Cloning of a novel O-methyltransferase from Camellia sinensis and synthesis of o-methylated EGCG and evaluation of their bioactivity.

The gene of a novel O-methyltransferase was isolated from tea cultivars (Camellia sinensis L.). Using the recombinant enzyme, O-methylated (−)-epigallocatechin-3-O-gallate (EGCG) in all cases were synthesized. EGCG and the synthesized O-methylated EGCGs including (−)-epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3′′Me), (−)-epigallocatechin-3-O- (4-O-methyl)-gallate(EGCG4′′Me), (−)-epigallocatechin-3-O-(3,5-O-dimethyl)-gallate (EGCG3′′,5′′diMe), and (−)-3-O-methyl-epigallocatechin-3-O-(3,5-O-dimethyl)-gallate (EGCG3′,3′′,5′′triMe) were assayed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and antibacterial activity. EGCG was the most effective of the O-methylated EGCGs. The antiallergic effects of EGCG and the other O-methylated EGCGs were measured by conducting histamine release assays using bone marrow-derived mouse mast cells, and the order of potency was EGCG3′,3′′,5′′triMe = EGCG3′′,5′′diMe > EGCG3′′Me > EGCG. These results indicated that reducing the number of hydroxyl gro...