Promoting Collagen with Glycerophospholipids and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: September 29, 2009, from the October 2009 issue of Cosmetics & Toiletries.

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Promoting collagen with glycerophospholipids: Unitika Ltd. has published on collagen production promoters containing glycerophos pholipids.⁵ The company aimed to develop inexpensive, safe and effective collagen promoters for the food, drug and cosmetics industries to improve skin aging and roughness. The collagen production promoter disclosed contains the active ingredient glycerophospholipid—specifically a glycerophospholipid such as phosphatidylcholine, lysophosphatidylcholine, phosphatidylserine, lysophosphatidylserine, phosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylinositol, lysophosphatidylinositol, phosphatidic acid, lysophosphatidic acid, phosphatidylglycerol or lysophosphatidylglycerol. In addition, the active has an unsaturated fatty acid as part of its structure. The effect of 1,2-dioleoyl-sn-glycero-3-phosphate sodium salt (DOPA Na) on collagen production in cultured human fibroblast NHDF cells was thus examined.

Particle coating to decrease TiO₂ damage to cells: Pan et al. have published on the adverse effects of rutile and anatase titanium dioxide nanoparticles on human dermal fibroblasts as well as an approach to protect cells from this damage via a particle coating.⁶ Both types of particles can impair cells—decreasing cell size, proliferation, mobility and their ability to contract collagen; however, anatase particles are the most damaging. Individual particles were shown to penetrate easily through the cell membrane in the absence of endocytosis while some endocytosis was observed for larger particle clusters. Once inside, the particles are sequestered in vesicles, which continue to fill up with increasing incubation time until they rupture.

These particles were therefore coated with a dense grafted polymer brush and tested. Using flow cytometry, the coated particles were shown to prevent adherence to the cell membrane and thus penetration into the cell, which effectively decreases the formation of reactive oxygen species (ROS) and protects the cells, even in the absence of light. Considering the broad applications of titanium dioxide nanoparticles in personal health care products, the functionalized polymer coating could play a potentially important role in protecting cells and tissue from damage.

Hair and Hair Care
Permanent hair straightening: Ogawa et al. have published on the chemical reactions the occur during permanent hair straightening using thioglycolic acid (TGA) and dithiodiglycolic acid (DTDGA).⁷ For decades, a curing method for hair straightening has been practically applied that consists of the reduction of the hair molecule followed by washing, heat treatment and oxidation. Two different reduction systems were examined by the authors: one containing TGA only and the other a bicomponent system containing TGA and DTDGA. The reaction mechanism was proposed on the basis of amino acid analysis of hair samples obtained at various treatment steps. New equilibrium reactions were assumed to be established in the reduced fiber after washing, which could successfully explain the experimental results.

When TGA is used for the reduction, hair is severly damaged due to the formation of mixed disulfide groups. Thus, when the TGA-only system was examined, mixed disulfide groups were formed in the hair fiber and the number of groups incorporated was dependent upon the concentration of TGA. In the heat-treatment step at 180°C for 3 sec, the mixed disulfide groups were wholly converted into the thiol groups of cysteine residues.