Phytochemical Screening and In vitro Antimicrobial Activity of Four Cameroonian Medicinal Plant Extracts against Bacterial and Fungal Strains Involved in Skin Lesion Infections

Background: Infections are recurrent in the presence of external skin lesions and significantly complicate the healing process. Plant extracts are used in the management of these complications. Objective: This study was aimed to evaluate the phytochemical composition and the in vitro antimicrobial activity of crude extracts of four Cameroonian medicinal plants. Methods: Primary and secondary metabolites were sought and quantified in the different aqueous and hydroethanolic extracts of these different plants through colorimetric tests and spectrophotometric assays. Determination of the Minimum Inhibitory Concentration by Broth dilution methods were used to test the antimicrobial activity of different extracts of Musa paradisiaca, Ficus exasperata, Dacryodes edulis and Citrullus lanatus against five reference bacterial strains: Shigella flexneri, Pseudomonas aeroginosa; Staphylococcus aureus; Klebsiela pneumonia, Eschericha coli and three fungal isolates: Candida Albicans; Candida parapsilosis; Candida glabrata. Results: Alkaloids, polyphenols (flavonoids, coumarins, total tannins), carbohydrates and total proteins were present in the different plant extracts with varying levels from one plant to another and from one extract to another. However, the D. edulis extracts had the highest levels overall. All the extracts tested inhibited the visible growth of one of the bacterial or fungal strains used, with MIC values between 1.565 and 25 mg/mL for bacterial strains and equal to 25 mg/mL for fungal isolates. The MIC values obtained with the reference molecules were between 0.015 and 0.0625 µg/mL and 0.0765 and 0.306 µg/mL respectively for Ciprofloxacin and Fluconazole. Conclusion: This study indicates clear evidence supporting the traditional use of M. paradisiaca, F. exasperata, D. edulis and C. lanatus in treating skin and wound infections related to bacterial and fungal.