Evaluation of antimicrobial and antioxidant properties of some herbs used in sub-Saharan Africa, Nigeria

Objective: To examine antimicrobial and antioxidant potentials of Cissus populnea (C. populnea) root and Securidaca longipedunculata (S. longipedunculata) leaf and root extracts using aqueous, ethanol and petroleum-ether media. Methods: The free radical 2,2-diphenyl-1-picrylhydrazyl was used to measure scavenging activities of extracts, while phenol and flavonoid contents were estimated by spectrophotometry and the antibacterial screening of extracts was done using disc diffusion method. The extracts were tested against five strains of Gram positive and negative bacteria. Minimum inhibitory concentration of extracts in the screening assay was according to micro-broth dilution, and minimum bactericidal concentration was carried out by agar diffusion method. Results: The ethanol extract of the S. longipedunculata leaf recorded the highest [(83.00 ± 2.97) μg/mL] radical scavenging potential while the least value [(48.50 ± 2.55) μg/mL] was recorded for C. populnea root ethanol extract. The highest phenol content was found in the ethanol extract of C. populnea [(145.60 ± 0.85) mg gallic acid equivalent/g], while the least value [(87.75 ± 3.46) mg gallic acid equivalent/g] was recorded in petroleum ether extract of S. longipedunculata. The highest and lowest values [(81.30 ± 0.99) and (46.60 ± 1.98) mg rutin equivalent/g] of flavonoid were recorded with ethanol extracts of S. longipedunculata leaf and root, respectively. The aqueous and ethanol leaf and root extracts of S. longipedunculata were active against the growth of Escherichia coli, Staphylococcus aureus, Vibrio cholerae, Pseudomonas aeruginosa and Salmonella typhi. Similar results were observed with ethanol and aqueous root extracts of C. populnea for the same bacteria. Conclusions: All the crude plant extracts possessed strong antioxidant and antimicrobial activities qualifying them as medicinal herbs that could be included in animal feed production.