A novel ring-expanded product with enhanced tyrosinase inhibitory activity from classical Fe-catalyzed oxidation of rosmarinic acid, a potent antioxidative Lamiaceae polyphenol.
The iron-ion catalyzed oxidation of the ethanol solution of rosmarinic acid, a potent antioxidant polyphenol of Lamiaceae (Labiatae) plants, afforded a highly tyrosinase-inhibitory active product. The structure of the active product in the oxidation product mixture was determined using extensive NMR spectroscopy to have a novel oxygen-containing seven-membered ring system. The formation mechanism of the unique ring structure from the catechol part of the rosmarinic acid was proposed.
Graduate School of Integrated Arts and Sciences, University of Tokushima, Tokushima, Japan.
Aya
A
Fujimoto
Yoshimi
Y
Shingai
Mitsuhiro
M
Nakamura
Tomomi
T
Maekawa
Yoshiaki
Y
Sone
Toshiya
T
Masuda
D000975:Antioxidants / Q000737:chemistry; D002384:Catalysis; D002396:Catechols / Q000737:chemistry; D002934:Cinnamates / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D053630:Depsides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D005419:Flavonoids / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D019686:Lamiaceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D059808:Polyphenols; D000097123:Rosmarinic Acid
D000975:Antioxidants; D002396:Catechols; D002934:Cinnamates; D053630:Depsides; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007501:Iron; D014442:Monophenol Monooxygenase; D010636:Phenols; D059808:Polyphenols; D000097123:Rosmarinic Acid; C034221:catechol