Antioxidant activity of green tea leaves (Camellia sinensis L.) liquid extracts

Nowadays, it has been proved that cardiovascular diseases are caused by free radicals due to imbalance between antioxidant and prooxidant systems. Antioxidants are applied for scavenging free radicals in order to prevent and stop oxidative stress. Leaf of green tea is a source of potent antioxidants of phenolic nature which can be used for elaborating dietary supplements, cosmetology products and medicine with antioxidant activity. The aim of study was to determine antioxidant activity of green tea leaves (Camellia sinensis L.) liquid extracts obtained by the 96, 60, 40, 20% ethanol and distilled water. The antioxidant activity of these extracts was measured by potentiometric method. The results showed that 96% ethanolic extract had the significant value of antioxidant activity compared to the other extracts. The 60% ethanolic extract had the greatest amount of phenolic compounds among extracts, however, it is not possessing a potent antioxidant activity due to presence of carbohydrates, amino acids and organic acids in extract which are not have the antioxidant activity. The very high correlation was found between antioxidant activity and content of phenolic compounds.