BIOLOGICAL-ACTIVITY OF OLIVE TREE POLYPHE NOLIC COMPOUNDS

The Mediterranean diet as popularized by the Cretan cohort in the seve n country study, is associated with low cardiovascular mortality. The benefits might be due to either high intake of fruits and vegetables r ich in antioxidants or consumption of olive oil rich in oleic acid and phenolic compounds. If the effects of vitamins C, E and beta-carotene have been extensively investigated, little is known about minor compo unds of olive tree, namely dihydroxyphenylethanol and oleuropein. We s tudied their in vitro effects on platelet aggregation, red cell deform ability and peroxidation susceptibility of red cell membrane fatty aci ds. Incubation of platelets with dihydroxyphenylethanol caused a signi ficant decrease in platelet aggregation induced by collagen in conditi on of oxidative stress (from 43.4 +/- 17.5 to 27.6 +/- 16.8). Expositi on of erythrocytes to oleuropein or dihydroxyphenylethanol improved re d cell deformability: the mean transit lime of erythrocytes crossing f ilter pores was significantly decreased (1.27 +/- 0.08 ms vs 1.15 +/- 0.11 ms). Peroxidation susceptibility measured by total volatile perox idation products (ethane and pentane) or by polyunsaturated fatty acid (PUFA) loss was also reduced after preincubation with phenolic produc ts (ethane : 3.71 +/- 0.31 vs 0.38 +/- 0.02 nmol/g Hb, pentane: 7.87 /- 0.45 vs 0.48 +/- 0.03 nmol/g Hb). PUFA : (26.7 +/- 4.5 at baseline, 19.9 +/- 1.4 after peroxidative stress, and 31.8 +/- 3.3 % for protec ted erythrocytes). Polyphenols from olive tree, like those from red wi ne, may therefore contribute to reduce atherogenesis and thrombosis by blocking hyperaggregability of platelets, enhancing red cell deformab ility and by reducing the oxidation susceptibility of PUFA.