Benzophenones (inci)

Benzophenones (also known as diphenylmethanones) and its derivatives comprise numerous organic compounds, which belong to the ketones and aromatic hydrocarbons. Benzophenones are mainly produced synthetically. However, they also occur as natural products (in higher plants and fungi). Natural benzophenones are characterized by large structural and biological (antifungal, antiviral, antimicrobial, antioxidant) differences.

Benzophenones in technical areas: Benzophenones are used in technical areas as photoinitiators in UV curing applications (e.g. in inks - where contact allergic reactions can occur - Infante Hernando L et al 2013) and coatings in the printing industry). Benzophenones are also used in plastic packaging to protect it from destruction by UV radiation.

Benzophenones in cosmetic products: Benzophenones and various derivatives are used in cosmetics (Benzophenone-1 - Benzophenone-12) as UV absorbers for ingredients of creams, perfumes, soaps, hair shampoos.

Systemic absorption: When sun protection creams containing benzophenone-3 are applied locally over a large area, it is systemically absorbed and excreted in relevant quantities through the urine. The amount of excreted BP-3 correlated with the (assumed) application amount of Benzophenone-3 (Zamoiski RD et al.2015)

Benzophenones and allergological (+photoallergic) relevance: Cases of contact allergic and photoallergic reactions have been described mainly with benzophenone-3 (Haylett AK et al 2014). Otherwise, they are rarely observed despite the wide distribution in cosmetic products (e.g. sun creams) (Belezany K et al 2014). Rarely benzophenones (Benzophenone-4/ -5) occur as occupational contact allergens (hairdressing products). Eyelid eczema has been described after application of benzophenone-containing nail products.

Toxicological evaluation of benzophenone derivatives: The "International Agency for Cancer Research - IARC- currently classifies benzophenones as non-carcinogenic. https://monographs.iarc.fr/ENG/Monographs/vol101/mono101-007.pdf . The effects of benzophenone on human health and the environment are still under review.

Investigations of urban waste water have revealed relevant amounts of BP-4, and the resulting environmental impact is highly probable but still completely unresolved. (Molins-Delgado D et al. 2016). In BP-exposed zebrafish, benzphenone-4 interferes with the expression of genes involved in hormone pathways (Zucchi S et al. 2011). Further environmentally harmful effects are expected in the future.

Benzophenone derivatives are included in the standardized light protection substances (see photo patch test below).

1. Belezany K et al (2014): Analysis of the prevalence of allergic contact dermatitis to sunscreen: a cohort study. J Cutan Med Surg 18: 15-19
2. European Multicentre Photopatch Test Study (2012) Br J Dermatol 166:1002-1009.
3. Haylett AK et al (2014) Sunscreen photopatch testing: a series of 157 children. Br J Dermatol 11: 370-375
4. Infante Hernando L et al (2013): Photoallergic contact dermatitis caused by benzophenones in magazine inks. Contact Dermatitis 69: 124-126
5. Molins-Delgado D et al (2016) Ecological risk assessment associated to the removal of endocrine-disrupting parabens and benzophenone-4 in wastewater treatment.1 J Hazard Mater 310:143-151.
6. Wu SB et al. (2014) Structural diversity and bioactivities of natural benzophenones. Nat Prod Rep 31:1158-1174.
7. Zamoiski RD et al (2015) Self-reported sunscreen use and urinary benzophenone-3 concentrations in the United States: NHANES 2003-2006 and 2009-2012. Environ Res 142:563-567 .
8. Zucchi S et al (2011) The UV-absorber benzophenone-4 alters transcripts of genes involved in hormonal pathways in zebrafish (Danio rerio) eleuthero-embryos and adult males. Toxicol Appl Pharmacol 250:137-146.
9. Zug KA et al (2014) Patch testing in children from 2005 to 2012: results from the North American contact dermatitis group. Dermatitis 25:345-55.