Comparative Study of the Antimicrobial Properties of Aloe Vera Juice and Gel (leaf) Extracts against Selected Clinical Isolates

The comparative study of the antimicrobial properties of Aloe vera juice and gel (leaf) extracts against selected clinical isolates have been investigated using standard microbiological methods. The organisms were Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Bacillus subtilis, Candida albicans and Aspergillus niger. The different extracts exhibited antimicrobial activities against the test organisms. Aqueous extract of Aloe vera juice had the highest antibacterial activity against K. pneumoniae at all the concentrations (50gm/ml, 25mg/ml and 12.5mg/ml) with the following mean zone diameters of 15.0 ± 0.02mm, 11.0 ± 01mm and 8.0 ± 0.04mm respectively. The ethanolic extract of the juice presented a zone diameter of 16.5 ± 0.01mm, 11.5 ± 0.02mm and 9.0 ± 0.01mmm at 50mg/Ml, 25mg/mL and 12.5mg/mL concentrations respectively. The least activity was recorded in P. aeruginosa with no zone of inhibitions at 25mg/ml and 12.5mg/ml concentrations in both juice extracts. The antifungal activity was not significant at P<0.05 in A. niger which was resistant in all the concentration except at 50mg/ml. The percentage weight yield of extracts was highest in the aqueous (70% and 60%) than in the ethanolic (30% and 40%) respectively. MIC was significantly different at P<0.05 for all the organisms except P. aeruginosa at 50mg/ml, for aqueous extracts of both juice and gel. At 25mg/ml and 12.5mg/ml concentration, there was no significant difference at P<0.05. The protective wall of gram-negative bacteria are known to hinder bioavailability of drug ingredients to organisms. The extracts of this plant possess compounds with antimicrobial properties, which will add credence to the ethano-medicinal use of this plant and since the plant is a reservoir for new bioactive compounds, it will contribute to the health care needs of developing and underdeveloped countries. Index Terms : Aloe vera, juice, gel, antimicrobial activity.