Comparative study of the bioactive compounds of olive products on cardioprotection from ischemia-reperfusion injury in mice with metabolic syndrome

Abstract Background/Introduction The main bioactive compounds of olive products, oleuropein (OL), hydroxytyrosol (HT), oleocanthal (OC) and oleanolic Acid (OA) exert multiple benefits in cardiovascular diseases. However, their potential cardioprotective effect after chronic administration at a nutritional dose has not been studied in metabolic syndrome (MS). Purpose We evaluated and compared possible cardioprotective effects of chronic oral treatment with OL, HT, OC and OA in a mouse model of diet-induced MS. Methods We initially explored if OL, HT, OC, OA exert cardioprotection against ischemia-reperfusion (I/R) injury after chronic administration in healthy animals. The nutritional dose was selected as the equivalent to the estimated daily phenolic intake in humans following the Mediterranean diet. C57Bl6 mice were randomized into 5 groups and treated daily for 6 weeks as followed: i) DMSO 5%, ii) OL (20.6 mg/kg), iii) HT (5.9 mg/kg), iv) OC (11.6 mg/kg), v) OA (17.4 mg/kg). All animals were then subjected to I/R (30/120 min) and infarct size (IS) was determined. In a second cohort, C57Bl6 mice were fed with western diet for 14 weeks to induce MS. At 8th week, mice were randomized into 6 groups: i) Normal Saline (NS), ii) OL, iii) HT, iv) DMSO 5%, v) OC, vi) OA and treated daily with the assigned compound/vehicle for the last 6 weeks. At baseline, 8th and 14th week, body weight, mean arterial blood pressure (MAP) and fasting glucose levels were evaluated. Blood samples were collected at baseline and 14th week for the determination of the lipid profile and the mice were subjected to IR (30/120 min). Results OL, OC and OA reduced IS in healthy animals (p