Inhibition of platelet aggregation by olive oil phenols via cAMP-phosphodiesterase

• Published in: British journal of nutrition 2008-05, Vol.99 (5), p.945-951
• Main Authors: Dell'Agli, Mario, Maschi, Omar, Galli, Germana V., Fagnani, Rossana, Dal Cero, Esther, Caruso, Donatella, Bosisio, Enrica
• Format: Article
• Language: English
• Subjects: 3',5'-Cyclic-AMP Phosphodiesterases - antagonists & inhibitors; 3',5'-Cyclic-AMP Phosphodiesterases - physiology; apigenin; Biochemistry; Biological and medical sciences; Biological effects; Blood clots; blood platelets; Blood Platelets - enzymology; cAMP-phosphodiesterase; Cells, Cultured; Dose-Response Relationship, Drug; Enzymatic activity; enzyme inhibition; Enzyme Inhibitors - pharmacology; Enzymes; extracts; Feeding. Feeding behavior; Flavonoids; Fundamental and applied biological sciences. Psychology; Humans; hydroxytyrosol; Ionization; Liquid chromatography; luteolin; Nutrition; oleuropein aglycone; Olive Oil; Olive oil extracts; Phenols; Phenols - analysis; Phenols - pharmacology; Phosphodiesterases; Plant Extracts - pharmacology; Plant Oils - chemistry; Plant Oils - pharmacology; Platelet aggregation; Platelet Aggregation - drug effects; Platelet Aggregation Inhibitors - pharmacology; protective effect; quercetin; tyrosol; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114507837470

The aim of the present study was to confirm that olive oil phenols reduce human platelet aggregability and to verify the hypothesis that cAMP- and cGMP- phosphodiesterases (PDE) could be one of the targets of the biological effect. Four extracts from oils characterized by a high phenol content (HPE), and low phenol levels (LPE) were prepared and analyzed quali- and quantitatively by HPLC-UV and electrospray ionization–MS/MS. Human washed platelets stimulated with thrombin were used for the aggregation assay. Human platelet cAMP-PDE and recombinant PDE5A1 were used as enzyme source. Platelet aggregation and enzyme activity were assayed in the presence of HPE, LPE and individual phenols. The phenol content of HPE ranged between 250 and 500 mg/kg, whereas the LPE content was 46 mg/kg. The compounds identified were hydroxytyrosol (HT), tyrosol (TY), oleuropein aglycone (OleA) and the flavonoids quercetin (QU), luteolin (LU) and apigenin (AP). OleA was the most abundant phenol (range 23·3 to 37·7 %) and LU was the most abundant flavonoid in the extracts. Oil extracts inhibited platelet aggregation with an 50% inhibitory concentration interval of 1·23–11·2 μg/ml. The inhibitory effect of individual compounds (10 μm) including homovanillyl alcohol (HVA) followed this order: OleA>LU>HT = TY = QU = HVA, while AP was inactive. All the extracts inhibited cAMP-PDE, while no significant inhibition of PDE5A1 (50μg/ml) was observed. All the flavonoids and OleA inhibited cAMP-PDE, whereas HT, TY, HVA (100 μm) were inactive. Olive oil extracts and part of its phenolic constituents inhibit platelet aggregation; cAMP-PDE inhibition is one mechanism through which olive oil phenols inhibit platelet aggregation.