Abstract

The rapidly emerging rate of antibiotic resistance requires alternative solutions rather than new drugs. Aloe has been used for medical applications and exhibits antimicrobial activity as well as immunomodulation effects. Use of the aloe peel has not been considered, even though it may harbor many useful compounds. In this study, the antimicrobial activity of Aloe vera peel extract in distilled water against Staphylococcus aureus, Bacillus spp.,Enterococcus spp., Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, and Vibrio spp. was ascertained. The number of bacterial colonies were significantly reduced by the application of peel extracts (P<0.05). The antimicrobial activity was especially strong against E. coli and Vibrio spp. (P<0.001). In vivo antimicrobial activity and immunomodulation effects were tested in mice challenged with S. typhimurium DT104. Fecal shedding of S. typhimurium DT104 significantly decreased and intestinal Salmonella specific IgA and IgG titers significantly increased in mice fed with peel extracts. In splenocyte cultures stimulated by concanavalin A, the extract did not affect the production of interleukin IL-2 and interferon-gamma but did promote the production of IL-4 and IL-10. The in vitro and in vivo antimicrobial activities and immunomodulatory properties of A. vera peel extract may be of commercial value.

Key words: Aloe vera, antimicrobial effect, immunomodulatory effect.