Abstract
Cold-pressed, non-raffinated evening primrose oil was found to contain lipophilic radical scavengers. A highly enriched fraction of these compounds could be obtained from the oil by extraction with aqueous ethanol and subsequent liquid-liquid partitioning with petroleum. LC-DAD-MS analysis revealed that the fraction contained three aromatic compounds with identical UV and ESI-MS spectra. The compounds were isolated by RP-HPLC and their structures established by chemical and spectroscopic means as 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid. The morolic acid derivative was a new compound. The three esters exhibited pronounced radical scavenging activity against the stable 2,2-diphenyl-1-picrylhydrazyl radical and were potent inhibitors of neutrophil elastase and cyclooxygenase-1 and -2 in vitro. Commercial samples of evening primrose oils contained only traces of these lipophilic antioxidants.
MeSH terms
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Antioxidants / analysis
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Betulinic Acid
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Chromatography, High Pressure Liquid
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Chromatography, Liquid
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Cyclooxygenase Inhibitors / analysis
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Cyclooxygenase Inhibitors / pharmacology*
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Enzyme Inhibitors / analysis
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Enzyme Inhibitors / pharmacology*
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Esters / pharmacology
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Fatty Acids, Essential / chemistry*
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Fatty Acids, Essential / pharmacology*
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Free Radical Scavengers / analysis
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Free Radical Scavengers / pharmacology*
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Leukocyte Elastase / antagonists & inhibitors*
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Linoleic Acids
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Mass Spectrometry / methods
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Oenothera biennis
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Oleanolic Acid / analysis
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Pentacyclic Triterpenes
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Plant Oils
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Triterpenes / chemistry
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gamma-Linolenic Acid
Substances
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Antioxidants
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Cyclooxygenase Inhibitors
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Enzyme Inhibitors
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Esters
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Fatty Acids, Essential
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Free Radical Scavengers
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Linoleic Acids
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Pentacyclic Triterpenes
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Plant Oils
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Triterpenes
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morolic acid
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evening primrose oil
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Oleanolic Acid
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gamma-Linolenic Acid
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Leukocyte Elastase
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Betulinic Acid