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 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.
Kirita
Masanobu
M
Research Laboratories for Fundamental Technology of Food, Asahi Breweries Limited, Moriya-shi, Ibaraki, Japan. masanobu.kirita@asahibeer.co.jp
Honma
Daiki
D
Tanaka
Yoshihisa
Y
Usui
Shinya
S
Shoji
Toshihiko
T
Sami
Manabu
M
Yokota
Toyokazu
T
Tagashira
Motoyuki
M
Muranaka
Atsuya
A
Uchiyama
Masanobu
M
Kanda
Tomomasa
T
Maeda-Yamamoto
Mari
M
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
D018926:Anti-Allergic Agents; D000900:Anti-Bacterial Agents; D016166:Free Radical Scavengers; D010940:Plant Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D011497:Protein O-Methyltransferase