| dc.description.abstract | Introduction: Antimicrobial resistance to currently utilized drugs has caused major
challenges in both the agricultural and medical sectors in the past years. This resistance has
not only hampered the treatment of microbial diseases, but has also increased the cost of
treatment which is especially burdening third world countries. Therefore, there is need to find
alternative methods of curbing the infectious microorganisms.
Methodology: The current study was designed to evaluate the antimicrobial activity, toxicity
and phytochemical composition of organic and aqueous crude extracts from each plant were
were evaluated for their in vitro antimicrobial activity against methicillin resistant
Staphylococcus aureus (MRSA), Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa
and Candida albicans using broth dilution and disc diffusion methods. Toxicity was
determined using Brine-shrimp larvae assay while the presence of flavonoids, alkaloids,
saponins and sesquiterpene lactones was determined using Thin Layer Chromatography
(TLC). Analysis of variance (ANOVA) was used to analyse the disc diffusion results.
Finney’s computer programme was used to determine the LDC50 of each extract.
Results: It was observed that the organic crude extracts of all the tested plants except L.
cornuta showed activity against four micro-organisms and at concentrations lower than the
aqueous crude extracts. None of the crude extracts elicited any inhibition against E. coli.
Adansonia digitata and G. trichocarpa had LC50>1000 μg/ml and were shown to be nontoxic
to Brine shrimp larvae unlike those of Z. chalybeum and L. cornuta which both had
LC50<500 ug/ml and were considered to be toxic. Phytochemical screening of the crude
extracts showed that alkaloids, flavonoids, sesquiterpene lactones and saponins were present
in the four plants under investigation.
Conclusion: This study provides the first record of antimicrobial activity, toxicity and
phytochemical composition of G. trichocarpa. The study has shown that A. digitata and Z.
chalybeum possess promising antimicrobial activity against microbes of health importance
and could lead to the isolation of new and effective antimicrobial compounds. Further
research should be carried on Z. chalybeum and A. digitata to isolate and characterize the
compounds responsible for the observed activity. | en_US |
