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

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 (CM), lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-alpha), 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-alpha 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. (C) 2013 Elsevier Ireland Ltd. All rights reserved.