ABSTRACT
This study aimed to investigate the anti-hypertensive potential of crude leaf extracts of Pterocarpus indicus (Narra). Hypertension was induced using Epinephrine HCI, 15-20 ug/kg body weight IV in 6 male cats, followed by an administration of Narra leaf extracts with a concentration of 0.25 g/kg BW IV at the peak of the epinephrines hypertensive effect. To test for the possible dose-response effect, the procedure was repeated using 0.5 and 1 g/kg BW IV Narra extracts. The systolic, diastolic and mean arterial blood pressures, pulse pressure, respiratory rate (SBP, OBP, MABP, PP and RR, respectively), respiratory and ECG (Q-R interval) amplitude, and the time for the Narra extract to effect were monitored using GrassO polygraph. Analysis of the data using General Linear Model (GLM) Repeated Measures showed that crude Narra leaf extracts at 0.25, 0.5 and 1 g/kg BW significantly lowered an epinephrine-induced rise in SBP (p=0.001), MABP (p=0.001), PP (p=0.0001) and ECG (Q-R interval) amplitude (p=0.05). However, there was no observed effect on the DBP (p=0.698), HR (p=0.9), RR (p=0.846) and respiratory amplitude (p=0.762). Moreover, no dose-response relationship was observed among the 3 doses of the narra extract on all physiologic parameters mentioned. Also, none of the doses was able to return the MABP to baseline (p=0.053). The observed decline in the SBP may have probably been due to the resultant decrease in the amplitude or force of contraction of the heart. Concomitantly, this may cause a decrease in the anti-hypertensive effect. (Author)