Determining Cardiometabolic and Antioxidant Effects of Olive Leaf Extract in Patients with Essential Hypertension

Background Hypertension is one of the most common clinical disorders affecting millions worldwide. Some studies have indicated the role of oxidative stress in the pathogenesis of hypertension and the importance of antioxidant compounds in their control. Objective The aim of this study was to evaluate the effects of olive leaf extract (OLE), Olea europaea L., on cardiometabolic parameters and biomarkers of oxidative stress in patients with essential hypertension. Methods This randomized double-blind placebo-controlled clinical trial conducted in 2017 on 60 patients with essential hypertension aged 30-60 years referred to the cardiovascular clinic of Bu-Ali Sina Hospital in Qazvin, Iran. The patients were randomly allocated into two groups of OLE (n=30; receiving OLE 250 mg capsules twice per day for 12 weeks) and placebo (n=30, receiving placebo drug for 12 weeks). Before and after intervention, cardiometabolic parameters and oxidative stress biomarkers were measured using appropriate laboratory methods. To compare variables and groups, paired-t test and independent t-test were used, respectively. Findings The OLE intake led to a significant decrease in systolic blood pressure, serum total cholesterol, and malondialdehyde levels in hypertensive patients compared to the placebo group, but significantly increased superoxide dismutase activity (P<0.05). Moreover, the OLE intake had no significant effect on diastolic blood pressure, other lipid profiles and biomarkers of oxidative stress (P>0.05).  Conclusion OLE intake for 12 weeks had beneficial effects on some types of cardiometabolic and oxidative stress biomarkers in hypertensive patients.