ROKer question concerning Coumarin in cosmetics

ROKer- Roosa, asked:

“Are you worried about products containing coumarin? I know there’s been quite a bit of back and forth on its toxicity, but it is widely used. What’s your take? Also, a post on your take on the teratogenic effects of parabens would be highly appreciated”

I’m very exited about this question! The dangers of PABA’s are in the wind these days, and coumarin is an ingredient I need to know more about, so this question is right up my ally!

Lets have a look at Coumarin first, as I think a post on both would be a little science heavy for one day.

Coumarin (anhydride of o-coumaric acid) is a white, crystalline lactone, obtainable naturally from several plants, such as tonka bean, lavender, sweet clover grass, strawberries, and cinnamon, or produced synthetically from an amino acid, phenylalanine. Coumarin has a characteristic odour like that of vanilla beans. It is used for the preparation of flavours and fragrances.

Coumarin is a widely used fragrance ingredient. It was found in 57% of 73 deodorants on the European market in a 1998 published study (Rastogi et al 1998). It is also used in medicine as an anticoagulant (inhibitor of blood-clot formation).

There are a number of articles on the effects of coumarin, ranging from hepatotoxic effects (liver toxic), when ingested in foods in higher quantities, to being used as a treatment modality in cancer! Coumarin has been established to be moderately toxic to the liver and kidneys, with a "Median Lethal Dose" of 275 mg/kg, which is low compared to related compounds.

Regarding skin, it is only somewhat associated to hypersensitivity, or allergies, as found by the European Commission - Health & Consumer protection Directorate:  “Coumarin has caused allergic reactions on 1.2 - 6.8% of patients suspected for fragrance contact allergy, (ref.: SCCNFP/0017/98 and 11). “

Coumarin is prohibited as an additive to food, and is restricted in cosmetics, due to its activity as a skin- allergen (substance causing allergy).

Since it is only moderately associated to skin allergies, I’m not very concerned with the appearance of coumarin in cosmetics, as most individuals will not be affected by it, and because there are no substantial evidence of coumarin as a carcinogen (agent causing cancer). Coumarin is also not bioaccumulative, so it will not build up in our body past exit from it. Rather than being harmful it has been associated to restored function in macrophages (scavenger cells of the immune system), skin-tumor suppression in both mouse skin pappilomas as well as in human melanoma cells, antibacterial activity, in addition to having broad anticancer effects in a number of non-skin cancers, such as breast and stomach.

Sources:

Chemical composition and antibacterial activity of the essential oils from Launaea resedifolia L

Amar Zellagui,1 Noureddine Gherraf,1 Segni Ladjel,2 and Samir Hameurlaine2

Org Med Chem Lett. 2012; 2: 2.

Published online 2012 January 20. doi:  10.1186/2191-2858-2-2

PMCID: PMC3395870

Anti-oncogenic potentials of a plant coumarin (7-hydroxy-6-methoxy coumarin) against 7,12-dimethylbenzaanthracene-induced skin papilloma in mice: the possible role of several key signal proteins

Journal of Chinese Integrative Medicine: 2010; 8(7): 645-654 DOI: 10.3736/jcim20100708

Polymeric nanoparticle encapsulation of a naturally occurring plant scopoletin and its effects on human melanoma cell A375

Journal of Chinese Integrative Medicine: 2010; 8(9): 853-862 DOI: 10.3736/jcim20100909

Studies on Cancer Chemoprevention by Traditional Folk Medicines XXIV.—Inhibitory Effect of a Coumarin Derivative, 7-Isopentenyloxycoumarin, against Tumor-Promotion

Masaki Baba1), Yongri Jin1), Atsuo Mizuno1), Hisaya Suzuki1), Yoshihito Okada1), Nobuo Takasuka2), Harukuni Tokuda3), Hoyoku Nishino3), Toru Okuyama1)

Biological and Pharmaceutical Bulletin Vol. 25 (2002) No. 2 P 244-246

EUROPEAN COMMISSION HEALTH & CONSUMER PROTECTION DIRECTORATE-GENERALSCCP /0935/05

Directorate C - Public Health and Risk Assessment

C7 - Risk assessment