Protective effects of cinnamic acid and cinnamic aldehyde on isoproterenol-induced acute myocardial ischemia in rats

Abstract

Ethnopharmacological relevance

Cinnamomum cassia is a well-known traditional Chinese herb that is widely used for the treatment of ischemic heart disease (IHD). It has favorable effects, but its mechanism is not clear. To investigate the effects of cinnamic aldehyde (CA) and cinnamic acid (CD) isolated from Cinnamomum cassia against myocardial ischemia produced in rats by isoproterenol (ISO).

Materials and methods

Ninety male Sprague-Dawley rats were randomized equally to nine groups: a control group, an untreated model group, CA (22.5, 45, 90 mg/kg) or CD (37.5, 75, 150 mg/kg) treatment, or propranolol (30 mg/kg). Rats were treated for 14 days and then given ISO, 4 mg/kg for 2 consecutive days by subcutaneous injection. ST-segment elevation was measured after the last administration. Serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO), and blood rheology were measured after the rats were sacrificed. The hearts were excised for determining heart weight index, microscopic examination, superoxide dismutase (SOD) and malondialdehyde (MDA) measurements.

Results

CA and CD decreased the ST elevation induced by acute myocardial ischemia, decreased serum levels of CK-MB, LDH, TNF-α and IL-6, and increased serum NO activity. CA and CD increased SOD activity and decreased MDA content in myocardial tissue.

Conclusion

CA and CD were cardioprotective in a rat model of ischemic myocardial injury. The protection was attributable to anti-oxidative and anti-inflammatory properties, as well as increased NO. The results support further study of CA and CD as potential treatments for ischemic heart disease.

Introduction

Ischemic heart disease (IHD) is the leading cause of morbidity and mortality in the Western world; and, according to the World Health Organization, it will be the leading cause of death in the world (Lopez et al., 2006, Yang et al., 2013). Despite advances in basic research and clinical improvements, there have been no fundamental breakthroughs in drug treatment.

Cinnamomum cassia or Chinese cinnamon, is important not only as a spice but also for its antioxidant activity (Lin et al., 2003, Shan et al., 2005, Dugoua et al., 2007), which has potential therapeutic benefit in cardiovascular disease. Aqueous extracts of cinnamon and cinnamon oil have been reported to reduce injury to cardiac function and dynamic change in blood flow induced by isoproterenol (ISO) (Kubavat and Asdaq, 2009). Cinnamic aldehyde (CA) and its derivative cinnamic acid (CD) are the main chemical ingredients of Cinnamomum cassia, which has been reported to possess anti-oxidative (Foti et al., 2004, Lee et al., 2004) and anti-inflammatory properties (Zhang and Ji, 1992, Liao et al., 2012). The preconditioning effects of CA in ischemia/reperfusion injury have been demonstrated previously (Chen et al., 1990, Jiao et al., 2011). Overall, these findings depicted CA as a potential therapeutic agent in IHD. However, the possible protective mechanisms of CA and CD on myocardial ischemia are not fully understood. This study investigated the cardioprotective effects of CA and CD against acute ischemic myocardial injury in a rat model of ISO induced myocardial ischemia (Grimm et al., 1998, Li et al., 2012).