Abstract
Objective: To summarize evidence regarding the toxic potential of administering parabenscontaining cosmetics in humans. Methods: The systematic review followed the methodology proposed in Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA). Electronic searches of the PubMed, Virtual Health Library (BVS), and Science Direct databases were performed between October 1st and 31st, 2018. No language restriction was determined. Original articles reporting observational, in vitro and in silico studies of toxicity caused by parabens in human or human cells were considered for eligibility. Two independent reviewers performed data extraction and assessed the methodological quality and risk of bias of articles by using the Downs & Black Scale. Score levels greater than 70% were assumed to reflect good methodological quality. The Kappa coefficient was calculated. Results: A total of 254 studies were found. Following the eligibility evaluation, 22 studies were included for the qualitative synthesis. The concordance between the reviewers was substantial (Kappa coefficient = 0.650). The meaningful reported outcomes were: high concentrations of parabens in the body; apoptosis damage to sperm DNA; oxidative stress; DNA damage; irritative potential; interference in the control of adipogenesis; estrogenic activity; genotoxicity; necrosis; role in carcinogenesis of breast cancer; harmful effects on human skin when exposed to the sun; stimulation of oncogenes expression; and interference with DNA transcription. Despite most included articles presenting appreciable methodological quality, remarkable limitations were observed and the mechanisms by which parabens exert toxicity on humans remained unclear. Conclusions: The accumulation of parabens in the human organism following repeated cosmetics administration on the skin is noteworthy. However overall, the evidence so far does not make it possible to determine whether, and in what extent, the use of paraben-containing cosmetics can disturb human health. Further investigations are still required for clarifying these issues.
Highlights
Parabens are esters derived from parahydroxybenzoic acid used as preservatives in the manufacture of several cosmetic, pharmaceutical and food products[1]
The results indicated that exposure to parabens in early pregnancy was associated with purine metabolism, betaoxidation of fatty acids, metabolism of tryptophan and other pathways that were altered by parabens
Motivated by the large cosmetics consumption in Brazil and abroad, we report in this paper a systematic literature review of the toxic potential of the use of parabens as preservatives in cosmetic products
Summary
Parabens are esters derived from parahydroxybenzoic acid used as preservatives in the manufacture of several cosmetic, pharmaceutical and food products[1]. The parabens class of preservatives was introduced in the 1920s due to their broad spectrum of action against fungi, yeasts, and bacteria; remarkable compatibility with several raw materials; a wide range of pH and temperature stability; affordability; regulatory acceptance; and the need of low concentrations to exert antimicrobial effects, i.e., from 0.01 up to 0.3%2. Such class includes methyl, ethyl, propyl, butyl, pentyl, phenyl and benzylparabens. The preservative properties of parabens are driven by a structureactivity relationship, and vary according to the extent of the carbon chain i.e., the greater the number of carbons and the length of the chain, the greater the antimicrobial activity, the greater lipophilicity, and the lower solubility in water[3,4]
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