Evaluation of in vitro and in vivo antimicrobial efficacy of non-alcohol-based herbal hand scrubs developed against selected pathogens
Shanika Karunanayaka, Sujeewa Hettihewa*, Dharshan Silva, Lilani Karunanayake

Abstract: Handwashing with water and soap limits the transmission of respiratory diseases, but considered as time spending method. The aim of this study was to formulate non-alcohol-based herbal hand scrubs (NABHHS) and to evaluate the antimicrobial efficacy against selected pathogens. Six types of hand scrubs (NAF1-NAF6) were formulated by incorporating essential oils and the physical stability was studied for three months at room temperature. Agar well diffusion method was performed to evaluate in vitro antimicrobial efficacy of the formulations developed against selected standard cultures and clinical isolates of pathogens compared with positive and negative controls. The most active and stable formulations (NAF1 and NAF3) were selected and subjected for the in vivo (phase II) efficacy test to evaluate the clinically proven safety, and skin compatibility. The formulations were found to be homogenous, liquid, and milky white colour with a pleasant odor. Among the mean values of zone inhibition for NAF1, high values were obtained as 17.33±1.15, 25.33±0.58, 23.00±5.29, and 18.67±1.53 mm against Proteus mirabilis, Candida albicans, Streptococcus pyogenes, and Staphylococcus aureus respectively. Among the mean values of inhibition zones of NAF3, high values were obtained as 23.33±1.15, 20.33±1.15, 34.67±1.15, and 21.00±0.00 mm against Acinetobacter baumannii, Salmonella Typhi, Candida albicans, and Streptococcus pyogenes respectively. Zero values of inhibition were obtained for distilled water (negative control) while the market product (positive control) showed the zones of inhibition of 8.00-12.15 mm against Enterobacter cloacae, Salmonella Typhi, Candida albicans, Streptococcus pyogenesEnterococcus faecium, and Staphylococcus aureus. In conclusion, the NABHHSs developed in this study have promising in vitro antimicrobial activity against the tested pathogens and clinically proven safety, and skin compatibility against healthy human volunteers. Moreover, promising antifungal activity was showed by both formulations NAF1 and NAF3 against Candida albicans.

Keywords: Antimicrobial efficacy; essential oil; hand scrubs; pathogens