title: Cloning of a novel O-methyltransferase from Camellia sinensis and synthesis of o-methylated EGCG and evaluation of their bioactivity.
abstract: 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 groups decreases the effectiveness of DPPH radical scavenging and antibacterial activity. In contrast, the inhibition of histamine release was potentiated by an increase in the number of methyl groups in EGCG, especially in the galloyl moiety.
authors.affiliation: Research Laboratories for Fundamental Technology of Food, Asahi Breweries Limited, Moriya-shi, Ibaraki, Japan. masanobu.kirita@asahibeer.co.jp
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kirita
authors.forename: Daiki
authors.initials: D
authors.lastname: Honma
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Shinya
authors.initials: S
authors.lastname: Usui
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shoji
authors.forename: Manabu
authors.initials: M
authors.lastname: Sami
authors.forename: Toyokazu
authors.initials: T
authors.lastname: Yokota
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Tagashira
authors.forename: Atsuya
authors.initials: A
authors.lastname: Muranaka
authors.forename: Masanobu
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Kanda
authors.forename: Mari
authors.initials: M
authors.lastname: Maeda-Yamamoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018926:Anti-Allergic Agents / Q000737:chemistry / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000187:drug effects / Q000276:immunology; D028241:Camellia sinensis / Q000201:enzymology* / Q000235:genetics; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D003001:Cloning, Molecular; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects; D051379:Mice; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011497:Protein O-Methyltransferase / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D018926:Anti-Allergic Agents; D000900:Anti-Bacterial Agents; D016166:Free Radical Scavengers; D010940:Plant Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D011497:Protein O-Methyltransferase