818.
  8. ↑ Crozier, Alan; Jaganath, Indu B.; Clifford, Michael N. (2009). "Dietary phenolics: Chemistry, bioavailability and effects on health". Natural Product Reports. 26 (8): 1001–43. CiteSeerX 10.1.1.608.4407. doi:10.1039/b802662a. PMID 19636448.
  9. ↑ "Flavonoids" (英文). Linus Pauling Institute, Oregon State University, Corvallis. 2016. 喺2020-04-15搵到.
  10. ↑ EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA)2, 3 European Food Safety Authority (EFSA), Parma, Italy (2010). "Scientific Opinion on the substantiation of health claims related to various food(s)/food constituent(s) and protection of cells from premature aging, antioxidant activity, antioxidant content and antioxidant properties, and protection of DNA, proteins and lipids from oxidative damage pursuant to Article 13(1) of Regulation (EC) No 1924/20061". EFSA Journal. 8 (2): 1489. doi:10.2903/j.efsa.2010.1489.{{cite journal}}: CS1 maint: multiple names: 作者名單 (link)
  11. ↑ Chung, Mei; Zhao, Naisi; Wang, Deena; Shams-White, Marissa; Karlsen, Micaela; Cassidy, Aedín; Ferruzzi, Mario; Jacques, Paul F.; Johnson, Elizabeth J.; Wallace, Taylor C. (19 February 2020). "Dose–Response Relation between Tea Consumption and Risk of Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis of Population-Based Studies". Advances in Nutrition (英文). doi:10.1093/advances/nmaa010. PMID 32073596.
  12. ↑ https://www.drrathresearch.org/attachments/Infectious%20Diseases/173_biofactors_2007_31-1.pdf