The Healing and Protective Properties of Green Tea
By: Brittany Molnar
4/1/20249 min read
When I was in college I remember during every organic chemistry lecture, my teacher was always sipping on his green tea. Well actually, I didn’t know that's what it was until we had our lecture on antioxidants. I recall him putting so much emphasis on its antioxidant power that it stuck with me. So of course when I had to pick an herb topic for my medicinal herbs class, I chose green tea for my 23 page long paper. I thought I’d put some of the useful information I gained from my research into this blog post so you can enjoy some knowledge and insights as to why I’m a huge fan of green tea. After reading, you may just want to consider adding it into your wellness rituals.
History as Folk Medicine
The history of the tea plant's journey is reflected in its name Camellia Sinensis. Camellia indicates its woody bush like nature, while Sinensis signifies that it is of Chinese origin [1]. In 2016, plant matter containing molecular components of tea were found in northeastern China and Tibet, and found to be carbon dated 2,100 years old. Scientists continue to look for clues in the plant's DNA to reach further back in search of the domestic history of tea [1]. Tea has been used in traditional Chinese medicine for thousands of years, and is also mentioned in the Tang and Song Dynasties. In the Cha Jing or tea bible, by Lu Yu from the Tang Dynasty, production, preparation, and health benefits were described in detail. It was described as a medicine in the Xin Xiu Ben Cao of the Tang Dynasty as being “...bitter and sweet, slightly cold and with no toxicity. It has functions of pushing down the perverse rising qi; eliminating thirst, heat, and phlegm” In the historical Ben Cao Gang Mu by Li Shizhen of the Ming Dynasty, they describe tea as being bitter and cold which lowers the fire. Fire being inflammation, which we know to be the contributor of many diseases [2].
Green tea has such a long history of usage that there is more than one legend based on its discovery. The Father of Chinese medicine- Shennong is said to have discovered and classified some 365 natural medicines and was well known for his works in The Divine Farmer's Herb Root Classic, which was said to be the earliest Chinese pharmacopeia compiled thousands of years after his existence during the western Han Dynasty. According to legend, one of his discoveries was tea, which he apparently discovered by accident in 2437 BC when tea leaves landed in his cauldron of boiling water. Shennong was known to have taste tested hundreds of herbs and tea was one of his greatest discoveries as it proved to be the antidote for almost 70 varieties of poisons [3]. Another popular folklore legend says that in around 500 AD, the buddhist monk Bodhidharma spent 9 years silently meditating awake and focused, while facing the wall of a cave. This eventually led him to doze off, which angered him so greatly that he ripped his eyelids off and threw them to the ground. His flesh on the ground was the site at which the first tea plant began to grow. Making the perfect beverage for meditating monks [1].
Effects
Promotes Healthy Flora
Green tea is a great ingredient to add to mouthwash as it inhibits plaque as well as harmful bacteria such as the growth and adherence of porphyromonas gingivalis. Ethyl Acetate in Green tea has been shown to inhibit cavity causing bacteria such as Escherichia coli, Streptococcus salivarius, and Streptococcus mutans [4]. Green tea also promotes beneficial bacteria and improves gut microflora. For example, 400 mg of green tea polyphenols 3 times per day has shown to promote Lactobacillus and Bifidobacter growth, while inhibiting Clostridium perfringens and Clostridium difficile growth and preventing their associated diarrheal symptoms. Interestingly, this effect also plays a role in colon cancer prevention [4]. Other diarrheal diseases from bacteria such as vibrio cholerae, salmonella typhimurium/typhi have also been inhibited by green tea extract [4].
Offers Various Protective Benefits
Studies have found various protective properties of green tea. These include prevention of cardiovascular pathologies and protection against cancer. Its consumption provides catechins and polyphenols which protect the heart by preventing oxidation of LDL cholesterol [4]. In relation to cancer, well controlled clinical studies have shown the cancer preventive effects of green tea and demonstrated dose dependent increased apoptosis in cancer cells and decreased proliferation with in vitro studies when exposed to polyphenols, in particular EGCG. Tea polyphenols caused growth arrest in tumor cells during the cell cycle's GI phase. The antioxidant, chemoprotective, and antiproliferative activity of green tea is primarily due to its polyphenols, two of which I will discuss in more detail below.
Top Bioactive Molecules and Clinical Trials
EGCG
A popular active compound found in green tea and a number of other plants is a type of catechin known as EGCG or epigallocatechin gallate. This compound is a phenolic antioxidant that protects cells from free radical damage and oxidation. It’s classified as an anticarcinogenic, antimutagenic and neuroprotective agent [5]. EGCG is found in the polyphenols of green tea and is associated with its anticancer effects. In several in vitro studies, EGCG has been shown to decrease proliferation and increase apoptosis in lung, breast, stomach, pancreas, small intestine, and colon cancer cell lines. EGCG in combination with theanine found in green tea also showed to be effective at affecting DOX tumor-cell activity inhibiting DOX cellular efflux by 30.5 % and 19.5 %[4]. Epigallocatechin-3-gallate also shows to be effective in protecting the skin from UV damage that correlates with decreased lipid peroxidation. EGCG specifically protects against UVB exposure and associated skin damage. Protection from acute erythema formation was found with skin application of green tea extract 30 minutes before exposure to UVB [4].
Clinical trial- EGCG on Melanoma
Epigallocatechin-3-gallate is a major component in green tea and has been shown to demonstrate antioxidant, anti-inflammatory, anti-mutagenic, and anticarcinogenic properties. The most deadly form of skin cancer is melanoma. Human melanoma cells aggressiveness is due to their secretion of inflammatory cytokines and chemokines. Since melanoma is an inflammatory condition, targeting inflammation may be useful in melanoma therapeutics. Among these many inflammatory mediators, IL-1B is one of the critical cytokines that mediates progression, tumor growth, immunosuppression, and chemoresistance. The major polyphenol in green tea, epigallocatechin-3-gallate has been shown to inhibit inflammatory cytokines and enzymes such as iNOS, COX2, MMPs, IL-6, IL-8, IL-12, and TNFa. These inflammatory molecules are initiated by IL-1B.
In search of the mechanisms that EGCG uses to inhibit melanoma growth, one study found that EGCG inhibits NFkB and that this reduction in NFkB was associated with the decrease in melanoma cell IL-1B secretion. Investigation was done on whether IL-1B suppression was mediated by inflammasomes since they are involved in IL-1B secretion. They found that treatment with EGCG downregulated the inflammasome component NLRP1 and reduced caspase-1 activation. A key role of inflammasomes in EGCG efficacy was suggested through in vitro and in vivo studies. They showed how halting the expression of NLRP1 abolished EGCG’s inhibition of tumor cell growth. This illustrated that EGCG’s mechanism in melanoma inhibition through inflammasome downregulation leads to decreased IL-1B secretion, which leads to decreased NF-kB activity and decreased cell growth [6].It showed that EGCG is a powerful anti-inflammatory and that mechanisms in EGCG inhibit melanoma growth at physiologic doses of 0.1-1µm and inflammasomes play a role in EGCG efficacy [6]. Stronger effects from EGCG have been shown when combined with vitamin A, red light, dacarbazine, DNA vaccination, interferon, and vorinostat. Therefore, given melanoma's aggressive nature, treatment may involve a combinational therapy which could decrease required doses for either medication as well as adverse effects. This research demonstrates a promising treatment for melanoma as well as application towards other disorders in which IL-1b and inflammasomes play a role. This research also provides data that shows that inflammasome activity should be a target for melanoma treatment [6].
Quercetin
Another active compound found in Green tea flavonoids is known as Quercetin. Quercetin is also found in many plants and fruits such as green vegetables, tomatoes, red grapes, citrus fruits and berries. Although no health claims have been approved by the FDA, several epidemiological studies have shown an inverse relationship between flavonoids and reduced incidence and mortality from cancers and cardiovascular disease. Quercetin is classified as an antioxidant and is a polyphenolic flavonoid. It has potential chemoprotective activity and may produce antiproliferative effects as well as anti-inflammatory and anti-allergy effects. In vitro, Quercetin decreased expression of mutant p53 protein and p21-ras oncogene, inducing cell cycle arrest. It also demonstrated synergy and reversed multidrug resistance in combination with chemotherapy [7].
Clinical Trial- Quercetin on Rheumatoid Arthritis
A study looked at the Effect of Quercetin on Inflammatory Factors and Clinical Symptoms in Women with Rheumatoid Arthritis. One of the most important phenolic compounds found in fruits, vegetables, and other plants, is the bioflavonoid Quercetin. This compound has been shown to have anti-inflammatory properties by inhibiting secretions of inflammatory cytokines such as TNF-a, IL-2 and IFN-g through the regulation of gene expression associated with (NF-kB) transcription factors as well as inhibiting immune cells.This strong antioxidant has been shown to reduce arthritis in previous animal studies as well as reduce pain by nociceptive inhibition in animals and clinically in humans. Rheumatoid arthritis is a common chronic inflammatory disease in which the connective tissues, joints, muscles, tendons, and fibrous tissues are all affected. This disease is more common in women and has a worldwide prevalence of 0.5-1%. Inflammatory changes, cells, and cytokines derived from macrophages such as IL-1B, IL-6 and TNF-a in the synovial structure lead to deformation, atrophy, and pain in the joints as well as muscle distortment, bone erosion and osteoporosis. This causes disabilities that reduce the quality of life and in the long term, lead to death. Inflammation and its relationship with oxidative stress in the body is shown when increased reactive oxygen species (ROS) via activation of NF-kB leads to inflammation, which leads to joint damage. Previous findings showing the antioxidant, anti-inflammatory, and anti-nociceptive effects of quercetin, led to the hypothesis that it could have therapeutic properties to treat rheumatoid arthritis. Therefore, in this study, the effects of quercetin on rheumatoid arthritis were investigated [8].
This study examined effects of quercetin supplementation on rheumatoid arthritis symptoms and severity in women. Out of the 20 patients in each group who completed the study, after the intervention with supplementation, the quercetin group had a reduced number of patients with active rheumatoid arthritis [8]. One of the limitations in this study was that the patients disease was mild to moderate, when efficacy would more likely be reflected in more severe forms. Because of the uncertainty in effects of long term use, caution was used in this study. Therefore, studies with longer duration on more participants are still needed to confirm results. Overall, treatment with quercetin had beneficial effects on disease symptoms and reduced inflammatory hs-TNFa, which plays a role in pain. Positive effects were also shown in disease activity DAS-28, EMS, HAQ score, and PGA. Overall, women with rheumatoid arthritis had improved their well-being with quercetin supplementation [8].
How to Use
Of course the simplest way to enjoy green tea is to brew it in some hot water, but there are so many other ways you can incorporate this lovely antioxidant rich herb into your wellness rituals. You can even use it topically. I really like to use it in my homemade face mask during the summer when my skin needs more TLC after being exposed to the harsh elements. It’s also great for puffy eyes! Just wet some tea bags and place them in the freezer, once chilled, apply to your eyes for a few minutes. If you’re not a big tea drinker but still want to incorporate it into your diet you can also try adding some matcha to your baked goods, such as homemade muffins, bread, or pancakes. I also really enjoy adding it to my smoothies.
1.Drew, L. (2019) Genetic studies of today’s tea trees are providing clues to how the plant was first domesticated. Nature, Vol 566. Retrieved from: https://media.nature. com/original/magazine-assets/d41586-019-00395-4/d41586-019-00395-4.pdf doi:10.1038/d41586-019-00395-4
2.Yang, C. S., Chen, G., & Wu, Q. (2014). Recent scientific studies of a traditional chinese medicine, tea, on prevention of chronic diseases. Journal of traditional and complementary medicine, 4(1),17–23. Retrieved from: https://doi.org/10.4103/ 2225-4110.124326
3.Hubei (2008) Shennong Legend. Hubei - The people's government of hubei province. Serial No: I-49. Retrieved from: http://en.hubei.gov.cn/culture/intangible/ 201508/t20150821_707605.shtml
4.Gruenwald, J., Brendler, T., & Jaenicke, C. (Eds.). (2007). Green Tea. In PDR for Herbal Medicines (4th ed., pp. 414-422). Montavale, NJ: Thomson.
5.National Center for Biotechnology Information. PubChem Database. (2020) (-)-Epigallocatechin gallate. PubChem. CID=65064. Retrieved from:https://pubchem.ncbi.nlm.nih.gov/compound/65064
6.Ellis, L. Z., Liu, W., Luo, Y., Okamoto, M., Qu, D., Dunn, J. H., & Fujita, M. (2011). Green tea polyphenol epigallocatechin-3-gallate suppresses melanoma growth by inhibiting inflammasome and IL-1β secretion. Biochemical and biophysical research communications, 414(3), 551–556. Retrieved from: https://doi.org/10.1016/j.bbrc.2011.09.115
7.National Center for Biotechnology Information. PubChem Database. (2020) Quercetin. PubChem. CID=5280343. Retrieved from: https://pubchem.ncbi.nlm.nih.gov /compound/Quercetin
8.Javadi, F. MSc, Ahmadzadeh, A. MD, Eghtesadi, S. PhD, Aryaeian, N. PhD, Zabihiyeganeh, M. MD, Foroushani, A. R. PhD, & Jazayeri, S. MD, PhD (2016): The Effect of Quercetin on Inflammatory Factors and Clinical Symptoms in Women with Rheumatoid Arthritis: A Double-Blind, Randomized Controlled Trial, Journal of the American College of Nutrition. Retrieved from: https://www. uab.edu/medicine/rheumatology/images/JY_-_Javade_et_al_2016.pdf doi:10.1080/07315724.2016.1140093