Phytochemical analysis and antimicrobial activity of Phytolacca dodecandra, Cucumis aculeatus and Erythrina excelsa

Abstract

Three medicinal plants, Erythrina excelsa, Phytolacca dodecandra and Cucumis aculeatus, collected from Siaya and Migori District in Kenya, were screened for the presence of phytochemicals. These plants have diverse compounds including phenolics, terpenoids, anthraquinones, alkaloids and flavonoids, whereby the terpenoids were the most abundant. The antimicrobial activity of the hexane, dichloromethane, ethyl acetate, methanol and water extracts from the stem barks, root barks and the leaves of selected medicinal plants were assayed against eight microorganisms. In comparison with the standard antibiotics (chloramphenicol), the dichloromethane extract presented a high activity against Pseudomonas aeruginosa ATCC 27853 and a moderate activity on Salmonella typhi (Clinical isolate). The methanol extract presented significant activity against clinical fungal isolates, Microsporum gypseum and Trychophyton mentagrophytes. The hexane and ethyl acetate extract of Cucumis aculeatus leaves were active against P. aeruginosa ATCC 27853, whereas the dichloromethane extract of Erythrina excelsa had antibacterial activity against Staphylococcus aureus ATCC 25923. Hexane, dichloromethane and water extracts of Erythrina excelsa also showed activity against Pseudomonas aeruginosa ATCC 27853. These investigations shows that various extracts obtained from Erythrina excelsa, Phytolacca dodecandra and Cucumis aculeatus could be used in vitro to inhibit the growth of some important bacteria and fungi. The above results justify the reason why these medicinal plants have been and are being used to treat the fungal and bacterial infections by the Luo community.

Keywords: Phytochemicals, Erythrina excelsa, Phytolacca dodecandra, Cucumis aculeatus, antimicrobial properties