SOROCABA, Brazil—According to a new Brazilian study, xylitol—natural sugar alcohol derived from plants, fruits and vegetables—has antimicrobial activity and could be considered as an alternative preservative for cosmetic formulations (Intl J Cosmet Sci. Feb. 21, 2011). Researchers aimed to evaluate the antimicrobial effectiveness of C-8 xylitol monoester, for its use as a preservative in cosmetic formulations. The minimum inhibitory concentration (MIC) was determined by the broth macrodilution method, and the antimicrobial effectiveness of C-8 xylitol monoester was determined by using challenge test method.
The results obtained in the determination of minimum inhibitory concentration were between 1 percent and 1.25 percent for Staphylococcus aureus, Escherichia coli and Candida albicans and between 1 percent and 1.5 percent for Pseudomonas aeruginosa and Aspergillus niger. The amount of 1 percent of C-8 xylitol monoester was added to the lotion used in the challenge test, observing a rapid decline in the number of CFU g−1 in stages of evaluation after contamination of the product by all bacteria. The same occurs in relation to C. albicans, which showed a 90-percent reduction in the number of CFU g−1. Regarding A. niger, a similar reduction was observed when pH value of the lotion was adjusted from 5.5 to 7.0.