Omnia SanaCommon names in 19 European languages →
The complete database record: 3 documented constituents, 6 pharmacological actions, 11 traditional / indicated uses, with 22 cited sources.
Botanical Description
Evergreen shrub or small tree with glossy, dark green, leathery, finely toothed leaves. Small, fragrant, white flowers with a prominent central boss of yellow stamens are borne singly or in small clusters in the leaf axils. Commercial tea is made from the young leaves and unopened leaf buds ('sprouts'), processed differently to yield green, black, white or oolong tea from the same species.[15]
Habitat & Distribution
Native to the subtropical and tropical forests and hillsides of East and South Asia (China, India, Myanmar); cultivated extensively across Asia, Africa and elsewhere on well-drained, acidic upland soils.[15]
Harvesting
The youngest leaves and unopened leaf buds ('flush') are hand- or machine-picked repeatedly through the growing season; how the fresh leaf is subsequently processed (withered, rolled, oxidised, fixed and dried) determines whether it becomes green, black, white or oolong tea.[15]
Key Constituents
Principal antioxidant polyphenols, most concentrated in minimally oxidised green tea; epigallocatechin gallate (EGCG) is the best studied.
Caffeine gives tea its mild stimulant effect; L-theanine, a unique amino acid, is associated with calm alertness and modulates caffeine's effects.
Oxidative polymerisation products of catechins formed during black tea processing, contributing to black tea's colour and its own antioxidant profile.
Pharmacological Actions
Traditional & Indicated Uses
inferred from anti-inflammatory action
inferred from antidiabetic action
more plants for blood sugar / diabetes support →detailed sources →
inferred from anticancer action
more plants for cancer (anticancer research) →detailed sources →
more plants for cardiovascular / heart health →detailed sources →
inferred from neuroprotective action
inferred from antimicrobial action
inferred from anti-inflammatory action
inferred from neuroprotective action
inferred from anti-inflammatory action
Traditional Use & History
Preparations
Young leaf, minimally oxidised, infused in hot water; the least-processed and most-studied form for antioxidant polyphenol content.
Concentrated leaf extract standardised to catechin (e.g. EGCG) content, taken as capsules; used in some clinical studies, though high-dose extracts carry rare hepatotoxicity concerns.
Dosage
The EU herbal monograph on green tea leaf (Camelliae sinensis non fermentatum folium) gives, for adults and elderly, 1.8-2.2 g of the whole or comminuted leaf in 100-150 mL of boiling water as an infusion, 3-5 times daily; a powdered herbal substance at 390 mg three times daily (up to 5 if necessary) is also listed. Contraindicated in gastric and duodenal ulcers, cardiovascular disorders such as hypertension and arrhythmia, and hyperthyroidism. Not recommended under 18 years. Educational reference only, not a prescription.
Safety, Cautions & Contraindications
Generally safe in moderate consumption. High caffeine intake may cause insomnia, anxiety, palpitations, or dependence. Large amounts of green tea extract supplements may be hepatotoxic (rare). May reduce iron absorption if consumed with meals. Avoid very high supplement doses during pregnancy.
Duke (2002) rates tea (Camellia sinensis) as ++ and notes anti-aggregant, antioxidant, anticariogenic, and antibacterial activities at the experimental level (score 1). The catechins (EGCG, ECG) and polyphenols are responsible for the antioxidant and anticancer properties under research investigation. Duke notes that green tea preserves more polyphenols than black tea due to less oxidation. Regular tea consumption is associated with reduced cardiovascular risk. Excess consumption (>10 cups daily) may cause fluoride-related bone changes. Caffeine content is relevant for sleep disturbance, anxiety, and interactions with cardiovascular medications (Duke, 2002).
Herb-Drug Interactions
Harvest Readiness
[16]
[16]
External Identifiers
References & Sources
- Mancini, E., Beglinger, C., Drewe, J., Zanchi, D. et al (2017) 'Green tea effects on cognition, mood and human brain function: A systematic review', Phytomedicine, 34, pp. 26-37. doi:10.1016/j.phymed.2017.07.008 Meta-analysis / review
https://doi.org/10.1016/j.phymed.2017.07.008 - Musial, C., Kuban-Jankowska, A. and Gorska-Ponikowska, M (2020) 'Beneficial Properties of Green Tea Catechins', International Journal of Molecular Sciences, 21(5), pp. 1744. doi:10.3390/ijms21051744 Traditional / reference
https://doi.org/10.3390/ijms21051744 - Ohishi, T., Goto, S., Monira, P., Isemura, M. and Nakamura, Y (2016) 'Anti-inflammatory Action of Green Tea', Anti-inflammatory & Anti-allergy Agents in Medicinal Chemistry, 15(2), pp. 74-90. doi:10.2174/1871523015666160915154443 Traditional / reference
https://doi.org/10.2174/1871523015666160915154443 - Zhao, T., Li, C., Wang, S. and Song, X (2022) 'Green Tea (Camellia sinensis): A Review of Its Phytochemistry, Pharmacology, and Toxicology', Molecules, 27(12), pp. 3909. doi:10.3390/molecules27123909 Meta-analysis / review
https://doi.org/10.3390/molecules27123909 - Filippini, T., Malavolti, M., Borrelli, F., Izzo, A.A., Fairweather-Tait, S.J., Horneber, M. and Vinceti, M (2020) 'Green tea (Camellia sinensis) for the prevention of cancer', Cochrane Database of Systematic Reviews, 3(3), pp. CD005004. doi:10.1002/14651858.CD005004.pub3 Meta-analysis / review
https://doi.org/10.1002/14651858.CD005004.pub3 - Prasanth, M.I., Sivamaruthi, B.S., Chaiyasut, C. and Tencomnao, T (2019) 'A Review of the Role of Green Tea (Camellia sinensis) in Antiphotoaging, Stress Resistance, Neuroprotection, and Autophagy', Nutrients, 11(2), pp. 474. doi:10.3390/nu11020474 Meta-analysis / review
https://doi.org/10.3390/nu11020474 - Bedrood, Z., Rameshrad, M. and Hosseinzadeh, H (2018) 'Toxicological effects of Camellia sinensis (green tea): A review', Phytotherapy Research, 32(7), pp. 1163-1180. doi:10.1002/ptr.6063 Meta-analysis / review
https://doi.org/10.1002/ptr.6063 - Hamilton-Miller, J.M.T (2001) 'Anti-cariogenic properties of tea (Camellia sinensis)', Journal of Medical Microbiology, 50(4), pp. 299-302. doi:10.1099/0022-1317-50-4-299 Meta-analysis / review
https://doi.org/10.1099/0022-1317-50-4-299 - Conde, V.R., Alves, M.G., Oliveira, P.F. and Silva, B.M (2015) 'Tea (Camellia sinensis (L.)): a putative anticancer agent in bladder carcinoma?', Anti-Cancer Agents in Medicinal Chemistry, 15(1), pp. 26-36. doi:10.2174/1566524014666141203143143 Meta-analysis / review
https://doi.org/10.2174/1566524014666141203143143 - Moore, R.J., Jackson, K.G. and Minihane, A.M (2009) 'Green tea (Camellia sinensis) catechins and vascular function', British Journal of Nutrition, 102(12), pp. 1790-1802. doi:10.1017/S0007114509991218 Meta-analysis / review
https://doi.org/10.1017/S0007114509991218 - Gaur, R. and Bao, G.H (2021) 'Chemistry and Pharmacology of Natural Catechins from Camellia sinensis as Anti-MRSA Agents', Current Topics in Medicinal Chemistry, 21(17), pp. 1519-1537. doi:10.2174/1568026621666210524100632 Meta-analysis / review
https://doi.org/10.2174/1568026621666210524100632 - Tafazoli, A. and Tafazoli Moghadam, E (2020) 'Camellia Sinensis Mouthwashes in Oral Care: a Systematic Review', Journal of Dentistry (Shiraz), 21(4), pp. 249-262. doi:10.30476/DENTJODS.2020.83204.1045 Meta-analysis / review
https://doi.org/10.30476/DENTJODS.2020.83204.1045 - Albassam, A.A. and Markowitz, J.S (2017) 'An Appraisal of Drug-Drug Interactions with Green Tea (Camellia sinensis)', Planta Medica, 83(6), pp. 496-508. doi:10.1055/s-0043-100934 Meta-analysis / review
https://doi.org/10.1055/s-0043-100934 - Gramza-Michalowska, A (2014) 'Caffeine in tea Camellia sinensis - content, absorption, benefits and risks of consumption', Journal of Nutrition, Health & Aging, 18(2), pp. 143-149. doi:10.1007/s12603-013-0404-1 Meta-analysis / review
https://doi.org/10.1007/s12603-013-0404-1 - Chacko, S.M. et al (2010) 'Beneficial effects of green tea: a literature review'. Traditional / reference
https://scholar.google.com/scholar?q=Beneficial%20effects%20of%20green%20tea%3A%20a%20literature%20review - Fern, Ken 'Camellia sinensis (Tea) — Useful Temperate Plants'. Available at: https://temperate.theferns.info/plant/Camellia+sinensis Traditional / reference
https://temperate.theferns.info/plant/Camellia+sinensis - European Medicines Agency (HMPC) (2013) 'Community herbal monograph on Camellia sinensis (L.) Kuntze, non fermentatum folium'. Available at: https://www.ema.europa.eu/en/documents/herbal-monograph/final-community-herbal-monograph-camellia-sinensis-l-kuntze-non-fermentatum-folium_en.pdf Traditional / reference
https://www.ema.europa.eu/en/documents/herbal-monograph/final-community-herbal-monograph-camellia-sinensis-l-kuntze-non-fermentatum-folium_en.pdf - Drake, V.J (2015) 'Tea catechins and cardiovascular disease risk', 74(1), pp. 39--46. Traditional / reference
https://scholar.google.com/scholar?q=Tea%20catechins%20and%20cardiovascular%20disease%20risk - Nobre, A.C., Rao, A. and Owen, G.N (2008) 'L-theanine, a natural constituent in tea, and its effect on mental state', pp. 167--168. Traditional / reference
https://scholar.google.com/scholar?q=L-theanine%2C%20a%20natural%20constituent%20in%20tea%2C%20and%20its%20effect%20on%20mental%20state - Duke, J.A (2002) 'Handbook of Medicinal Herbs, Second Edition'. Traditional / reference
https://scholar.google.com/scholar?q=Handbook%20of%20Medicinal%20Herbs%2C%20Second%20Edition - Misaka, S., Yatabe, J., Muller, F., Takano, K., Kawabe, K., Glaeser, H., Yatabe, M.S., Onoue, S., Werba, J.P., Watanabe, H., Yamada, S., Fromm, M.F. and Kimura, J (2014) 'Green tea ingestion greatly reduces plasma concentrations of nadolol in healthy subjects', Clinical Pharmacology and Therapeutics, 95(4), pp. 432-438. doi:10.1038/clpt.2013.241 Randomized trial
https://doi.org/10.1038/clpt.2013.241 - Werba, J.P., Misaka, S., Giroli, M.G., Shimomura, K., Amato, M., Simonelli, N., Vigo, L. and Tremoli, E (2018) 'Update of green tea interactions with cardiovascular drugs and putative mechanisms', Journal of Food and Drug Analysis, 26(2S), pp. S72-S77. doi:10.1016/j.jfda.2018.01.008 Meta-analysis / review
https://doi.org/10.1016/j.jfda.2018.01.008
Selected studies & references
All 20 studies in the Knowledge Finder →
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