RESEACH TITLE: Effect of polyphenols of olive oil, hydroxytyrosol and its glucuronides on the vascular reactivity in a type 2 diabetes context
CONDUCTED BY: Université d’Avignon, Lab Pharm-ecologie Cardiovasculaire, Avignon, France; AMU Université, Marseille, France; Universite d’Avignon, Avignon, France; Laboratoire IVERY, Marseille, France; Université Aix-Marseille, UMR NORT, Nutrition, Obésité et Risques thrombotiques, Marseille, France
PUBLISHED ON: Archives of Cardiovascular Diseases Supplements
Hydroxytyrosol and Resveratrol are recognized as strong antioxidant polyphenolic compound. While Resveratrol antioxidative mechanisms are well known, those of Hydroxytyrosol are controversial because of its low intestinal absorption and its high metabolisation in glucuronides (GC), suggesting that these metabolites are susceptible to express Hydroxytyrosol biologicial activity in vivo. Our objective was to compare the vasorelaxant effect of Res, Hydroxytyrosol and GC on isolated aortic from young males Wistar rats (3months), old Wistar and GK rats (14 months), in presence or not of t-BOOH-induced oxidative stress (1mM; 30min). No vasorelaxant effect of the polyphenols was observed in young or old males Wistar rats. However, in old GK rats, Res and GC had significant vasorelaxant effect. In response to t-BOOH-induced oxidative stress, Hydroxytyrosol and RES protected the aortic rings of young Wistar rats (p < 0.05). However, different maximal relaxation was found between HT +t-BOOH, Res +t-BOOH and Control (72.5±2.8%, 76.1%±7.7% vs 88.8±0.7% ; p<0.05). The sensibility to Ach (EC50) was altered negatively in Res +t-BOOH and t-BOOH in comparison of Control (2084.6±1687 nM, 2983.5±1110 nM vs 66.9±10.7 nM). The protective effect of Hydroxytyrosol and RES against the acute effect of t-BOOH-induced oxidative stress in a normal context tends to confirm our results in old GK rats, highlighting an effect of these polyphenols only in a pro-oxidant context.