Rinse-off cosmetic products, primarily shampoos, are frequently implicated in the onset of allergic contact dermatitis (ACD) caused by alkyl glucosides (AGs). AGs are increasingly popular surfactants and known contact allergens. Glucoside-induced ACD was most frequently observed with shampoos and skin-cleansing products in both consumer and occupational settings. Thereby, studies have shown that atopic individuals are the most susceptible to ACD. Also, several investigations have indicated that individuals with sensitive skin might be more prone to skin allergies. This is why the presence of AGs was investigated in shampoos and body cleansers marketed as hypoallergenic or for sensitive skin. For this purpose, the website of Amazon.com was surveyed. Four groups of cosmetics were obtained by using the following keywords: \"hypoallergenic shampoo for adults,\" \"sensitive skin shampoo for adults,\" \"hypoallergenic body cleanser for adults,\" and \"sensitive skin body cleanser for adults.\" The first 30 best-selling cosmetics in each group were investigated for the presence of AGs, by analyzing the product information pages. The results showed that as much as 56.7% of hypoallergenic shampoos contained AGs, as ingredients, whereas the percentage was somewhat lower for other product categories. Even though decyl and lauryl glucoside were nearly ubiquitously used AGs in cosmetics over the past decade, the most commonly present AG in our analysis was coco-glucoside. The results of this study indicated a necessity to include coco-glucoside in the baseline series of patch testing allergens. Industry, regulators, and healthcare providers should be made aware of the frequent presence of AGs in rinse-off cosmetic products marketed as hypoallergenic or for sensitive skin to ensure the safety and well-being of consumers and patients.

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OBJECTIVE: To synthesize octyl β-D-glucopyranoside (OG) and decyl β-D-glucopyranoside (DG) in three non-aqueous reaction systems, namely organic solvents, ionic liquids and co-solvent mixtures, via reverse hydrolysis reactions catalyzed by the N189F dalcochinase mutant.
RESULTS: The highest yield of OG (67 mol%) was obtained in the reaction containing 0.5 M glucose, 3 unit ml-1 enzyme in 20% (v/v) octanol and 70% (v/v) [BMIm][PF6] at 30 °C. On the other hand, the highest yield of DG (64 mol%) was obtained in the reaction containing 0.5 M glucose, 3 unit ml-1 enzyme in 20% (v/v) decanol, 20% (v/v) acetone and 50% (v/v) [BMIm][PF6] at 30 °C. The identities of OG and DG products were confirmed by HRMS and NMR.
CONCLUSIONS: This is the first report of enzymatic synthesis of OG and DG via reverse hydrolysis reactions in ionic liquids and co-solvent mixtures. The N189F dalcochinase mutant and the non-aqueous reaction systems described here show great potential for future commercial production of long-chain alkyl glucosides.

Carbohydrates are appealing non-ionic surfactant head-groups as they are naturally abundant, generally biocompatible and biodegradable, and readily functionalized. Herein, we explore the phase behavior of seven novel carbohydrate-based surfactants (CBS) containing a tri-ethylene glycol (TEG) linker between a glucose head-group and alkyl tail-group, with linear saturated (C8-18) and cis-unsaturated (C18:1) alkyl chains. At high aqueous concentrations, these glycolipid-like surfactants transition into a variety of lyotropic liquid crystalline phases following an expected concentration phase sequence: hexagonal (H1) → bicontinuous cubic (V1) → lamellar (Lα). Using polarizing light microscopy (PLM), a binary (surfactant-water) phase diagram for each surfactant was constructed across a temperature range (25-80 °C) revealing thermotropic behavior and a broadening of liquid crystal phase regions with increasing alkyl chain length. There was also a significant difference between saturated and unsaturated alkyl chains, due to the cis-unsaturated \'statistical bend\' lowering the melting point. Small-angle X-ray scattering (SAXS) measurements were performed to characterize the liquid crystal phases, identifying highly-ordered p6m,Ia3d, and Lα crystallographic space-groups with up to 7 resolved Bragg peaks, likely due to the highly anisometric nature of the TEG-linked surfactants. The phases were shown to be more numerous and exhibited greater thermal-stability compared to well-characterized alkyl glucoside surfactants lacking an oligoethylene spacer in the literature. Finally, the characteristic dimensions of each phase were determined to enable visualization of the internal microstructures, providing insight into the impact of molecular shape and the distribution of hydro-philicity/phobicity on the formation and stability of liquid crystalline mesophases.

Development of many branches of industry has stimulated the search for new, effective surfactants with interesting properties. Potential use of alkyl glucose derivatives on a large scale, raises questions about the possible risks associated with their entry into the natural environment. To be able to evaluate this risk, the aim of the study was to determine the physicochemical properties of octyl d-glucopyranoside and its three derivatives: N-(octyl d-glucopyranosiduronyl)aspartic acid, N-(octyl d-glucopyranosiduronyl)glicyne and octyl d-glucopyranosiduronic acid. Moreover, their biodegradability by pure bacterial strains and biocenosis present in river water was examined. While descriptions of sugar-based surfactants on microbial cells are limited, the essential element of the study was to determine the effect of surfactants on cell surface properties of microorganisms isolated from activated sludge and compare it to the effects of the petroleum based surfactants and the surfactants produced from renewable materials. The results obtained indicate that physicochemical properties of surface active agents differ depending on the presence of functional groups in the surfactants molecules. What is more, the presence of amino acid substituent in the derivatives of octyl d-glucopyranoside resulted in a slight decrease in the surfactants biodegradation efficiency, in comparison to the compounds that did not contain such a substituent, prolonging this process from 5 to 10 days. Interestingly, even relatively slightly different derivatives modified the cell surface properties in a different way. Importantly, the surfactants based on octyl d-glucopyranoside have less negative impact on environmental microorganism and better biodegradability than the surfactant synthesized from petroleum products.

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Carbohydrates are appealing non-ionic surfactant head-groups as they are naturally abundant, generally biocompatible and biodegradable, and readily functionalized. Here, seven novel carbohydrate based surfactants (CBS) have been synthesized that contain a tri-ethylene glycol (TEG) linker between a glucose head-group and alkyl tail-group, with linear saturated (C8-18) and unsaturated (C18:1) alkyl chains. The aqueous adsorption and self-assembly of these surfactants was explored using tensiometry and small- and ultra-small-angle neutron scattering (SANS and USANS). With SANS we observed elongation from spherical to cylindrical micelles with increasing alkyl chain length. C16 and C18 chains exhibited pronounced Krafft points, yet formed worm-like micelles as single components upon heating to 43 and 48 °C respectively. The introduction of mono-unsaturation in the form of a C18:1 chain reduced the Krafft point and gave a surfactant that produced worm-like micelles in water without additives at room temperature. We also observed micellar elongation for C12 and C14 chains at 50 °C due to dehydration of the TEG linker. The room temperature worm-like micelles were further characterized using rheo-SANS and rheology, revealing the C18:1 surfactant to exhibit near ideal Maxwell behavior at low concentrations (2.9 wt.%). These results provide insight into structure-function relationships for CBS, and demonstrate a promising molecular candidate for the formation of viscoelastic worm-like micellar solutions.

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BACKGROUND: Alkyl glucosides were not expected to have a sensitizing potential at the concentrations to be used in finished consumer products; however, several contact allergy cases have been published.
OBJECTIVE: To report on the patients suffering from allergic contact dermatitis caused by alkyl glucosides observed in our department.
METHODS: During a 19-year period (1993-2012), 11 842 patients with suspected contact dermatitis were patch tested with the European baseline series and, if relevant, also with other series and individual allergens. For this study, the clinical data and the sensitization sources in the alkyl glucoside-positive patients were analysed.
RESULTS: In total, 30 patients (24 women and 6 men) presented with a positive reaction to one or more alkyl glucosides. The causal products were shampoos (in 12), skin-cleansing products (in 12, among which were wipes for intimate hygiene), sunscreen products (in 5), skin-care products (in 4), and a deodorant (in 1). Sixteen patients showed multiple sensitivities (defined as three or more contact allergies), not only to other glucosides, but also to non-related chemicals.
CONCLUSIONS: Allergic contact dermatitis caused by alkyl glucosides in cosmetics does occur, and might be more frequent than suspected. In view of their common use, their identification as allergenic culprits is important.