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Chiral Skin Care

By: Shyam Gupta, PhD, and Linda Walker
Posted: November 5, 2010, from the November 2010 issue of GCI Magazine.
Chiral Skin Care

The left-handed and right-handed molecules usually have different physical, chemical and biological properties.

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Chirality in alpha-tocopherol (vitamin E): There are eight isomers of alpha-tocopherol that differ in the arrangement of groups around those chiran centers. Natural alpha-tocopherol is the D-alpha form, and the synthetic form (DL-alpha) is not as active as the natural tocopherol form. Therefore, the synthetic DL-alpha-tocopherol probably has only about half the vitamin activity of natural D-tocopherol in humans.

Chirality in lipoic acid: There is a carbon atom in lipoic acid that is chiral and the molecule exists as two enantiomers (a left-hand and a right-hand)—R and S—that are pharmacologically distinct. Only the R occurs naturally. Lipoic acid has been found to increase the production of glutathione, responsible for glucose uptake in cells, and R has been shown to do be more effective than S or a mixture of the two.

Chirality in amino acids: Of the 23 alpha-amino acids important in human biology, all but one (glycine) are chiral. These amino acids play a vital role in natural skin care, the production of skin and hair protective colorant (melanin), urocanic acid (sunscreen), cellular turnover and protein synthesis are among those roles. L-tyrosine and L-dopa amino acids are used in hair-darkening formulations, and the inhibition of L-tyrosine and L-dopa synthesis (tyrosinase inhibitors) is used for skin-whitening applications.

As brand owners and their partners push the technology envelope for beauty, recognizing the biological importance of chiral ingredients and their applications is a good foundation for uncovering opportunities, efficiency to market and making an impact with consumers.

Shyam Gupta is a consultant in skin and hair care ingredients and topical delivery systems. He specializes in nature-and science based formulations with enhanced efficacy and consumer desirable performance attributes. 1-602-996-9700; shyam@biodermresearch.com; www.biodermresearch.com