O8 Study on antihypertensive activity of an aqueous extract of Anogeissus leiocarpus (AEAL) DC Guill et Perr bark of trunk in L-NAME-induced hypertensive rats

Background The present study investigates the effect of AEAL on normotensive Wistar rats and its chronic antihypertensive effects in L-NAME-induced hypertensive rats by using a non-invasive tail-cuff model. Methods The effects of AEAL (50 mg/kg) and NaCl 0.9% on blood pressure were investigated by daily oral administration in normotensive Wistar rats over four weeks. L-NAME-induced hypertensive rats were produced by L-NAME (40 mg/kg) daily oral administration for two weeks. For chronic antihypertensive effects, animals were treated with L-NAME for two weeks and then, L-NAME was administrated in combination with AEAL (10 or 50 mg/kg/day) and compared with a control group receiving only NaCl 0.9% for two following weeks. The blood pressure was measured daily by a Blood Pressure Recorder system. Results In normotensive rats, daily administration of AEAL (50 mg/kg) had no significant effect on their blood pressure, which was similar to that of the control group. Daily oral administration of L-NAME induced a progressive increase in systolic blood pressure (SBP) from 115.8 ± 7.9 mmHg to 153.5 ± 4.6 mmHg after two weeks of treatment, which was maintained to the end of the treatment. In L-NAME-induced hypertensive rats, AEAL (50 mg/kg) significantly decreased SPB from 160.0 ± 5.8 mmHg to 108.8 ± 2.7 mmHg after only four days of administration. In addition, the lower dose of AEAL (10 mg/kg) also normalized the SBP of L-NAME-induced hypertensive rats, however this was only evident after eight days of administration. Conclusion These findings suggest that AEAL affords significant antihypertensive effects against L-NAME-induced hypertensive rats.