Blood Pressure Reducing Effect of Bitter Kola (Garcinia kola, 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.