In Vitro Antibacterial Assessment of Six Medicinal Plants Traditionally Used In Wound Care in South Western Nigeria

Abstract

Proximity, reliability and age long dependence on traditional medicine for health care delivery together with antibacterial resistance and high cost of antimicrobial drugs call for the validation of the efficacies of the medicinal plants. The effects of six Nigerian medicinal plants, which include Aspilia africana (Pers. C.D. Adams), Asystasia gangetica (L.) T. Anderson, Celosia laxa Schumach & Thonn, Cissus quadrangularis (L), Emilia coccinea (Sims) G.Don and Melanthera scandens (Schumach & Thonn), were investigated. The plants were tested against five bacteria commonly implicated in wound infections using standard methods. The minimum inhibitory concentrations (MICs) of the extracts ranged from 0.625 to 20.00 mg/ml. Extract of A. africana showed the least MIC values against Escherichia coli and Klebsiella pneumoniae (Gram-negative). The MIC of the extracts of C. laxa ranged between 1.25 and 20.00 mg/ml, it was 20.00 mg/ml for both Enterococcus faecalis and Pseudomonas aeruginosa. Staphylococcus aureus was the most susceptible organism to all the extracts of C. laxa. The MICs of ethanolic extract of E. coccinea for P. aeruginosa and S. aureus were 20.00 and 10.00 mg/ml respectively. Antibacterial activity of the plants was in the following increasing order: C. laxa, M. scandens, C. quadrangularis, A. africana, A. gangetica and E. coccinea. Ethanolic extract was the most effective of all the three extracts followed by petroleum ether. Aqueous extract has the least overall activity on the isolates. The inhibition of the common bacteria associated with wound infection by the extract preparations from the plants justifies the claims of the traditional healers in the study area.