On The Chemistry of Green Tea Catechins

Green tea catechins are a group of flavonoids that have been shown to have biological effects in humans and animals. The catechins are absorbed from green tea and then have anti-cancer, cardioprotective and weight loss effects. However, green tea catechins are only partially absorbed, and this partial absorption is a characteristic of flavonoids in general, with only a fraction of the ingested flavonoid being detectable in blood following consumption. Another nuance of green tea catechins is that their ability to act as antioxidants is pH dependant. For example, studies have shown that at an alkaline pH above 8, green tea catechins are very unstable. However, at a lower pH of 4 they are stable. Between these two values stability increases as pH drops. Therefore as the green tea catechins pass into the stomach, they would appear to be stable in structure. However, this structure is chemically altered in the higher pH of the intestine, and this may explain the low absorption rates of parent compounds.

green tea antioxidants catechins

Drinking green tea provides a large amount of green tea catechins to the consumer. However, due to chemical alteration in the intestine, much of the ingested catechin load is not absorbed.

Eat Well, Stay Healthy, Protect Yourself


Zhu, Q. Y., Zhang, A., Tsang, D., Huang, Y. and Chen, Z. Y. 1997. Stability of green tea catechins. Journal of Agricultural and Food Chemistry. 45(12): 4624-4628

About Robert Barrington

Robert Barrington is a writer, nutritionist, lecturer and philosopher.
This entry was posted in Antioxidant, Catechin, Green Tea. Bookmark the permalink.