In Vitro Susceptibilities of Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa and Escherichia coli to the inner Gel of Aloe nuttii Baker and Aloe chabaudii Schonland found in Zambia

Abstract

The genus Aloe has a long history of medicinal usage in the world and is believed to treat various ailments. It contains bioactive compounds that work synergistically against various microbes. A comparative study of the two Zambian Aloe species Aloe nuttii Baker and Aloe chabauddii was done with the objectives to determine the antimicrobial activity, the minimum inhibition concentration and the susceptibility of microbes namely Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa and Escherichia coli. The study was a quantitative, comparative laboratory study. A Liquid-Liquid extraction method modified from Marjory Cowan, 1999, was used. The extracts were tested on microbes using the Agar Disk Diffusion Method modified from Kirby Bauer, 1966, and assessed by the growth inhibition zones. The two-fold dilution method modified from Doughari, 2007, was used to find the Minimum Inhibitory Concentration. Only the water extracts of Aloe nuttii Baker inhibited the growth of all the five microbes tested as indicated by the growth inhibition zones as follows: S. aureus 12±2mm, S.spp.10.3±0.7mm, P. aeruginosa 9.3±1.7mm, E. coli 10.7±1.3mm and Candida albicans 14±0.6mm. In contrast, Aloe chabaudii extracts displayed no antimicrobial activity. The MIC of Aloe nuttii Baker was found to be 1500mg/ml for Candida albican, P. aeruginosa and E. coli and 3000mg/ml for S. aureus. In contrast, Aloe chabauddi did not inhibit any microbial growth. In vitro, Staphylococcus aureus, Candida albicans, Pseudomonas aeriginosa, and Escherichia coli were susceptible to the inner gel of aloe nutty baker but showed no susceptibility to the inner gel of aloe chabaudii schonaland, which is found in Zambia.