Comparison of Color Development Kinetics of Tanning Reactions of Dihydroxyacetone with Free and Protected Basic Amino Acids

Abstract

Sunless tanning has become incredibly prevalent due to the increasing fashionable demand and the awareness of photodamage risks. The brown pigments are induced by dihydroxyacetone (DHA) and amino groups in the stratum corneum (SC) of skin via the Maillard reaction. While most studies concerning sunless tanning reactions have focused on free amino acids (AAs), little information is available on the impact of the side chain of AAs or proteins on this important reaction in cosmetic chemistry. To explore the reactivity and color development kinetics of different types of amino groups, three basic free AAs (Arg, His, and Lys) and three Nαprotected AAs (Boc-Arg-OH, Boc-His-OH, and Boc-Lys-OH) were used to react with DHA using a simplified model system at different reaction times, pH, and temperatures. Full factorial experiments were employed to design and analyze the effects of these three factors. The browning intensity and color characteristics were quantitatively evaluated. The factorial experiments showed that temperature had the most significant influence on the browning intensity and played a dominant role in the interactions with the reaction time and pH. It was found, for the first time, that Arg and His reacted with DHA more rapidly than Boc-Arg-OH and Boc-His-OH, while Boc-Lys-OH developed a stronger color than Lys under the same conditions, suggesting that ε-NH 2 of a lysine residue in peptides or proteins of SC may play a crucial role in the color development of DHA tanning. This study not only clearly illustrates the capability of the side chain of AAs to produce colored compounds but also provides a deeper understanding of DHA tanning.

The Biosynthesis of Liquid Fuels and Other Value-Added Products Based on Waste Glycerol—A Comprehensive Review and Bibliometric Analysis

“…It may be produced by immobilised strains of Acetobacter xylinum upon glycerol oxidation [130] and synthesised by Gluconobacter oxydans, which uses glycerol as a carbon source [131]. Dihydroxyacetone is mainly used for the production of self-tanning lotions, and the skin colour achieved after using such cosmetics is the result of a chemical reaction with the amino acids contained in the stratum corneum of the epidermis [132]. Fermentation carried out by Actinobacillus succinogenes with glycerol as a carbon source produces succinic acid [133].…”

Properties and safety of topical dihydroxyacetone in sunless tanning products: A review

“…Currently, the Food and Drug Administration (FDA) authorizes its use for this purpose in externally applied cosmetics intended for skin tanning 5 . Sunless tanning products containing DHA in concentrations ranging from 1% to 15% have exponentially increased in popularity in recent times due to the growing spotlight on the deleterious effects of ultraviolet (UV) radiation exposure from the sun 4 . Despite the increased use of sunless tanning practices, reviews on the safety and toxicity of these products remain limited.…”

“…At times, when the solution was regurgitated, it was found to induce a darkening of the exposed skin 2,3 . Upon application to the skin, DHA reacts with amino acids such as arginine, histidine, and lysine in the stratum corneum to produce brown‐black chromophores known as melanoidins, a reaction known as the Maillard reaction 4 . This unexpected discovery subsequently led to worldwide utilization of DHA as the active ingredient in sunless tanning solutions 2 .…”

“…2,3 Upon application to the skin, DHA reacts with amino acids such as arginine, histidine, and lysine in the stratum corneum to produce brown-black chromophores known as melanoidins, a reaction known as the Maillard reaction. 4 This unexpected discovery subsequently led to worldwide utilization of DHA as the active ingredient in sunless tanning solutions. 2 Currently, the Food and Drug Administration (FDA) authorizes its use for this purpose in externally applied cosmetics intended for skin tanning.…”