Evaluation of antibacterial effects of Aloe vera extracts against Vibrio cholerae and Listeria monocytogenes

The aim of the present study was to evaluate the antimicrobial effects of aqueous, ethanol, methanol, acetone, chloroform and ethyl acetate extracts of Aloe vera leaves on two fish infectious bacteria, Vibrio cholerae and Listeria monocytogenes. The Aloe vera extracts obtained through rotary apparatus and V. cholerae and L. monocytogenes provided from Iranian fungi and bacterial collection. Minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) of the extracts were determined using dilution in well method. Moreover, the diameters of inhibition zones was determined through disk diffusion method. Results of this study showed while aqueous extract of Aloe vera had inhibitory and lethal effects on L. monocytogenes, but have no influence on V. cholerae. The most inhibitory and lethal characteristics of studied extracts on both bacteria was due to chloroform solvent, while had more influence on L. monocytogenes. Chloroform extract tend its inhibitory property even in the most diluted form. Like inhibitory properties, the biggest diameters of inhibition zones was from chloroform extract against L. monocytogenes. Acording to edibility of Aloe vera, its availability and reasonable value, it is possible to use Aloe vera as an alternative for conventional antibiotics and chemical disinfectants in aquaculture rearing pools.