Phytochemical and Elemental Composition, Ameliorative Potential and Safety of Aqueous Extracts of Selected Medicinal Plants against Pyrexia, Inflammation and Pain
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Date
2025-10
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Kenyatta University
Abstract
Prunus africana and Melia azedarach are traditionally used in Kakamega County, Kenya, for the management of fever, pain, and inflammation. However, their efficacy and safety remain scientifically unverified. Establishing preliminary data on these plants is important to guide further research and inform their safe use. Hence, this study’s purpose was to assess the antipyretic, anti-inflammatory and antinociceptive activity and safety of Prunus africana and Melia azedarach of aqueous leaf extracts in animal models. Fresh leaves of both plants were processed into aqueous extracts. Antipyretic activity was tested using turpentine-induced fever, while anti-inflammatory and antinociceptive effects were assessed using the formalin model. For each study, the animals were split into six groups each comprising of six animals: positive, normal and negative controls and three experimental groups for extract doses of 50, 100 and 150 mg/kg body weight administered orally. Diclofenac (15 mg/kg) served as the positive control. Acute toxicity was examined at single doses of 450-2000 mg/kg for fourteen days, while sub-acute toxicity was assessed at 150–450 mg/kg for four weeks with hematological, biochemical, and organ weight analyses. Phytochemical and mineral composition of the extracts was also determined. Both extracts demonstrated antipyretic and antinociceptive effects at all tested doses. Melia azedarach exhibited anti-inflammatory activity across doses, whereas Prunus africana lacked activity at the highest dose (150 mg/kg). Acute and sub-acute exposure produced some dose-dependent changes in body weight, relative organ weights, and hematological and biochemical parameters, though no severe toxicity was observed at the tested levels. Phytochemical analysis revealed flavonoids, phenols, alkaloids, and amino acids, while trace element analysis identified thirteen minerals in concentrations below recommended daily allowances. This study provides preliminary pharmacological and toxicological evidence supporting the traditional use of Prunus africana and Melia azedarach in managing fever, pain, and inflammation. The extracts demonstrated biological activity, though acute and sub-acute studies produced physiological changes that warrant caution. The new knowledge contributed by this study is the first experimental demonstration of both efficacy and safety profiles of aqueous leaf extracts of these plants in animal models, alongside identification of their phytochemical and mineral constituents. These findings support further mechanistic and long-term studies, including clinical evaluation, before safe therapeutic use in humans can be confirmed.
Description
A Thesis Submitted in Partial Fulfilment of the Requirements for the Award of the Degree of Master of Science (Biotechnology) in the School of Pure and Applied Sciences of Kenyatta University, October 2025.
Supervisors
1. Prof Eliud NM Njagi
2. Prof Mathew P Ngugi