Estrogenic activity of UV filter mixtures

Area of Science:

• Environmental Chemistry
• Endocrinology
• Toxicology

Background:

• UV filters are common in sunscreens and cosmetics for UV protection.
• Some UV filters exhibit estrogenic activity, but their combined effects in mixtures are poorly understood.

Purpose of the Study:

• To analyze the estrogenic activity of 8 common UV filters in equieffective mixtures.
• To evaluate interactions between UV filters and 17 beta estradiol (E2).

Main Methods:

• Utilized a recombinant yeast assay with human estrogen receptor alpha (hERalpha).
• Assessed mixtures of 2, 4, and 8 UV filters at various effect levels and no-observed-effect-concentrations (NOEC).
• Employed concentration addition (CA) and independent action (IA) models for effect prediction.

Main Results:

• Most binary mixtures of pure hERalpha agonists showed synergistic estrogenic activity.
• Synergistic activity was observed in mixtures of 4 or 8 UV filters, even at concentrations below individual NOECs.
• Antagonistic activity was noted only with benzophenone-1 in specific combinations.

Conclusions:

• Significant synergistic interactions occur in UV filter mixtures, impacting their overall estrogenic activity.
• These findings are critical for accurate hazard and risk assessments of personal care products containing UV filters.