Natural products, mostly plants, and their constituents have been employed in the treatment of ailments since ancient times, and their function in health management is well-known in Asian countries and beyond. Natural products or plant seeds and fruits are extensively utilized in the Arab world to heal diseases, and many plants are recommended for disease therapy, including dates fruits, olive fruits, and black seeds. Medicinal herbs and their constituents, such as olive fruits/oil, dates fruits, and Nigella sativa, has previously been shown to have anti-cancer properties by modulation of numerous biological activities. Green tea, on the other hand, is a beverage derived from the Camellia sinensis plant that is widely consumed around the world. Green tea is made by drying the leaves through pan-frying to prevent oxidation. This helps to keep the colour of the leaves intact. Also, since green tea is not fermented, it is able to keep in an important molecule called polyphenols. Green tea and its contents have been used to regulate health since ancient times by modulating biological processes such as molecular and metabolic pathways.
Green tea’s polyphenol concentration contributes to its health-promoting properties. Catechins are the primary ingredients of green tea, with epigallocatechin gallate (EGCG) being one of the most effective catechins. Epigallocatechin gallate (EGCG) has been shown to have anticancer properties via modulating signalling pathways and also playing a function in the downregulation of proteins implicated in cancer cell invasiveness.
Mechanisms of action of Green tea in cancer prevention
Although green tea has an important role in illness prevention, the exact mechanism of action is still being investigated. The following are some of the probable mechanisms of action of green tea in cancer prevention and progression:
- Green tea inhibits multiple tumour-inducing pathways, hence controlling the growth and progression of tumours.
- Green tea inhibits angiogenesis, activates tumour suppressor genes, and inhibits other transcription factors involved in cancer formation and progression because of its chemopreventive effects
- Due to its high antioxidant capacity, it plays a function in neutralising free radicals and preventing macromolecule damage, thus preventing tumour development.
- Another way that green tea may help to prevent cancer is by modulating genes involved in tumour initiation, progression, and promotion.
Anticancer Properties of Green Tea via Modulating Cell Signaling Pathways
Cancer is a complex disease that includes genetic and metabolic changes. The current therapy method is costly, and it also disrupts several cell signalling pathways. Disease management with natural remedies, particularly from plants, is less expensive and has fewer harmful effects. Various medicinal plants or natural products have exhibited anticancer effects through modulating cell signalling pathways and other biological functions.
Green tea and its constituents play a vital role in cancer prevention via activation/inactivation of genetic pathways, according to previous findings based on clinical trials and animal models.
- Green Tea’s Effect on Apoptosis
The effect of green tea polyphenols, particularly epigallocatechin-3-gallate, on the induction of apoptosis and cell cycle regulation in human and mouse carcinoma cells was investigated, with the conclusion that green tea may protect against cancer by causing cell cycle arrest and inducing apoptosis. A critical evaluation of the current scientific research on the effects of green tea polyphenols and their main ingredient EGCG on prostate cancer signalling pathways.
- Green Tea’s Angiogenesis Effects
Angiogenesis is critical in the formation and progression of tumours. Angiogenesis inhibition is the most critical stage in cancer prevention and treatment. Treatment of nude mice with EGCG, a component of green tea, inhibited the development, vascularity, and proliferation of human colon cancer xenografts in previous investigations.
Green tea constituent EGCG plays a crucial role in the inhibition of tumour cells by decreasing the activation of signalling pathways, consequently inhibiting breast cancer tumour development, proliferation, migration, and angiogenesis.
Several other studies have been conducted to understand the cancer prevention effect of green tea by activation or inactivation of other genetic signalling pathways too.
Several in vivo and in vitro studies have proven that green tea and its compounds, such as EGCG, have a health-promoting effect at a certain dose by modulating several biological functions. Green tea/EGCG overdose, on the other hand, causes severe effects such as acute liver failure/hepatotoxicity due to changes in liver enzymes.
Future of Green Tea in cancer treatment
Green tea and its contents were found to have an anticancer effect in animal models and cell lines via regulating cell signaling pathways such as angiogenesis, apoptosis, and transcription factor. Extensive research using animal models may aid in determining the specific mechanism of action as well as the level of toxicity/side effect without compromising therapeutic potential. Furthermore, a thorough investigation of green tea and its contents based on clinical trials would be extremely beneficial in the development of new anticancer medications.