Phenol peels classification

For phenolics in fruit by-products such as apple seed, peel, cortex, and pomace, an HPLC method was also utilized. Apple waste is considered a potential source of specialty chemicals (58,62), and its quantitative polyphenol profile may be useful in apple cultivars for classification and identification. Chlorogenic acid and coumaroylquinic acids and phloridzin are known to be major phenolics in apple juice (53). However, in contrast to apple polyphenolics, HPLC with a 70% aqueous acetone extract of apple seeds showed that phloridzin alone accounts for ca. 75% of the total apple seed polyphenolics (62). Besides phloridzin, 13 other phenolics were identified by gradient HPLC/PDA on LiChrospher 100 RP-18 from apple seed (62). The HPLC technique was also able to provide polyphenol profiles in the peel and cortex of the apple to be used to characterize apple cultivars by multivariate statistical techniques (63). Phenolic compounds in the epidermis zone, parenchyma zone, core zone, and seeds of French cider apple varieties are also determined by HPLC (56). Three successive solvent extractions (hexane, methanol, aqueous acetone), binary HPLC gradient using (a) aqueous acetic acid, 2.5%, v/v, and (b) acetonitrile fol-... 

According to the classification of A. Tenenbaum, which is described later in this chapter, peelers should be careful with the dangerous distinction between so called cosmetic , peelings for acids with pK, > 3 and medical , peelings for acids with pK, < 3, because some adds like salicylic acid with a pK, near 3, as the phenol, toxic substance with a pKa > 3 need to be exclusively used by trained physicians. 

The usual classification of chemical peels comprises superficial, medium and deep peels. For superficial peels, AHA, Jessner s solution, tretinoin, TCA in concentrations of 10-30% and most recently hpo-hydroxy add are used to induce an exfoliation of the epidermis. Medium-depth agents such as TCA (30-50%) cause an epidermal to papillary dermal peel with subsequent regeneration. Deep peels using TCA (>50%) or phenol-based formulations penetrate the reticular dermis to induce dermal regeneration. The success of peeling in darker skin is crudally dependent on the physician s understanding of the chemical and biological processes, as well as of indications, clinical effectiveness and side effects of the procedure (see Box 9.1). 

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See also in sourсe #XX -- [ ]

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