Antitrypanosomial activities and cytotoxic effects of Garcinia kola (bitter kola) aqueous seed extract and Berenil in abino Wister rats

Abstract

Trypanosomiasis, otherwise known as (sleeping sickness) is a major disease of economic and public health importance caused by Trypanosoma brucei gambianse parasite that affects humans. In 2014, WHO stated that 300,000 cases were reported diagnosed and treated, while others died or live with disability based on the none- availability of novel drugs, high toxicity of exciting drugs and development of resistance to the available drugs by the parasite. Therefore the use of plant extract is fast becoming the choice method for the treatment of the disease. This study investigated trypanosomal activity and cytotoxicity of Garcinia kola aqueous seed extract and diminazene aceturate drug on the liver of typanosomiasis- infected albino Wister rat. The extract was obtained through maceration with distilled water and phytochemical analysis was performed using various standard methods. In vitro activity of the extract and diminazene aceturate was determined using rapid matching techniques at 3 hours post incubation with different doses of the extract and 3.5 mg/kg.bw of standard drug. In vivo study was carried out using sixty two (62) Wister rats divided into 10 groups. Group A (normal control), was non infected and non-treated but received 10 mL of distilled water; Groups (B-H), were infected by intraperitoneal inoculation of 1 mL of parasitized blood containing 1.0105/ml of T. brucei gambianse parasites, and treated with different doses of Garcinia kola seed extract (200, 400 – 1400 mg/kg.bw); Group I was: infected and treated with standard drug dose (Standard control); Group J was infected and untreated (Pathological control). The treatment lasted for 21 days at 3 days intervals. Biochemical analysis of the liver function was performed by colorimetric method. Histological analysis was carried out using standard tissue processing and staining with Haematoxilin and Eosin stains. Data were analyzed statistically using Anova Turkey’s post hoc SPSS version 2.0 software and at 0.01 significant difference. Results revealed the phytochemical components of the seed as flavonoids, steroids, tannin, saponin, anthraquinones, glycoside and carbohydrate. Various biochemical effects on the liver functions were observed in all the extract- treated and control groups. Garcinia kola seed extract exhibited trypanosostatic effect at doses <400 mg and trypanocidal activity at doses > 400 mg both in vitro and in vitro and in vivo, compared with trypanocidal activity of the standard drug at a dose of 3.5 mg/kg.bw. Garcinia kola seed extract proved to be highly toxic to the liver at high doses >200 mg /kg.bw due to various pathological lesions observed in the liver histology of the extract- treated groups when compared with standard drug which also produced similar organ toxicity effect at standard dose This result of the study shows that Garcinia kola aqueous seed extract may be used to design drug for the treatment of trypanosomiasis at lower concentrations and the use of Berenil in human treatment should be discontinued due to its high toxicity in animal model.