Blood Pressure Reducing Effect of Bitter Kola (<i>Garcinia kola</i>, Heckel) in Wistar Rats

Abstract

In this study the effect of Garcinia kola (GK) on blood pressure was investigated. Albino wistar rats were divided into three groups. Groups A rats had normal rat chow and water ad-libitum while groups B and C rats had Garcinia kola diet of 10% w/w and 15% w/w respectively, their blood pressures were monitored weekly for a period of 6 weeks. Secondly, inbred wistar rats weighing on the average 185g were anaestezized with thiopentone sodium 100mg/kg body weight (b.wt) intraperitoneally and prepared for injection and for blood pressure measurements on a recording device (Ugo Basile Itlay). Significant reduction in blood pressure (P<0.05) was observed in rats given GK-enriched diets, in the third week. During preliminary investigations it was observed that 5.0mg/kg b.wt dose of extract was lethal after 6 minutes, while 3.0mg/kg b.wt of the extract was tolerated for upwards of four hours. Based on these findings, graded doses of the extract. (0.5 – 3.0mg/kg) were used and these doses produced statistically significiant (P<0.05) fall in mean arterial pressure and also significant (P<0.05) increase in heart rate. Cholinergic blockade produced no significant attenuation on the effect of extract. However there was a significant (P<0.05) attenuation to extract effect after Histaminergic blockade. This study shows that Garcinia kola contains in its alcohol extract, a vasoactive substance that has a blood pressure reducing effect.

Keywords: blood pressure, Garcinia kola, Vasoactive, Heart rate