Cinnamic acid lowers blood pressure and reversesvascular endothelial dysfunction in rats

Abdul Jabbar Shah ^c,*, Hafiz Misbah-ud-Din Qamar ^a, Umme Salma ^a,b, Taous Khan ^a

^a Cardiovascular Research Group, Department of Pharmacy, COMSATS University Islamabad, Abbottabad Campus, University Road,Abbottabad-22060, KP, Pakistan

^b Department of Pharmacy, Sardar Bahadur Khan Women's University, Balochistan, Pakistan

^c Department of Pharmacy, COMSATS University Islamabad, Abbottabad Campus, Abbottabad, 22060, Pakistan

Cinnamic acid (CA) possesses important cardiovascular effects such as cardioprotective, antiatherogenic, anti-hyperlipidemic and antioxidant, which predicts its potential role in the treatment of hypertension. The study wasexecuted to investigate the antihypertensive potential of CA in Sprague Dawley (SD) rats followed by evaluation indiverse vascular preparations. Invasive blood pressure monitoring technique was used in normotensive and hyper-tensive rats, under anesthesia. Isolated aortic rings from rat and rabbit, Langendorrf's perfused isolated rabbit heart and guinea-pig right atria were used to probe the underlying mechanisms. The responses were recorded with pressure andforce transducers connected to PowerLab Data Acquisition System. Intravenous administration of CA induced arespective 54% and 38% fall in mean arterial pressure (MAP) in the hypertensive and normotensive rats, respectively. Inrat aortic rings, the CA exhibited muscarinic receptors-linked NO and indomethacin-sensitive endothelium-dependent (>50%) and calcium antagonistic and KATP-mediated endothelium-independent vasodilator effects. The CA showednegative inotropic and chronotropic effects in guinea-pig atrial strips. The CA suppressed force of ventricular contraction and heart rate while caused a 25% increase in coronary flow. This study supports the medicinal importance of CA as antihypertensive agent.