Effects of virgin olive oil phenolics on scavenging of reactive nitrogen species and upon nitrergic neurotransmission

• Published in: Life sciences (1973) 2001-07, Vol.69 (10), p.1213-1222
• Main Authors: de la Puerta, Rocı́o, Domı́nguez, M Eugenia Martı́nez, Ruı́z-Gutı́errez, Valentina, Flavill, Jenny A., Hoult, J.Robin S.
• Format: Article
• Language: English
• Subjects: Animals; Anococcygeus muscle; Antioxidants - chemistry; Antioxidants - pharmacology; Caffeic Acids - isolation & purification; Caffeic Acids - pharmacology; Dose-Response Relationship, Drug; Free Radical Scavengers - chemistry; Free Radical Scavengers - pharmacology; Iridoids; Male; Muscle Relaxation - drug effects; Muscle, Smooth - drug effects; Muscle, Smooth - innervation; Neural Conduction - drug effects; Nitrates - chemical synthesis; Nitrates - metabolism; Nitrergic neurotransmission; Nitric oxide; Nitric Oxide - metabolism; Nitroprusside - metabolism; Olive Oil; Peroxynitrite; Phenolic antioxidants; Phenols - chemistry; Phenols - pharmacology; Phenylethyl Alcohol - analogs & derivatives; Phenylethyl Alcohol - isolation & purification; Phenylethyl Alcohol - pharmacology; Plant Oils - chemistry; Plant Oils - pharmacology; Pyrans - isolation & purification; Pyrans - pharmacology; Rats; Rats, Wistar; Virgin olive oil
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/S0024-3205(01)01218-8

The major phenolics from the polar fraction of virgin olive oil (caffeic acid, oleuropein, tyrosol and hydroxytyrosol) have well-established antioxidant activities but their effects on reactive nitrogen species and nitrergic neurotransmission have not been fully investigated. The three catechol compounds were active as scavengers of nitric oxide generated spontaneously from the decomposition of sodium nitroprusside (≈50% inhibition achieved at 75 μM), and had similar ability to scavenge chemically generated peroxynitrite, as determined by an α 1-antiproteinase inactivation assay (67.2 %–92.4 % reduction when added at 1mM). Tyrosol was less active in these tests, but does not possess the catechol functionality. Despite their ability to interact with chemically prepared nitric oxide, neither oleuropein nor hydroxytyrosol at 5 μM altered NO· -mediated relaxations of the nerve-stimulated rat anococcygeus preparation, but this may be because the nitrergic transmitter is protected from the effects of externally applied scavengers. In conclusion, the phenolics found in virgin olive oil possess ability to scavenge reactive oxygen and nitrogen species that are implicated in human pathologies, but their impact may be restricted to those species present in the extracellular environment.