Effect of Garcinia Kola (Heckel) on Pharmacokinetic Parameters of Rifampicin

Abstract

Most herbal products are used with prescription drugs and have been found to affect the pharmacokinetics of these prescription 
drugs. The effect of concurrent administration of Garcinia kola on the pharmacokinetic parameters and penetration profile of 
rifampicin into the lung tissues were investigated using animal model. Albino rats in group A received rifampicin 10 mg/kg alone 
orally; Group B and C received 100 mg/kg and 200 mg/kg of Garcinia kola extract respectively for 10 days and on day 11, rifampicin 
10 mg/kg was given. Blood samples were withdrawn from each group at 0.5, 1, 2, 4, 8, 12 and 24 h time intervals respectively.
Blood samples were also withdrawn from the lungs in each group after 24 h and assayed to determine the concentration of rifampicin
in the lungs. Both 100 and 200 mg/kg of Garcinia kola showed reduction in the maximum concentration (Cmax), area under 
concentration (AUC), clearance time (ClT), and time for plasma concentration to decrease by half (t1/2) of rifampicin. Garcinia kola
significantly (P = 0.01) decreased concentration of rifampicin in the lungs by 32% and 39 % respectively. Our results show that the 
co-administration of Garcinia kola and rifampicin impairs the bioavailability of rifampicin and its penetration into the lungs.