Cinnamaldehyde protects from methylglyoxal-induced vascular damage: Effect on nitric oxide and advanced glycation end products.

Abstract

The protective effect and mechanism(s) of action of cinnamaldehyde on the highly reactive secondary sugar derivative, methylglyoxal, induced vascular damage were investigated using isolated rat thoracic aorta. Aorta was incubated with methylglyoxal and cinnamaldehyde where vascular reactivity was assessed through phenylephrine- and acetylcholine-induced contraction and relaxation, respectively. Cinnamaldehyde's antioxidant activity, ability to induce aortic nitric oxide release, and effect on advanced glycation end products formation (AGEs) was also studied. Results showed that cinnamaldehyde significantly alleviated the exaggerated contraction and improved the attenuated dilation of the aorta secondary to incubation with methylglyoxal. Furthermore, cinnamaldehyde stimulated aortic nitric oxide production from isolated aorta giving levels similar to acetylcholine and significantly reduced both methylglyoxal-induced AGEs and protein oxidation products formation. In conclusion, cinnamaldehyde protects from methyglyoxal-induced vascular damage mainly by improving the vasodilation in addition to endothelial nitric oxide production and reducing the detrimental AGE-inflicted vascular damage. PRACTICAL APPLICATIONS: The use of naturally occurring products to alleviate various disease-related complications is highly attractive due to their easy availability, relatively affordable prices compared to pharmaceutical products, and their favorable safety profile. In the case of cinnamaldehyde, its excessive and highly reputable consumption in the food industry facilitates promoting a daily intake of the natural compound with the purpose of counteracting the destructive effect that elevated blood glucose has on vascular function. According to findings obtained from this study, frequent cinnamaldehyde intake will improve vascular reactivity by acting on vasodilatory mechanisms and inhibiting glycation reactions, hence improving the hyperglycemia associated hypertensive state. The study also paves the way for future research to determine the clinical efficacy of cinnamaldehyde having established its competence in protecting vascular function in a lab setting.