Abstract

In this study, gas chromatography-mass spectrometry (GC/MS) was used to analyse the isolated caffeine from kolanut and deternine the acute and chronic toxicity of the extract and the isolated caffeine. In chronic toxicity test, rats were divided into five groups (10 rats per group). Each rat was administered with normal saline (control group), crude kolanut extract (11.9 mg/kg), isolated caffeine (7.5 mg/kg), synthetic caffeine (6 mg/kg) or (6 mg/kg) decaffeinated kolanut extract orally for 90 days. Biochemical assessment and body weight of the rats were determined. In acute test, the limit test dose of 2000 mg/kg was administered to the rat and observed for 48 h post treatment. This dose caused behavioural changes but did not cause mortality in the rats tested. The results of the chronic administration showed that caffeine significantly (P < 0.05) decreased body weight. Liver enzymes were significantly (P < 0.05) increase, total plasma protein levels, creatinine, bilirubin, very low density lipoprotein (VLDL), low density lipoprotein (LDL) and total serum cholesterol levels were also significantly (P < 0.05) higher. However, urea was significantly (P < 0.05) lower in the caffeine treated groups. The results of the GC-MS analysis showed that the isolated caffeine from kolanut extract contains 82.69% pure caffeine with 96% in quality. Our results showed that the kolanut extract is rich in high quality caffeine and chronic consumption of it is associated with significant toxic effects as shown by elevated biochemical parameters, and reduction in body weight.

Key words: Acute and chronic toxicity, kolanut extract, Cola nitida, caffeine, decaffeinated, caffeine extraction, gas chromatography-mass spectrometry (GC-MS), biochemical parameters.