Inhibition of bacterial growth using false yam (Icacina oliviformis) extract as an additive in liquid soap

摘要

False yam (Icacina oliviformis) is a drought-resistant root crop found in Northern Ghana. Research confirms it to contain some levels of antimicrobial, antifungal, antidiarrheal, antioxidant, and antidiabetic activities. This study was carried out to determine the effectiveness of False yam extracts incorporated in liquid soap against selected microorganisms. Polar solvent (methanol, ethanol, and water) extracts from the leaves, tuber (root), peels (root bark), and seeds were diluted with liquid soap to give concentrations of 50 mg/mL, 25 mg/mL, and 12.5 mg/mL. Test organisms used were Staphylococcus aureus, Escherichia coli, and Vibrio species. The results revealed significant differences (P < 0.05) among the different solvents and concentrations of the plant materials used. The ethanol seed extract at a concentration of 50 mg/mL was most inhibitive on Vibrio species with an inhibition diameter of 13 mm. The methanol peel extract also had the greatest inhibition on Escherichia coli with average inhibition zone of 7 mm to 12.5 mm followed closely by the tuber with maximum inhibition zone of 9 mm. The leaf extract generally exhibited higher values of inhibition on Staphylococcus aureus with zone range of 10 mm to 15 mm. The highest activity occurred with an inhibition zone of 15 mm diameter. The tuber and peel extracts recorded the highest antibacterial activity. Staphylococcus aureus appeared to be the most susceptible organism and the methanol extracts exhibited a relatively high frequency of inhibition. Further research efforts should combine the tuber and peel extracts to determine the possible synergistic and/or antagonistic effect.