Evaluation of Selected Medicinal Plants for Chemotherapeutic Activities on Plasmodium Knowlesi and Plasmodium Berghei

Were, Patrick Simiyu (2010) Evaluation of Selected Medicinal Plants for Chemotherapeutic Activities on Plasmodium Knowlesi and Plasmodium Berghei. Masters thesis, Kenyatta University.

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Malaria is one of the most widespread haemoparasitic diseases in the world, with an estimated incidence of about 500 million clinical cases annually and a corresponding annual mortality of up to 2.7 million. The use of conventional antimalarial drugs as a control strategy for malaria is greatly hampered by drug resistance exhibited by the parasites. Moreover, about 75% of the population in Africa does not have access to conventional medicine and therefore resort to traditional medicine (TM) for treating the disease. These TM suffer from lack of objective diagnosis and paucity of information on pharrnacokinetic factors such as formulation, toxicity, dosage forms and efficacy. Among the Kenyan communities living around Ngong Division of Kajiado District, malaria is a common problem and has been culturally treated using TM. This study was therefore carried out to determine the efficacy of four selected medicinal plants from Oloolua Forest, Ngong Division, popularly used by local herbalists in treating malaria. A total of 15 crude extracts were prepared from Warburgia ugandensis, Zanthoxylum usambarense, Aloe ngongensis and Ajuga remota and assayed for in vitro activities against Plasmodium berghei and P. knowlesi. Extracts that displayed high activities were subsequently assayed for curative and prophylactic activities against P. berghei using the four-day suppressive test in BALB/c mice. A total of 40 male adult mice were used in the two regimens in which experimental mice were treated with each extract at a dose rate of 200mg/kg/day being administered intraperitoneally, while control groups received Phosphate-Buffered Saline at the same rate. Mean parasitaemia inhibitions and survivorship values were reported as means ± SEM and compared using one-way analysis of variance (ANOVA) and the student t-test. All p-values less than 0.05 were considered statistically significant. Significant reductions in parasitaemia levels from in vitro tests (4 = 19.84,p < 0.05) were observed in treated groups relative to the controls. Three extracts; chloroformic and methanolic from W ugandensis and aqueous extraction of Z usambarense displayed significantly high parasitaemia suppression in chemotherapeutic (F = 9.63, df = 3, 15,P < 0.05) and chemoprophylactic (F = 5.812, df = 3, 15, P < 0.05) assays respectively. The most effective chemotherapeutic agent was the chloroformic extract with an average parasitaemia suppression of 69%. On the other hand, the most active prophylactic agent was found to be an aqueous extract from W ugandensis that produced 67% suppression of parasites in BALB/c mice. The same extract was equally therapeutic, giving a suppressive value of 65%. In terms of mice survivorship, the aqueous extract from Z usambarense as well as both methanolic and chioroformic extracts from W ugandensis significantly increased mean survival times (MST) in treated groups in both therapeutic (F = 40.462, df= 3, 10,p < 0.000) and prophylactic analyses (F = 67.74, df= 3, 10, p < 0.000). The results indicate that W ugandensis and Z usambarense possess bioactive antiplasmodial compounds. On the basis of this study, it is recommended that bioactive substances from W ugandensis and Z usambarense should be identified and characterized as prime candidates for novel antimalarial drugs.

Item Type: Thesis (Masters)
Subjects: Q Science > QL Zoology
Q Science > QR Microbiology
Divisions: Africana
Depositing User: Tim Khabala
Date Deposited: 12 Sep 2017 12:06
Last Modified: 12 Sep 2017 12:06
URI: http://thesisbank.jhia.ac.ke/id/eprint/2188

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