Evaluation of key antimicrobial properties of Moringa oleifera in relation to its use as a hand-washing product

Moringa oleifera (M. oleifera) is a fast-growing, drought-resistant plant found throughout tropical and subtropical regions. A previous study found dry M. oleifera leaf powder to be similarly efficacious to non-medicated soap when used as a hand-wash, even without the use of water. These characteristics suggest that M. oleifera could serve as a potential hand-washing product in water and resource-limited contexts, such as humanitarian and emergency settings. The purpose of this study was to assess the efficacy of minimally processed M. oleifera sourced locally in Ghana as a hand-washing and antimicrobial product by assessing whether: (1) different preparations of M. oleifera have antibacterial properties against potential diarrheal pathogens through set-up of die-off studies; (2) M. oleifera is an effective hand-washing product by conducting an in-vivo trial with healthy volunteers; and (3) M. oleifera has antimicrobial properties in potentially reusable aqueous solutions, such as rinse water used for hand-washing. M. oleifera was found to be significantly less effective than non-medicated soap when tested as a hand-washing product and promoted the growth of bacteria in aqueous solution. Moreover, the Moringa used in the study was found to be host to pathogenic bacteria, reinforcing the idea that it is unsuitable to use as a hand-washing product. Accordingly, in its minimally processed form, M. oleifera appears to be an ineffective antimicrobial agent and its use as a hand-washing product in water-scarce and resource-limited settings is not recommended.