Alpha hydroxy acids chemical structure

It is a lipophilic compound which removes intercellular lipids that are covalently linked to the cornified envelope surrounding epithelial cells [3]. It also enhances penetration of other agents. Resorcinol (m-dihydroxy benzene) is structurally and chemically similar to phenol. It disrupts the weak hydrogen bonds of keratin [4]. Lactic acid is an alpha hydroxy acid which causes corneocyte detachment and subsequent desquamation of the stratum corneum [5]. 

The structure of ascorbic acid resembles an alpha-hydroxy acid, which is generally not appreciated. Ascorbic acid is present in most fruits, and may underlie some of the effects attributed to fruit extracts. Vitamin C has pronounced HA-stimulating effects in the fibroblast assay. But its antioxidant activity confounds the effects it may induce. The deposition of HA is stimulated when Vitamin C is added to cultured fibroblasts. The most profound changes occur in the compartmentalization of HA. The preponderance of the enhanced HA becomes cell-layer instead of being secreted into the medium.240,261 The chemical reactions catalyzed by ascorbic acid that bind HA to cell or matrix components are not known. 

General chemical structure of an alpha-hydroxy acid, a indicates the alpha carbon atom R represents a general organic group. 

Figure 13.11. structure of cyclosporine A, an 11 amino-acid cyclic peptide. Cyclosporine is chemically designated as [R-[R, R -( fj]]-cyclic(L-alanyl-D-alanyl-A/-methyl-L-leucyl-A/-methyl-L-leucyl-A/-methyl-L-valyl-3-hydroxy-A/,4-dimethyl-L-2-amino-6-octenoyl-L-(alpha)-amino-butyryl-A/-methylglycyl-A/-methyl-L-leucyl-L-valyl-A/-methyl-L-leucyl). 

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