Evaluation of Catechin and its Derivatives as Antioxidant: Recovery of Growth Arrest of Escherichia coli under Oxidative Conditions

Effects of (+)-catechin, (-)-epigallocatechin gallate and gallic acid on the growth of Escherichia coli K-12 under oxidative conditions were examined. (+)-Catechin did not protect the bacterial growth which was inhibited by H₂O₂, lipid hydroperoxide, paraquat, Cu²⁺, H₂O₂+Cu²⁺ and lipid hydroperoxide+Cu²⁺. Both (-)-epigallocatechin gallate and gallic acid could restore the growth inhibition of E coli K-12 under the same conditions. Radical scavenging activity of (-)-epigallocatechin gallate, which is one of the most abundant components in Japanese green tea (Camellia sinensis L), is likely to be dependent upon the gallic acid group of the compound.