Ethnobotanical Survey, Phytochemical Screening and Antimicrobial Analyses of Selected Medicinal Plants Used in Traditional Medicine in Kieni, Kiambu County, Kenya
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Date
2025-07
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Kenyatta University
Abstract
Therapeutic plants usage has become prevalent in the prevention and treatment of human ailments. Nevertheless, scientific data to validate the effectiveness of some plant species is limited. This study sought to identify and provide a record of therapeutic plants used in Kieni, Kiambu County, and subsequently, investigate their phytochemical and antimicrobial properties. To this end, questionnaires were administered using snow ball technique to identify the plant species used as remedy for human ailments. Five medicinal plants were selected for phytochemical and antimicrobial testing. Methanol was used as the extracting agent. Phytochemical testing was carried out using standard procedures while antimicrobial assay was done using disc diffusion method. A comprehensive list of twenty-eight medicinal plants distribute across 25 plant families were identified as remedy for common diseases for instance, malaria, skin infections, respiratory diseases and stomach problems. The study identified that the knowledge of therapeutic species was mainly obtained from immediate family members, specifically parents and grandparents (63%). The leaves (27%) were identified to be the most utilized plant part while the seeds (2%) were the least used. Qualitative analysis of methanol plant extracts of Cordia africana, Croton macrostachyus, Elaeodendron buchananii, Coleus barbatus and Senna didymobotrya showed that flavonoids, terpenoids and tannins were the most common phytochemicals found in all the extracts. Antimicrobial susceptibility testing, employing the disc diffusion method demonstrated Elaeodendron buchananii as the most effective against the tested micro-organisms while the least effective plants were Croton macrostachyus and Cordia africana. The methanol plant extracts showed limited effectiveness against Salmonella typhi and Escherichia coli. Nonetheless, it was observed that S. typhi displayed susceptibility to the leaves extracts of E. buchananii, exhibiting an average zone of inhibition measuring 12.000 mm. However, the tested plant species showed no potential to restrict the growth of Candida albicans. Minimum Inhibitory Concentration (MIC) using Broth dilution method was determined for plants that showed a region of inhibition of ≥ 9.00 mm. The most susceptible microorganisms were Streptococcus aureus with average zones of inhibition of 9.52 mm followed by Streptococcus pyogenes 9.14 mm and Bacillus subtilis 7.96 mm. The results of this study indicate that the community was able to identify medicinal plants, and that the identified plants have antimicrobial properties against the tested microbes. This study recommends further research on medicinal plants identified with the aim of discovering novel drugs for the treatment of bacterial infections.
Description
A Thesis Submitted in Partial Fulfillment of the Requirements for the Award of the Degree of Master of Science (Ethnobotany) in the School of Pure and Applied Sciences of Kenyatta University, July 2025.
Supervisor
1. Prof. Grace Gatheri
2. Dr. John Maingi