Trans-cinnamaldehyde promotes nitric oxide release via the protein kinase-B/v-Akt murine thymoma viral oncogene -endothelial nitric oxide synthase pathway to alleviate hypertension in SHR. Cg-Leprcp/NDmcr rats

Beneficial effects of cinnamon and its extracts in the management of cardiovascular diseases and diabetes

Cardiovascular diseases (CVDs) and diabetes are the leading causes of death worldwide, which underlines the urgent necessity to develop new pharmacotherapies. Cinnamon has been an eminent component of spice and traditional Chinese medicine for thousands of years. Numerous lines of findings have elucidated that cinnamon has beneficial effects against CVDs in various ways, including endothelium protection, regulation of immune response, lowering blood lipids, antioxidative properties, anti-inflammatory properties, suppression of vascular smooth muscle cell (VSMC) growth and mobilization, repression of platelet activity and thrombosis and inhibition of angiogenesis. Furthermore, emerging evidence has established that cinnamon improves diabetes, a crucial risk factor for CVDs, by enhancing insulin sensitivity and insulin secretion; regulating the enzyme activity involved in glucose; regulating glucose metabolism in the liver, adipose tissue and muscle; ameliorating oxidative stress and inflammation to protect islet cells; and improving diabetes complications. In this review, we summarized the mechanisms by which cinnamon regulates CVDs and diabetes in order to provide a theoretical basis for the further clinical application of cinnamon.

The role of transient receptor potential ankyrin 1 in age-related endothelial dysfunction

Oxidative stress plays a key role in age-related vascular disease. The present study aimed to investigate the role of an antioxidant channel, transient receptor potential ankyrin 1 (TRPA1), in age-related endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) were grown to induce replicative senescence, and 6-month-old young, 12-month-old middle-aged, and 24-month-old aged mice were used. TRPA1 was downregulated in senescent HUVECs, so were endothelial nitric oxide synthase (eNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), and uncoupling protein 2 (UCP2). Activating TRPA1 with cinnamaldehyde prevented downregulation of eNOS, Nrf2, and UCP2, inhibited superoxide production and apoptosis, and preserved nitric oxide bioavailability in senescent HUVECs. TRPA1, phosphorylated eNOS, Nrf2 and UCP2 were significantly downregulated in aged aortas compared with young aortas after a compensatory upregulation in middle-aged aortas. Dietary administration of cinnamaldehyde for 12 months prevented mitochondrial dysfunction, improved endothelium-dependent relaxation, and increased expression of eNOS, Nrf2, and UCP2 in aged aortas. Importantly, the effects of cinnamaldehyde can be blocked by a TRPA1 antagonist HC-030031. These findings suggest that TRPA1 may play a critical role in age-related endothelial dysfunction and may become a therapeutic target for the treatment and prevention of age-related vascular disease.

Combinatorial effects of trans-cinnamaldehyde with fluoride and chlorhexidine on Streptococcus mutans

AIMS

The aim of this study was to investigate the effects of trans-cinnamaldehyde (TC) and its synergistic activity with chlorhexidine (CHX) and fluoride against Streptococcus mutans.

METHODS AND RESULTS

Streptococcus mutans UA159 was treated with TC alone and in combination with CHX or sodium fluoride. The synergy profile was analysed using the Zero Interaction Potency model. TC showed strong synergism (synergy score of 21·697) with CHX, but additive effect (synergy score of 5·298) with fluoride. TC and the combinations were tested for acid production (glycolytic pH drop) and biofilm formation by S. mutans, and nitric oxide production in macrophages. TC significantly inhibited sucrose-dependent biofilm formation and acid production by S. mutans. Mechanistic studies were carried out by qRT-PCR-based transcriptomic studies which showed that TC acts by impairing genes related to metabolism, quorum sensing, bacteriocin expression, stress tolerance and biofilm formation.

CONCLUSIONS

trans-Cinnamaldehyde potentiates CHX and sodium fluoride in inhibiting S. mutans biofilms and virulence through multiple mechanisms. This study sheds significant new light on the potential to develop TC as an anti-caries treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Oral diseases were classified as a 'silent epidemic' in the US Surgeon General's Report on Oral Health. Two decades later, >4 billion people are still affected worldwide by caries, having significant effects on the quality of life. There is an urgent need to develop novel compounds and strategies to combat dental caries. Here, we prove that TC downregulates multiple pathways and potentiates the CHX and fluoride to prevent S. mutans biofilms and virulence. This study sheds significant new light on the potential to develop TC in combination with CHX or fluoride as novel treatments to arrest dental caries.