There are two very distinguishing traits of being British: discussing the weather and consuming tea. Often together. Nothing can beat a good cup of tea, especially after being out in the torrential rain we’ve been experiencing. In light of the Science Brainwaves collaboration with TeaSoc, I wanted to find out a bit more about the science of tea. So grab a cuppa, and read on…
Tea is derived from the Camellia sinensis plant, and there are four main types of tea: black, green, oolong and white. Originally from China and southern Asia, tea has travelled all over the world to become one of the most popular drinks in the world, after good old water. Tea is enriched in polyphenols (which are antioxidants and scavenge free radicals). The fact that tea is rich in antioxidants has often been exploited in beauty and health trends, particularly green tea, which appears to be packed into practically everything, including ice cream, facial moisturisers and even biscuits.
However, it appeared drinking tea did for us than just giving radiant skin, after a particular study conducted in Japan in 2009, by Naganuma et al. showed that there seemed to be a link between drinking green tea and cases of cancers arising from the blood and bone marrow, e.g. lymphomas, myelomas, etc. where a population in rural Japan, who consumed more green tea, had lower incidences of certain blood cancers.
Further research elucidated green tea contains epigallocatechin-3-gallate (EGCG), which is a potent group of polyphenols. This has been shown in cell culture studies, to be able to induce cell death in various tumour cells, and also reduce the “anti-apoptotic” proteins (these tend to resist cell death, and are often increased in many cancers).
This small molecule was then investigated as a potential cancer treatment, however although natural and safe to drink, researchers found that EGCG as a therapy caused side effects elsewhere, when tested on mice models.
In a study comparing EGCG from green tea, and Honokiol (a compound from Magnolia flower- Magnolia grandiflora) and their ability at causing cell death in various tumour cell lines, results showed that Honokiol was more efficient at inducing cell death, and was more effective at binding to the target molecule. Other studies also showed that in certain cancers such as breast cancer, green tea consumption had no effect.
It is still being debated to what extent tea has anti-cancer properties, but further research is required to comment on whether there are definite anti-cancer benefits to be drawn from tea. Having said that, even if tea directly cannot be a drug for treating cancers, scientists have utilised tea polyphenols to create nanoparticle micelles, to help deliver chemotherapy drugs- acting like a smart coating. This has shown success in mice models, without any systematic side effects. Tea polyphenols have also been implicated with nanoparticles called “Quantum dots” which can fluoresce, and bind to cancer cells, and be used for medical imaging.
Overall, there is more than meets the eye with tea, possibly harbouring fantastic potential not only in the fields of cancer therapeutics, but also imaging, solar cells, agriculture, etc.
Additional interesting read:
Brewing Nanotechnology From Tea: https://www.nature.com/articles/d41586-019-00401-9
Engelhardt, U. H. (2010). Chemistry of tea. In L. Mander, & H. B. Liu (Eds.), Comprehensive natural products II: Chemistry and biology (Vol. 3, pp. 999e1032). London: Elsevier Applied Science Publishers Ltd.
Naganuma T., Kuriyama S., Kakizaki M., et al.; Green Tea Consumption and Hematologic Malignancies in Japan: The Ohsaki Study (2009) , American Journal of Epidemiology, Volume 170, Issue 6, 15 September 2009, Pages 730–738, https://doi.org/10.1093/aje/kwp187
Rady, I., Mohamed, H., Rady, M., Siddiqui, I. A., & Mukhtar, H. (2020). Egyptian Journal of Basic and Applied Sciences Cancer preventive and therapeutic effects of EGCG , the major polyphenol in green tea. Egyptian Journal of Basic and Applied Sciences, 5(1), 1–23. https://doi.org/10.1016/j.ejbas.2017.12.001
Miyata, Y., Matsuo, T., Araki, K., Nakamura, Y., Sagara, Y., Ohba, K., & Sakai, H. (2018). Anticancer Effects of Green Tea and the Underlying Molecular Mechanisms in Bladder Cancer. Medicines (Basel, Switzerland), 5(3), 87. doi:10.3390/medicines5030087
Martin, S., Lamb, H. K., Brady, C., Lefkove, B., Bonner, M. Y., Thompson, P., … Arbiser, J. L. (2013). Inducing apoptosis of cancer cells using small-molecule plant compounds that bind to GRP78. British Journal of Cancer, 109(2), 433–443. https://doi.org/10.1038/bjc.2013.325
Yang, C. S., Wang, X., Lu, G., & Picinich, S. C. (2009). Cancer prevention by tea: animal studies, molecular mechanisms and human relevance. Nature Reviews Cancer, 9, 429. Retrieved from https://doi.org/10.1038/nrc2641
Zhang, H., Yi, Z., Sun, Z., Ma, X., & Li, X. (2017). Functional nanoparticles of tea polyphenols for doxorubicin delivery in cancer treatment. Journal of Materials Chemistry B, 5(36), 7622–7631. https://doi.org/10.1039/C7TB01323J