Bacterial toxicity testing and antibacterial activity of parabens

ABSTRACT

Parabens are used because of their antimicrobial effects, yet they have multiple adverse effects. The aim of this work was to evaluate the bactericidal activity and bacterial toxicity of the most common parabens: methylparaben, ethylparaben, propylparaben, isopropylparaben, butylparaben, isobutylparaben and phenylparaben. The bactericidal action was evaluated by means of the dilution-neutralization method against Escherichia coli and Staphylococcus aureus, and the biotest of inhibition of growth of E. coli was applied for the bacterial toxicity assay. Bactericidal concentrations were reached only for propylparaben, butylparaben and isobutylparaben. The toxicity study showed methylparaben to be the least toxic, whereas the most toxic one was phenylparaben. It can be concluded that the disinfectant activity of the parabens studied is insignificant against S. aureus and E. coli. Acute toxicity is very low, and the inhibitory effect is weak. Our results provide information about the risk–benefit balance of parabens use.

KEYWORDS:

• Bactericidal effect
• dilution-neutralization
• disinfectant
• Escherichia coli
• parabens
• Staphylococcus aureus

Acknowledgments

We would like to acknowledge César Criado Sánchez, laboratory technician of the Department of Preventive Medicine and Public Health, Faculty of Pharmacy, University of Granada, Spain, for his invaluable help in making this study possible. We also thank Jean Louise Sanders for translating and editing the manuscript.

Disclosure statement

The authors declare that there are no conflicts of interest.