Iridoid-loganic acid versus anthocyanins from the Cornus mas fruits (cornelian cherry): Common and different effects on diet-induced atherosclerosis, PPARs expression and inflammation

Abstract

Background and aims: Cardiovascular benefits of fruits are attributed mainly to their (poly)phenolic constituents, especially anthocyanins. The main aim of our study is to compare effects of iridoids and anthocyanins from one fruit on diet-induced atherosclerosis. The cornelian cherry is a native or cultivated plant that grows in many European countries, used in cuisine and folk medicine. In our previous study, we showed its constituents and proved that oral administration of lyophilized fruits to hypercholesterolemic rabbits had preventive effects on atherosclerosis through the activation of PPARα expression. In this study, we have compared the effects of the main constituents of the cornelian cherry:iridoid loganic acid and anthocyanins.

Methods: Our experiment followed the model used in our previous study, in which rabbits were fed 1% cholesterol.

Results: We showed that both loganic acid (20 mg/kg b.w.) and a mixture of anthocyanins (10 mg/kg b.w.) administered orally for 60 days had a positive impact on dyslipidemia caused by cholesterol-rich diet, although the effects of anthocyanins were more pronounced. Anthocyanins decreased total and LDL-cholesterol and triglycerides and increased HDL-cholesterol. Loganic acid showed similar effects, but only the triglycerides and HDL-cholesterol changes achieved statistical significance. Anthocyanins, and to a lesser extent loganic acid, significantly decreased intima thickness and intima/media ratio in the thoracic aorta. Both substances decrease ox-LDL in the plasma. Anthocyanins significantly increased expression of PPARγ and α in the liver. Loganic acid also increased their expression, but to a lesser extent. Conversely, loganic acid showed pronounced anti-inflammatory effects, decreasing TNF-α and IL-6 activity.

Conclusions: Our results imply that both substances have a positive effect on factors contributing to the development of diet-induced atherosclerosis. Our results also indicate the potential health benefits of fruits containing anthocyanins and iridoids, and support the idea of creating composed phytopharmaceuticals containing both groups of substances.

Keywords: Anthocyanins; Atherosclerosis; Cornelian cherry; Hypercholesterolemia; IL-6; Iridoids; Loganic acid; PPARα; PPARγ; TNFα.