Commonly used in household products, the antimicrobial agents known as quaternary ammonium compounds, or “quats,” were found to inhibit mitochondria function and to impair estrogen signaling.
The findings raise serious questions regarding the safety of these products, which include toothpastes, shampoos, and lotions, among many others, as exposure to other mitochondrial-inhibiting drugs is known to increase the risk for Parkinson’s development.
The study, “In Vitro Evaluation of Mitochondrial Function and Estrogen Signaling in Cell Lines Exposed to the Antiseptic Cetylpyridinium Chloride,” was published in the journal Environmental Health Perspectives, a publication of the National Institute of Environmental Health Sciences.
“Disinfectants that we are putting on and in our bodies, and using in our environment, have been shown to inhibit mitochondrial energy production and the cellular estrogen response,” biochemist Gino Cortopassi of the UC Davis School of Veterinary Medicine and the study’s lead author, said in a press release.
“This raises concern because exposure to other mitochondrial-inhibiting drugs, such as rotenone and MPTP, is associated with increased risk for Parkinson’s disease,” he said.
Quats are currently being used in hand lotions, toothpastes, mouthwashes, nasal sprays, lozenges, deodorants, intravaginal sponges, and in multidose pharmaceutical formulations, such as eye drops, the team noted.
Researchers tested household products and pharmaceutical drugs in a total of 1,600 FDA-approved and clinically evaluated antiseptics, additives, and drugs, and assessed their impact in mitochondria and endocrine functions in lab-grown cells.
The result showed that quats impaired mitochondria function and inhibited estrogen signaling, one of the most important sex hormones in women.
“We performed a high-throughput screen of 1,600 antiseptics, additives, and drugs, and found that, of the numerous structural classes of compounds included in the screen, the QUATS were the most mitochondrially toxic class, both in terms of inhibition of ATP synthesis and mitochondrial O2 consumption,” researchers wrote.
Moreover, “because exposure to quats is also interrupting the sex hormone estrogen response in cells, it could also potentially cause reproductive harm in animals or humans, and others have shown that quats cause reproductive toxicity in animals,” Cortopassi explained.
A team at Virginia Tech had shown that exposure to quats caused reproductive toxicity and reduced fertility in mice, and led to neural tube birth defects in both mice and rats. The new findings might explain how this happens.
“Our study in cells provides a mechanism for their observations in laboratory animals,” said the study’s first author, Sandipan Datta, a postdoc researcher in Cortopassi’s laboratory. “They demonstrated that quat exposure caused reproductive toxicity in both females and males. The anti-estrogenic effects we see in cells could explain the female reproductive toxicity they observed, such as less estrus cycles and lower breeding rates.”
Widely used since the 1940s, quats were suggested to be a safe alternative to other antiseptics, such as triclosan, which was removed from the market after studies showed its use was detrimental to muscle function. This new research suggests that quats might not be safer, and carry noxious effects to cells and animals.
“This paper adds to the growing number of studies which find that quats may not be as safe as previously believed,” said Terry Hrubec, associate professor at Edward Via College of Osteopathic Medicine-Virginia, who was not involved in the research. “The fact that six out of the 10 most potent mitochondrial inhibitors were quats shows that this class of chemicals likely affects living systems. The results from this study are concerning because almost everyone is exposed to quats on a regular basis.”
In the future, the research team at UC Davis School of Veterinary Medicine is planning to further assess the long-term effects of quats in animals.