Compendium of the most significant studies with reference to properties, intake, effects.

Effects of Tannase and Ultrasound Treatment on the Bioactive Compounds and Antioxidant Activity of Green Tea Extract.
Xu XY, Meng JM, Mao QQ, Shang A, Li BY, Zhao CN, Tang GY, Cao SY, Wei XL, Gan RY, Corke H, Li HB.
Antioxidants (Basel). 2019 Sep 1;8(9). pii: E362. doi: 10.3390/antiox8090362.

Green tea consumption and mortality in Japanese men and women: a pooled analysis of eight population-based cohort studies in Japan.
Abe SK, Saito E, Sawada N, Tsugane S, Ito H, Lin Y, Tamakoshi A, Sado J, Kitamura Y, Sugawara Y, Tsuji I, Nagata C, Sadakane A, Shimazu T, Mizoue T, Matsuo K, Naito M, Tanaka K, Inoue M; Research Group for the Development and Evaluation of Cancer Prevention Strategies in Japan.
Eur J Epidemiol. 2019 Aug 7. doi: 10.1007/s10654-019-00545-y.

Antioxidative, Anti-Inflammatory, and Anticancer Effects of Purified Flavonol Glycosides and Aglycones in Green Tea.
Rha CS, Jeong HW, Park S, Lee S, Jung YS, Kim DO.
Antioxidants (Basel). 2019 Aug 5;8(8). pii: E278. doi: 10.3390/antiox8080278.

Antibacterial activities of green tea crude extracts and synergistic effects of epigallocatechingallate (EGCG) with gentamicin against MDR pathogens.
Parvez MAK, Saha K, Rahman J, Munmun RA, Rahman MA, Dey SK, Rahman MS, Islam S, Shariare MH.
Heliyon. 2019 Jul 22;5(7):e02126. doi: 10.1016/j.heliyon.2019.e02126

Function of Green Tea Catechins in the Brain: Epigallocatechin Gallate and its Metabolites.
Pervin M, Unno K, Takagaki A, Isemura M, Nakamura Y.
Int J Mol Sci. 2019 Jul 25;20(15). pii: E3630. doi: 10.3390/ijms20153630.

The effects of green tea on lipid metabolism and its potential applications for obesity and related metabolic disorders - An existing update.
Dinh TC, Thi Phuong TN, Minh LB, Minh Thuc VT, Bac ND, Van Tien N, Pham VH, Show PL, Tao Y, Nhu Ngoc VT, Bich Ngoc NT, Jurgoński A, Thimiri Govinda Raj DB, Van Tu P, Ha VN, Czarzasta J, Chu DT.
Diabetes Metab Syndr. 2019 Mar - Apr;13(2):1667-1673. doi: 10.1016/j.dsx.2019.03.021

The effect of green tea on inflammatory mediators: A systematic review and meta-analysis of randomized clinical trials.
Haghighatdoost F, Hariri M.
Phytother Res. 2019 Sep;33(9):2274-2287. doi: 10.1002/ptr.6432.

Green tea consumption and risk of breast cancer: A systematic review and updated meta-analysis of case-control studies.
Yu S, Zhu L, Wang K, Yan Y, He J, Ren Y.
Medicine (Baltimore). 2019 Jul;98(27):e16147. doi: 10.1097/MD.0000000000016147.

Green Tea Consumption and Esophageal Cancer Risk: A Meta-analysis.
Yi Y, Liang H, Jing H, Jian Z, Guang Y, Jun Z, Zhu H, Jian L.
Nutr Cancer. 2019 Jul 5:1-9. doi: 10.1080/01635581.2019.1636101

Green tea supplementation improves oxidative stress biomarkers and modulates IL-6 circulating levels in obese women.
Noronha NY, Pinhel MAS, Nicoletti CF, Quinhoneiro DCG, Pinhanelli VC, Oliveira BAP, Cortes-Oliveira C, Delfino HBP, Wolf LS, Frantz FG, Marchini JS, Nonino CB.
Nutr Hosp. 2019 Jul 1;36(3):583-588. doi: 10.20960/nh.2159

Functional and molecular effects of a green tea constituent on oral cancer cells.
Belobrov S, Seers C, Reynolds E, Cirillo N, McCullough M.
J Oral Pathol Med. 2019 Aug;48(7):604-610. doi: 10.1111/jop.12914.

Effect of Green Tea Phytochemicals on Mood and Cognition.
Dietz C, Dekker M.
Curr Pharm Des. 2017;23(19):2876-2905. doi: 10.2174/1381612823666170105151800.

Green tea effects on cognition, mood and human brain function: A systematic review.
Mancini E, Beglinger C, Drewe J, Zanchi D, Lang UE, Borgwardt S.
Phytomedicine. 2017 Oct 15;34:26-37. doi: 10.1016/j.phymed.2017.07.008.

Tea (Camellia sinensis) is a widely used plant for ethnopharmacological use mainly due to the presence of bioactive components such as phenolic compounds (gallic acid, p-coumaric acid and caffeic acid), purine alkaloids (theobromine, caffeine and theophylline), anthocyanins, flavonol glycosides (kaempferol, myricetin and quercetin), flavonoids (catechins).

The color varieties are mainly due to differences in treatment, climate, but basically the variations between plants are few.

It is grown in:

• India
• Cina
• Sri Lanka
• Kenya
• Indonesia

The most common are:

• black
• green
• oolong
• red

The characteristic scent of tea seems to be influenced by the jasmonic acid present in the leaves (1).

When tea is taken to prevent or combat disease, attention should be paid to doses and, as with almost all herbs, ingestion of large amounts may be toxic. When the tea is taken for therapeutic purposes for cardiovascular diseases, diabetes and more, the best results are obtained in people who consume 3-4 cups of tea (600-900 mg of catechins) per day (2).

This study believes that green tea plays a neuroprotective role in neurodegenerative diseases and memory decline with old age, such as Alzheimer's disease (3).

A polysaccharide composed only of glucose has been isolated from the green lemon and the authors of the discovery explain how this polysaccharide can be a potential therapeutic agent on prostate cancer (4).

Oral administration of green tea extract exercised cardioprotective activity and prevented  doxorubicin induced cardiotoxicity by accelerating heart antioxidant defense mechanisms and down regulating the lipid peroxidation levels to the normal levels (5).

The protective effect against hematologic neoplasms, especially acute myeloid leukemias has been suggested (6).

Green tea studies

References_________________________________________________

(1) Influence of Chloroplast Defects on Formation of Jasmonic Acid and Characteristic Aroma Compounds in Tea (Camellia sinensis) Leaves Exposed to Postharvest Stresses.  Li J, Zeng L, Liao Y, Gu D, Tang J, Yang Z.  Int J Mol Sci. 2019 Feb 27;20(5). pii: E1044. doi: 10.3390/ijms20051044.

(2) Studies on the Prevention of Cancer and Cardiometabolic Diseases by Tea: Issues on Mechanisms, Effective Doses, and Toxicities.  Yang CS, Zhang J. J Agric Food Chem. 2019 May 15;67(19):5446-5456. doi: 10.1021/acs.jafc.8b05242.

(3) Green tea supplementation produces better neuroprotective effects than red and black tea in Alzheimer-like rat model.  Schimidt HL, Garcia A, Martins A, Mello-Carpes PB, Carpes FP.  Food Res Int. 2017 Oct;100(Pt 1):442-448. doi: 10.1016/j.foodres.2017.07.026.

(4) Anti-tumor activity and the mechanism of a green tea (Camellia sinensis) polysaccharide on prostate cancer.  Yang K, Gao ZY, Li TQ, Song W, Xiao W, Zheng J, Chen H, Chen GH, Zou HY.  Int J Biol Macromol. 2019 Feb 1;122:95-103. doi: 10.1016/j.ijbiomac.2018.10.101.

(5) Cardioprotective effect of green tea extract on doxorubicin-induced cardiotoxicity in rats. Khan G, Haque SE, Anwer T, Ahsan MN, Safhi MM, Alam MF.  Acta Pol Pharm. 2014 Sep-Oct;71(5):861-8.

(6) Green tea consumption and risk of hematologic neoplasms: the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study).  Takada M, Yamagishi K, Iso H, Tamakoshi A.  Cancer Causes Control. 2019 Aug 26. doi: 10.1007/s10552-019-01220-z.