Evaluation of the antibacterial effects of aqueous and ethanolic extracts of Aloe Vera on pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Listeria monocytogenes)

This Research was to investigate the antibacterial effects of aqueous and ethanolic extracts of Aloe Vera on pathogenic bacteria such as Staphylococcus aureus (ATCC25923), Escherichia coli (ATCC25922), Listeria monocytogenes (ATCC33090) using disk diffusion and broth Microdilution methods. The results illustrated that gram-positive bacteria are more sensitive to ethanolic extract of Aloe Vera as compared with gram-negatives bacteria. This phenomenon is due to the structure and the strength of cell wall in gram-negative bacteria as well as the nature and active compounds of Aloe Vera. Ethanolic extract of Aloe Vera showed that the maximum antibacterial activity on Staphylococcus aureus and Listeria monocytogenes in whichthe minimum inhibitory concentration (MIC) was 0.132 and 0.625 mg/ml respectively. The maximum inhibition zone was observed on Staphylococcus aureus and Listeria monocytogenes with 12 and 8 mm respectively. On the other hand, aqueous extract of Aloe Vera did not show any antibacterial activity. It is supposed that antibacterial compounds such as Anthraquinone, Hydroxyanthra and Saponin had the most roles for antibacterial activity in ethanolic extract on Aloe Vera.