Abstract
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.
Copyright © 2010 Elsevier Ltd. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antioxidants / chemistry
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Catalysis
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Catechols / chemistry
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Cinnamates / chemical synthesis
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Cinnamates / chemistry*
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Cinnamates / pharmacology
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Depsides / chemical synthesis
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Depsides / chemistry*
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Depsides / pharmacology
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Enzyme Inhibitors / chemical synthesis
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Enzyme Inhibitors / chemistry*
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Enzyme Inhibitors / pharmacology
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Flavonoids / chemistry
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Iron / chemistry*
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Lamiaceae / chemistry*
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Magnetic Resonance Spectroscopy
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Molecular Conformation
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Monophenol Monooxygenase / antagonists & inhibitors*
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Monophenol Monooxygenase / metabolism
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Oxidation-Reduction
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Phenols / chemistry
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Polyphenols
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Rosmarinic Acid
Substances
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Antioxidants
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Catechols
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Cinnamates
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Depsides
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Enzyme Inhibitors
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Flavonoids
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Phenols
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Polyphenols
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Iron
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Monophenol Monooxygenase
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catechol