Sunscreens containing salicylate UV-filters may be breeding ground for pathogenic bacteria: Study

By Guan Yu Lim contact

- Last updated on GMT

Researchers from Israel think the SA produced is further incorporated into the metabolic cycle of P. aeruginosa and B. cepacian, hence promoting their growth despite the use of preservatives ©Getty Images
Researchers from Israel think the SA produced is further incorporated into the metabolic cycle of P. aeruginosa and B. cepacian, hence promoting their growth despite the use of preservatives ©Getty Images

Related tags: Sunscreen, Salicylic acid, Uv filters, Bacteria

Sunscreen formulations containing UV-filters such as octyl salicylate (OS) and homosalate (HS) may be breeding grounds for two pathogenic bacteria, Pseudomonas aeruginosa and Burkholderia cepacian, despite the presence of preservatives.

This was revealed in a new study which investigated the components in sunscreen and the interaction with the preservation system in promoting the growth of certain bacteria.

Sunscreen formulations are known to be difficult to preserve, due to their high ratio of organic phase containing the UV-filters.

OS and HS are one of the more common UV-filters used in the market, and undergo hydrolysis to produce salicylic acid (SA) which absorbs UV radiation, and is anti-inflammatory.

In this study, researchers think the SA produced is further incorporated into the metabolic cycle of P. aeruginosa​ and B. cepacian​, hence promoting their growth despite the use of preservatives.

P. aeruginosa​ is a pathogenic bacteria responsible for causing infections affecting the eye, while B. cepacia​ is an opportunistic pathogen and potentially fatal in immuno-compromised individuals, possessing a mortality rate of 42%, according to Amy Irwin and Connie Price (2008).

The findings were published in the journal Cosmetics.

Study design

Researchers believe that salicylate UV-filters may assist P. aeruginosa​ and B. cepacia​ against the preservative effect.

They tested this on three basic cream formulation containing the same preservative system (80% Phenoxyethanol, 5% Didecyldimethylammonium chloride, 10% Chlorophenesin, 5% Caprylyl glycol).

The first formulation did not contain any salicylate UV-filter, the second formulation was supplemented with 5% OS and the third with 5% HS.

In the first formulation, both P. aeruginosa​ and B. cepacia​ were unable to survive.

But in the second and third formulations, the preservative failed to inhibit P. aeruginosa​ and B. cepacia​ growth.

In fact, viability of P. aeruginosa​ increased in correlation to the increasing concentrations of OS, pointing out its positive effect on growth.

The researchers concluded that the UV-filters commonly used in sunscreen formulations may induce a signalling response which could result in a resistance against the common preservative used in the cosmetic industry.

SA may trigger a signaling cascade similar to a stress response in bacterial species, that eventually enhances their resistance against preservatives.

“Our results, supported by previous data, suggest that some bacterial species containing the chorismate pathway may confer a unique resistance mechanism which is triggered by the presence of certain UV-filters in common sunscreen formulations​,” they wrote.

 

Source: Cosmetics

https://doi.org/10.3390/cosmetics7030063

“Salicylate UV-Filters in Sunscreen Formulations Compromise the Preservative System Efficacy against Pseudomonas aeruginosa and Burkholderia cepacia”

Authors: Noa Ziklo, et al​.

Related news

Show more

Related products

show more

Tagra: Stabilizing Retinol to Rejuvenate Skin

Tagra: Stabilizing Retinol to Rejuvenate Skin

Tagra Biotechnologies | 03-Oct-2022 | Product Presentation

Retinol is widely regarded in the cosmetics industry as a golden ingredient for ageless skin. Yet, it tends to lose its efficacy quickly due to a variety...

Sensiva™ go natural,a protector without compromise

Sensiva™ go natural,a protector without compromise

Ashland Global Holdings Inc | 24-Jun-2022 | Technical / White Paper

Consumers are increasingly buying natural, organic beauty and wellbeing products as noted from the increasing number of product launches with natural claim...

Formulating for Clean Beauty

Formulating for Clean Beauty

Elementis | 26-May-2022 | Product Brochure

Water scarcity and water pollution continues to be a concern for the environment. Every year, about 130 tons of microplastic particles from personal care...

Follow us

Products

View more

Webinars

Indie Pioneers Podcast

Indie Pioneers Podcast