Report: In vitro antimicrobial activities of extracts of Carpolobia lutea root

Several plants are used in folk medicine to treat infections. Carpolobia lutea, G.Don (Polygalaceae) is a medicinal plant commonly used by herbalists in Southern Nigeria against dental and genitourinary infections. The study was to evaluate the in vitro antimicrobial activities of n-hexane, chloroform, ethyl acetate and methanol extracts of Carpolobia lutea root. Four typed cultures of bacteria namely, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and two clinical strains of fungi, namely Candida albicans and Tinea capitis were analyzed using agar well diffusion method. The extracts that showed antimicrobial activity were then tested to determine the Minimum Inhibitory Concentration for each bacterial or fungal sample.The ethyl acetate extract gave the widest zone of inhibition (21.0 mm) followed by chloroform when tested on E. coli. No inhibition was observed with E.Coli. None of the extracts showed any inhibitory effect against Pseudomonas aeruginosa and the fungal strains of Candida albicans and Tinea capitis. The most potent of these extracts was Chloroform extract with Minimum Inhibitory Concentration (MIC) of 25 mg/ml for bacteria. The phytochemical screening of the root of C. lutea revealed the presence of saponins, anthraquinones, flavonoids, cardiac glycosides, simple sugar and terpenes.