Green tea offers so many health benefits that it seems almost magical, but these properties all come down to the chemical constituents of the tea leaf. Green tea from the Camellia sinensis plant are rich in polyphenols accur in all plant foods and play a large role in the beneficial health effects of fruit and vegetables. Polyphnols found in Green tea include flavanols, flavandiols, flavonoids, anthocyanins and phenolic acids. Most of the polyphenols are flavonols, commonly known as catechins. One of the catechins that has been extensively researched is epigallocatechingallate (EGCG), revealing its potent antioxidant, anti-tumour and antimutagenic activities. The antioxidant activity is at least 100 times greater than that of vitamin C and 25 times more effective than that of vitamin E at protecting cells and DNA from damage. Many studies indicate EGCG decreases “bad” cholesterol levels, prevents binding of cancer-causing agents to cellular DNA and helps to neutralize dietary carcinogens.
The reason catechin levels stay high in Green tea is that fermenting the leaves triggers an enzymatic process where some of the flavonols convert to new bioactive constituents, theaflavins and thearubigins. Theaflavins provide Green tea with its characteristic colour and taste and exert beneficial effects on the cardiovascular system, helping to reduce “bad” cholesterol levels. While both the nature and concentration of polyphenols in the unoxidised Green tea have significant effects on the human health, thearubigins also have some potency due to their antioxidant properties. Gallic acid is a phenolic acid that is found in Green tea and has antifungal, antiviral, atringent and antioxidant actions. Some studies have indicated it also has anti-cancer activity and can relax blood vessels.