Phytosphingosine for Skin Differentiation and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: December 1, 2009, from the December 2009 issue of Cosmetics & Toiletries.

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Additional penetration studies of phytosphingosine formulated with cosmetic oils of different polarity were conducted using dermatomed pig skin in Franz cells. Penetration experiments clearly showed that the biological skin delivery of phytosphingosine depends on the polarity of the emollient, with polar oils providing the greatest penetration.

Further evaluation of the biological effects of phytosphingosine was accomplished in vitro by applying the test formulations to reconstructed human epidermis, followed by RT-qPCR analysis of selected genes relating to keratinocyte differentiation. Using this approach, the study further demonstrated that the biological effect of phytosphingosine on keratinocyte differentiation in reconstructed human epidermis is clearly dependent on its bioavailability, which is determined by the polarity of the cosmetic oil.

In conclusion, the researchers demonstrated that phytosphingosine promotes keratinocyte differentiation and is therefore a viable active ingredient for cosmetic applications whose biological activity can be enhanced by the use of an appropriate formulation.

Artificial dermis wrinkle model: Shiseido Co. has patented an artificial dermis wrinkle model, its manufacture and an antiwrinkle ingredient evaluation method.² The artificial dermis wrinkle model is made with contraction collagen gel-containing fibroblasts and can be used for the validation of antiwrinkle ingredients.

Hair and Hair Care
Minimizing dye damage to hair with gallnut and Eclipta prostrata: Amorepacific Corp. disclosed a hair dye containing gallnut and/or Eclipta prostrata extract in the first agent, along with an oxidative dye precursor, a coupler and alkaline chemicals, while the second agent contained an oxidant.³Gallnut and Eclipta prostrata are natural antioxidants and were combined with water-soluble antioxidants and reducing agents in the first agent to prevent oxidation, thus maintaining the stability of the ingredients and dyes. This in turn improved the dyeability of hair and minimized damage.