Green Tea: Origins of the World’s Most Popular Infusion

Published on August 09, 2017 by Dr. Jonathan Ferrier

Tea is an evergreen shrub grown to make Black tea, Oolong tea, and Green tea. Green tea is made by steaming and drying the leaves and leaf buds to prevent oxidation; unlike Black tea and Oolong tea which are fermented and semi-fermented, respectively. 

  Fermentation oxidizes the phenolic compounds and darkens the infusion’s hue. Since Green teas provide approximately twice the amount of beneficial catechins found in black teas, Green tea has an auspicious future in food, health, research and development.

Known to botanists as Camellia sinensis (L.) Kuntze, Tea was first scientifically described by the father of modern taxonomy, Carl Linnaeus- hence the ‘(L.)’. Camellia sinensis, the name, was later refined by Otto Kuntze, a German apothecary who also distributed essential oils from his factory. Perhaps Kuntze’s appreciation for Tea’s character astringency and flavour, from it’s tannins and volatile oils, including monoterpene alcohols (geraniol, linalool) and aromatic alcohols (benzyl alcohol, 2-phenylethanol), led him to improve the species’ taxonomy. He described Tea based on it’s native origin - sinensis means ‘from China’[1].

The ritual of drinking Tea is profoundly cosmopolitan, due, undoubtedly, to its purine alkaloids. Alkaloids are a nitrogen containing class of compounds that have a renowned therapeutic and recreational use history. Tea leaves contain one to five percent caffeine, and traces of theophylline, theobromine, and xanthine alkaloids. Together, these alkaloids stimulate the consumer in a fashion similar to cocoa, coffee, or yerba mate, increasing the heart rate, delivering mental clarity, rejuvenating awareness. This chemical nature literally changed the lay of the land as tea was already broadly domesticated throughout most of China’s provinces 4000 years ago.

Should one say, “People domesticated Tea.”, or “Tea domesticated people”?   

 That’s a valid question. Caffeine, for instance, is an evolved insecticide to prevent herbivory, yet it is exceedingly sought after by people needing a second-wind, ‘to get them through an afternoon’. Now, Tea has been so extensively cultivated, to identify a truly ‘wild’ specimen today would be seriously difficult. Tea and tea-time is here to stay.

Now, Green tea, is being marketed as a functional supplement or natural health product (NHP). While Green tea was not a typical go-to medicinal in traditional Chinese medicine, its stimulating properties along with its antioxidant benefits, make for a highly practical supplement in today’s NHP industry. Polyphenols, including epigallocatechin gallate (EGCg), epicatechin gallate (ECG), epicatechins (EC), plus flavonoids such as, kaempferol, quercetin, and myricetin, are responsible for the darker brown tannic hue and represent 27   

   percent of the plant’s chemistry. Many of these compounds have anti-cancer, anti-diabetic and anti-inflammation activities and help slow the aging process with cellular protective qualities for tissues and organs. With research and development, Green tea’s short comings and utilities are frequently being expanded upon. For example, research conducted with Green tea indicates that its’ catechins can inhibit the bioavailability of non-heme iron by 79% to 94%; however, catechins’ affinity for iron can also be mitigated by the addition of lemon. The addition of lemon juice, which contains ascorbic acid, is also reported to improve the antioxidant potential of Green tea. Extracts of Green tea leaves are now being combined with other NHPs including Rhodiola rosea L. (Roseroot) extract to produce products that are stimulating, adaptogenic, and protective for today’s energy supplement consumers. As history has demonstrated Green tea is continuing to change the landscape in the way scientists, clinicians, and consumers approach the virtues of natures’ gifts.

[1] Camellia is for Georg Joseph Kamel (Cameli) (1661–1706), a Moravian Jesuit botanist. Modern taxonomy rules do not condone names that do not reflect an organism’s character state(s). Naming a plant after someone is faux pas.

Figures

Green tea’s A) Camellia sinensis line drawing, B) infusion, with the infusion’s aromatic compound C) 2-phenylethanol, antioxidant D) epigallocatechin gallate (EGCG), and alkaloid E) caffeine (Carbon, C: black, Hydrogen, H: white, Oxygen, O: red, Nitrogen, N: blue).

Camellia sinensis, Tea, cultivated in rural southwest Rwanda © Jonathan Ferrier.

References

Dewick P. Medicinal natural products: a biosynthetic approach.

Kew Library Art and Archives, Digital Image © Board of Trustees, RBG Kew http://             creativecommons.org/licenses/by/3.0/

Cabrera C. Beneficial Effects of Green Tea—A Review. Journal of the American College of            Nutrition, Vol. 25, No. 2, 79–99 (2006).

Dr. Jonathan Ferrier, PhD is our newest contributor on Dr.Nibber.com and ethnobotanist extraordinaire, retelling the stories of plants.