Antimicrobial and phytochemical evaluation of the leaf, stem bark and root extracts of Cyathula prostrata (L) Blume against some human pathogens

Gideon Ikechukwu Ogu, Williams Omotola Tanimowo, Perpetua Ugonna Nwachukwu, Bright Esegbuyota Igere

Abstract
The antimicrobial activities of aqueous (cold and hot) and ethanolic extracts of leaf stem bark and root of Cyathula prostrata were investigated against some human clinical isolates of Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Salmonella typhi, and Candida albicans using the Agar well diffusion method at extract concentration of 25mg/ml. Ciprofloxacin(5μg/ml) and Fluconazole (20μg/ml) drugs was used as positive reference standards to determine the sensitivity of the strains. Results obtained showed that all the test isolates were inhibited by various fractions of the leaf, root and stem bark extracts. The antimicrobial activities of the different plant parts were not significantly different (P<0.05), though the greatest activities were observed with the ethanolic fractions (14.0-25.5 mm), followed by the hot water (12.0-24.2 mm) and cold extracts (13.0-18.5 mm). An inhibition range of 24.0-25.5mm and 28.5mm were observed from ciprofloxacin and fluconazole drugs respectively. The percentage susceptibility of the most sensitive bacterial isolate (E. coli,) was 95.9% while the least (K. pneumoniae) had 40.0% sensitivity. Candida albicans had a percentage susceptibility of 57.5%. The minimum inhibitory concentration (MIC) ranged between 400 and 800μg/ml. The observed phytochemical compounds were saponins, tannins, flavonoids, alkaloids, cardiac glycosides and steroids. This study has justified the applications of Cyathula prostrata in the traditional herbal medicines and therefore holds a promise as a potential source of novel broad spectrum drug for treating infectious diseases.

Key words: Cyathula prostrata, aqueous extract, ethanol extract, antimicrobial activity