BACKGROUND AND OBJECTIVE: Glycyrrhiza glabra rhizome extracts have been widely used in traditional medicine for the treatment of peptic ulcers and cough; therefore, evaluation of the side-effects of these extracts seems essential. In this study, we aimed to evaluate the effect of G. glabra rhizome extract on blood pressure and heart rate of male rats and assess its interaction with the nitrergic system.

METHODS: In this experimental study, 10 male rats intravenously received G. glabra extracts and LNAME drug in three different modes: 1) administration of the physiological serum at baseline, 2) concomitant administration of LNAME (5 mg/kg) and the physiological serum in the control mode, and 3) concomitant administration of G. glabra extract (90 mg/kg) and LNAME in the trial mode. Heart rate and blood pressure of the animals were measured after the administration of G. glabra extract and LNAME drug. The measurements were performed, using organ electrodes, an arterial catheter connected to a pressure transducer, and a PowerLab A-D device.

FINDINGS: Based on the findings, a significant decline was observed in the mean arterial pressure in the trial mode (93±8.04), compared to the control mode (129±2.7) (p≤0.05). In addition, a significant reduction was observed in the mean systolic blood pressure in the trial mode (98±7.9), compared to the control mode (136±2.9) (p<0.04). Moreover, a significant decline was observed in the mean diastolic blood pressure in the trial mode (377±3.04) in comparison with the control mode (423±2.7) (p<0.04).

CONCLUSION: According to the results of the present study, concomitant administration of G. glabra extract and LNAME drug caused a significant decline in blood pressure