Antimicrobial properties of Cnestis ferruginea Vahl ex DC

Scientific research into developing new antimicrobials from plants continues to be an interesting area for many scientists. This is because the resistance of microorganisms to anti-infective agents has affected a wide range of conditions, some of which are life-threatening. This study aimed to investigate the antimicrobial properties of Cnestis ferruginea (CF). Powdered roots of Cnestis ferruginea were extracted with petroleum ether (CFP), ethyl acetate (CFE) and methanol (CFM). The antimicrobial and microbial resistance modifying activity profiles of the extracts were studied against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 4853, Staphylococcus aureus ATCC 25923, clinical strains of Methicillin-Resistant Staphylococcus aureus, Streptococcus pyogenes, Klebsiella pneumonia, Staphylococcus epidermidis, Proteus mirabilis and Candida albicans. CFP and CFE showed no activity against the test organisms. CFM had mean zones of growth inhibition in the range of 11.0 ± 0.5 to 22.17 ± 0.24 mm against the test organisms. The MIC of CFM was within the range of 0.31 and 5.0 mg/mL, with MBC/MFC range of 2.5-20.0 mg/mL. The time-kill kinetics studies showed CFM is a static agent. At sub-inhibitory concentrations, CFM was able to increase the susceptibility of the test organisms to standard antibiotics from the range of 1-8 folds. CFM reduced the formation of biofilms from 100% to 56.59%, 62.33%, 65.89% and 71.88% against K. pneumonia, S. aureus, E. coli and P. aeruginosa, respectively. The findings of this study show that C. ferruginea possesses antimicrobial activity and therefore gives credence to its folkloric use.