The effect of honey and surfactant type on the antibacterial properties of the leaf essential oil of Ocimum gratissimum Linn. against common wound-infecting organisms

Abstract

Summary Honey is reported to have wound healing properties. This study aimed at investigating its effect as well as those of surfactants on the antibacterial activity of the essential oil of Ocimum gratissimum L. (ocimum oil). The antibacterial activity of dispersions of ocimum oil (2%) in methanol, honey, a macrogol blend, nonionic and ionic emulsifiers were assessed by cup–plate method using type bacteria and wound isolates. Honey enhanced the antibacterial activity of ocimum oil to a greater extent than the macrogol blend. The activity of ocimum oil emulsion in cetrimide (cationic) was lower than obtained for cetrimide solution. Emulsion of the oil in sodium lauryl sulphate (anionic) exhibited a slightly higher activity than the solution of the surfactant alone. Although Tween® 20 (nonionic) and aqueous methanol had no activity, the emulsion of the oil in Tween® 20 showed lesser activity than the oil solution in methanol. Honey’s inherent antibacterial activity, surfactant charge interaction and the effect of emulsification were adduced to the observed differences in antibacterial activity of the ocimum oil formulations. Our findings indicated honey as a suitable base for ocimum oil especially in the treatment of infected wounds. Caution is, however, desirable in the use of surfactants with ocimum oil.