Alkyl Glucosides Research Articles

A furan-2-carbonyl C-glucoside and an alkyl glucoside from the parasitic plant, Dendrophthoe pentandra

A new furan-2-carbonyl C-(6′-O-galloyl)-β-glucopyranoside (scleropentaside F, 1) and a new alkyl glucoside [butane-2,3-diol 2-(6′-O-galloyl)-O-β-glucopyranoside, 2] were isolated from the entire hemi-parasitic plant, Dendrophthoe pentandra growing on Tectona grandis together with ten known compounds including, benzyl-O-β-d-glucopyranoside (3), benzyl-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (4), benzyl-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (5), methyl gallate 3-O-β-d-glucopyranoside (6), methyl gallate 3-O-(6′-O-galloyl)-β-d-glucopyranoside (7), (+)-catechin (8), procyanidin B-1 (9) and procyanidin B-3 (10), bridelionoside A (11), and kiwiionoside (12). In addition, compounds 1, 3–9 were isolated from this species growing on the different host, Mangifera indica. The structure elucidations were based on physical data and spectroscopic evidence including 1D and 2D experiments.

Micellar effect on the direct Fischer synthesis of alkyl glucosides

This manuscript presents results from the investigation on the synthesis of alkyl glucosides by the novel, very efficient and environmentally friendly protocol of the Fischer-type synthesis from unprotected glucose and aliphatic alcohols. The use of the dual functionality catalysts (surfactant+acid catalyst) and micellar reaction system are the main novelty of described method. It has been found, that in developed method of synthesis the reaction of unprotected glucose with aliphatic alcohols carried out with significantly different route, than the normal (classical) route and leads to alkyl glucopyranoside derivatives with high yields. In progress analyses by DLS, HPLC and GC/MS confirm the general postulated pathway of developed method.

β-Glucosidase from Streptomyces griseus: Nanoparticle immobilisation and application to alkyl glucoside synthesis

A novel β-glucosidase from Streptomyces griseus was cloned and overexpressed in E. coli. The purified β-glucosidase (44 kDa) had a Km of 8.6 ± 0.5 mM and a Vmax of 217 ± 5.0 μmoles−1min−1mg at 37 °C, pH 7.2 with p-nitrophenyl-β-D glucopyranoside as substrate. The enzyme was characterised in terms of pH optimum (pH 6.9), temperature optimum (69 °C) and the influence of solvents and effectors. Purified S. griseus β-glucosidase was successfully immobilised, by simple absorption, onto zinc oxide (ZnO) nanoparticles without covalent modification. It remained tightly bound even after extensive washing and could be reused up to ten times without significant loss of activity. The immobilised enzyme had a higher optimum temperature and greater thermostability than the free enzyme. In immobilised form the enzyme readily catalysed the synthesis of alkyl glucosides.

Ring opening of epoxidized methyl or ethyl oleate by alkyl glycosides

Epoxidized methyl or ethyl oleate were used as models of FAtty Methyl Esters to explore their functionalization via ring opening of the internal epoxide by alkyl glycosides. Overcoming solubility issues, medium to long‐chain alkyl glucosides gave better results than methyl glucoside. Er(OTf)3 turned out to catalyze at room temperature the selective formation of hydroxyalkylethers with good yields versus transesterification, despite the concomitant formation of fatty ketones. A brief scope of the reaction, using several available alkyl glycosides, suggests that the strategy can easily lead to new highly functionnalized amphiphilic compounds, potential precursors for biobased materials.Practical applications: Interested in the formation of original high‐value intermediates from renewable materials, we tackled the reaction of unprotected carbohydrates and unsaturated vegetal oils featuring an internal epoxide. After ring‐opening, the obtained highly functionalized polyols are potential precursors to produce new biobased polymers, lubricants or surface‐active compounds for high‐value cosmetic or biopharmaceutical formulations.The formation of hydroxyalkylethers from epoxidized fatty esters and alkyl glycosides are catalyzed by Er(OTf)3 at room temperature with good yields and high selectivity versus transesterification.

Alkyl Glucosides in Contact Dermatitis.

Ecologically sound because they are synthesized from natural and renewable sources, the mild surfactants alkyl glucosides are being rediscovered by the cosmetic industry. They are currently found in rinse-off products such as shampoos, liquid cleansers, and shower gels, but also in leave-on products that include moisturizers, deodorants, and sunscreens. During the past 15 years, numerous cases of allergic contact dermatitis have been published, mostly to lauryl and decyl glucosides, and these compounds are considered emergent allergens. Interestingly, the sunscreen Tinosorb M contains decyl glucoside as a hidden allergen, and most cases of allergic contact dermatitis reported to this sunscreen ingredient are probably due to sensitization to decyl glucoside. This article will review the chemistry of alkyl glucosides, their sources of exposure, as well as their cutaneous adverse effects reported in the literature and encountered in various patch testing centers.

Alkyl Glucosides.

Alkyl glucosides are surfactants synthesized through the condensation of long-chain fatty alcohols and glucose, extracted from vegetal, renewable sources. Although available for more than 4 decades, they have been rediscovered in recent years because of their eco-friendly character. They are used in various leave-on and rinse-off cosmetics and are considered of low irritancy and allergenicity. However, since the early 2000s, cases of allergic contact dermatitis to this family of molecules have been repeatedly reported. Decyl glucoside was found to be a "hidden" allergen in the sunscreen ingredient Tinosorb M and is likely responsible for most allergic contact dermatitis reported to this compound. Members of the North American Contact Dermatitis Group have seen a steady increase of the rate of sensitization to decyl glucoside. Cross-reactions with other glucosides are common but not automatic; thus, patch testing multiple compounds is recommended.

Conformations of n-alkyl-α/β-d-glucopyranoside surfactants: Impact on molecular properties

Sugar-based surfactants are amphiphilic compounds bearing a head group derived from sugar. Such surfactants represent a good alternative to petroleum-based surfactants, because they can be prepared from bioproducts and generally have a low toxicity. The conformational flexibility of sugars is well known and since they can form competitive intramolecular hydrogen bonding-like interactions, the most stable conformations are often non-trivial. Calculating molecular descriptors in the context of Quantitative Structure-Property Relationship (QSPR) studies require relevant conformations. To find such conformations and then develop QSPR models, in this study, we carried out a conformational analysis of two anomers, octyl α-d-glucopyranoside and octyl β-d-glucopyranoside, to exhibit the main conformational parameters of glucopyranosides and their influence on some quantum chemical molecular descriptors that could be used in QSPR models of surfactants. From a starting set of 26 conformations for each anomer, optimized at B3LYP/6-31+G(d, p) level of Density Functional Theory, three most significant conformations, common for both glucopyranosides, generated by changing a single dihedral angle, were highlighted as the most significant conformations. The influence of solvent modeled by an implicit solvation model on conformations was discussed. Moreover, the influence of conformations on calculated molecular properties (partial charges, polarisability, and dipole moment) was discussed, for n-alkyl α/β-d-glucopyranosides. It was shown that for the studied alkyl glucosides, the dipole moment is influenced by the choice of conformations, but that the polarisability and the partial charges are less so.

Transformation of Cellulose into Nonionic Surfactants Using a One-Pot Catalytic Process.

Alkyl glucosides surfactants are synthesized by a cascade process that involves the methanolysis of cellulose into methyl glucosides followed by the transacetalization with n-octanol. The first step was performed using methanol as solvent and acid catalysts (such as, inorganic acids, heteropolyacids, ionexchange resins, or modified carbon materials). Subsequently, long-chain alkyl glucosides are obtained in the second step by transacetalization, which involves the reaction of methyl glucosides with a fatty alcohol using the same acid catalyst. The overall process was performed under mild conditions. Amorphous sulfonated carbon catalyst achieved the best results for the complete conversion of cellulose in methanol at 200 °C with methyl α,β-glucopyranosides yields higher than 80 %. Moreover, this material containing -SO3 H groups is ideal to perform the second step to obtain octyl and decyl glucosides in yields higher than 73 % at 120 °C. In addition, the sulfonated carbon catalyst (C-SO3 H) can be reused with only a slightly decrease of its activity after four consecutive cycles.

X선 산란분석법을 이용한 액정에멀젼 구조분석

본 연구에서는 <TEX>$C_{12-20}$</TEX> 알킬글루코사이드, <TEX>$C_{14-22}$</TEX> 알코올 및 베헤닐알코올로 구성된 액정에멀젼을 제조하고 다양한 분석장비를 이용하여 구조분석을 실시하였다. 먼저 제조한 액정에멀젼을 편광현미경과 cryo-SEM을 이용하여 각각 액정에멀젼의 특징인 maltese cross 무늬와 다층 구조를 확인하였다. 또한, DSC를 이용하여 액정상 형성을 확인하였고, small angle x-ray scattering (SAXS) 분석을 통하여 약 <TEX>$305{\AA}$</TEX>의 층간 간격을 갖는 다층 라멜라 구조를 확인하였다. 한편, wide angle x-ray scattering (WAXS) 분석을 통해 제조된 액정에멀젼의 라멜라 구조를 이루고 있는 알킬 사슬 간 배열이 사방정계 구조로 되어 있음을 확인할 수 있었다. 액정에멀젼 구조 연구를 통해 얻어진 다양한 물성 정보는 향후 산업적으로 많이 이용될 것으로 기대된다. In this study, we prepared liquid crystal emulsions composed of <TEX>$C_{12-20}$</TEX> alkyl glucoside, <TEX>$C_{14-22}$</TEX> alcohol, and behenyl alcohol and performed structure analysis using various analytical equipment. First, as an important characteristic of liquid crystal emulsions, maltese cross patterns and multi-layer structure were observed by a polarized microscope and cryo-SEM. Also, formation of liquid crystal phase was confirmed by DSC and multi-layer lamellar structure having an interlayer spacing approximately <TEX>$305{\AA}$</TEX> was confirmed by small angle x-ray scattering (SAXS). The alkyl chain arrangement formed orthorhombic structure of a lamellar structure of the liquid crystal emulsion was confirmed by wide angle x-ray scattering (WAXS). These results suggest that information on the various physical properties obtained through the research of liquid crystal emulsion structure is expected to be widely used in cosmetics development in the future.

Synthesis of Alkyl Monoglucoside Citric Monoester and Properties of Its Sodium Salt

AbstractA series of disodium alkyl monoglucoside citric monoesters (AG‐EC) were synthesized with an indirect method using glucosides, lauryl/decyl/octyl alcohol and citric acid. The structure and composition of the synthesized surfactants were defined by Fourier transform infrared spectroscopy (FTIR) and liquid chromatography–mass spectrometry (LC/MS). The surface properties, foaming ability and wetting ability were investigated. AG‐EC surfactants exhibited excellent water solubility which eliminated the defect of long‐chain alkyl glucoside. All three surfactants showed high surface activities. AG12‐EC and AG10‐EC showed remarkable foaming abilities in distilled water and hard water. Aqueous solutions of AG‐EC surfactants spread slowly on a parafilm surface.

Relationship between liquid crystalline phase stability and ingredient composition in liquid crystal oil–water emulsion

ABSTRACTIn this study, we postulated that the optical retardation magnitude could be used to evaluate the stability of the LC phase through the Mueller matrix polarimeter method in LC emulsion. In addition, we found that the increase of cetearyl alcohol concentration induced the more periodic dense lattice structure in crystalline phase of LC lamellae and the sorbitan olivate was relatively more responsible for higher ordering in LC phase compared to C12–20 alkyl glucoside in terms of molecular parallel packing on the basis of the optical retardation magnitude. Furthermore, it was confirmed that the LC emulsion had higher skin barrier function owing to lower TEWL and higher reflectance than ordinary emulsion on human skin and maintained a uniform phase without phase separation for 8 weeks.

A mild hand cleanser, alkyl ether sulphate supplemented with alkyl ether carboxylic acid and alkyl glucoside, improves eczema on the hand and prevents the growth of Staphylococcus aureus on the skin surface.

Washing the hands using cleansers with antiseptic materials is the most popular method for hand hygiene and helps maintain health by preventing food poisoning and bacterial infections. However, repeated hand washing tends to induce eczema of the hand, such as dryness, cracking and erythema. Moreover, eczema on the hand leads to increased levels in Staphylococcus aureus (S.aureus) on the skin surface in contrast to expectations. Thus, mild hand cleansers which induce less eczema even with repeated washings are desired. Here, we evaluated the efficacy of a hand cleanser formulated with alkyl ether sulphate (AES), alkyl ether carboxylic acid (AEC) and alkyl glucoside (AG) that contains isopropyl methylphenol (IPMP) on skin symptoms and S.aureus levels. Eczema of the hand and the presence of S.aureus on the skin surface were analysed prior to and following 4weeks of usage of the hand cleanser. A soap-based hand cleanser with IPMP was used as a reference cleanser. Eczema and cutaneous conditions were evaluated by visual grading, transepidermal water loss (TEWL), stratum corneum moisture-retention ability (MRA) and skin surface pH. The repeated use of the soap-based hand cleanser significantly worsened the hand dryness, scaling and cracks on the tips of the fingers and significantly increased the TEWL and decreased the MRA. In contrast, usage of the test cleanser only induced a significant increase in skin dryness but did not induce skin scaling or cracking and did not increase TEWL or decrease the MRA. Corresponding to these changes in skin symptoms, the presence of S.aureus increased the following use of the reference cleanser but not the test cleanser. There was no significant difference in skin surface pH between the two cleansers. Moreover, the increase in S.aureus was significantly correlated to the worsening of skin dryness and scaling. These results suggest that not only antimicrobial activity but also the mildness, which minimizes cutaneous effects, are important for hand cleansers to prevent the growth of S.aureus. The cleanser formulated with AES, AEC and AG containing IPMP is mild and is effective to promote hand hygiene.

The formation of mixed micelles of sugar surfactants and phospholipids and their interactions with hyaluronan

The aggregation of sugar surfactants and the incorporation of phospholipids into sugar surfactant micelles were investigated by means of fluorescence spectroscopy. Two representatives from the family of alkyl glucosides were studied: dodecyl-β-D-maltoside and octyl-β-D-glucopyranoside. The presence of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) in the sugar surfactant system promoted the formation of new structures at sugar surfactant concentration below its critical micelle concentrations. According to the aggregation number measurements studied by a fluorescence quenching of hexadecylpyridinium chloride measurements, the premicellar aggregates formed from octyl-β-D-glucopyranoside and DPPC were composed of the third of molecules compared to the octyl-β-D-glucopyranoside micelles. Interactions of the formed mixed micelle systems composed of sugar surfactant and DPPC with hyaluronan were explored. The addition of hyaluronan had different effects on the dodecyl-β-D-maltoside/DPPC and octyl-β-D-glucopyranoside/DPPC mixed systems. In addition, the mixed system of dodecyl-β-D-maltoside and lecithin was studied, but possibly, only a coexistence of lipid aggregates and sugar surfactant micelles was observed.

Alkyl glycosides as potential anti-Candida albicans growth agents

Abstractinfections are becoming increasingly prevalent and many clinical isolates are resistant to common azole derivatives treatment. Accordingly, the capacity of a series of 19 alkyl glycosides, mainly mannosides and glucosides but also a cellobioside with aglycone chain-length from C-6 to C-20, to inhibit the growth of laboratory and clinically isolated strains of

Dispersion of Vesicles Composed of Industrially Produced Alkyl (Oligo) Glucoside Using Diol-Boron Complexation.

Alkyl (oligo)glucosides (AOG) are known to be environmentally compatible amphiphiles whose commercial applicability should be broadened. The present paper describes the preparation of molecular assemblies of industrially produced AOG, which is a mixture composed of different length of alkyl chains (C9-C12) with oligoglucoside moiety with a few (1-3) of glucose units. It was also described that regulation of the dispersibility of the molecular assemblies prepared by diol-boron complexation between the sugar moiety on AOG and boric acid in a dispersion medium. The molecular assembly of AOG was successfully formed by mixing AOG and cholesterols (CH). When using a suitable amount of CH (20-40 mol% with respect to AOG), the molecular assembly formed a vesicle structure. The dispersion ability of the resulting vesicle was dependent on both the boric acid concentration and pH of the dispersion medium. The light-scattering and ζ-potential measurements revealed that high concentrations (≥10 mM) of boric acid improved dispersibility the vesicles. In contrast, the vesicle agglomerated at low concentrations of boric acid (1-7.5 mM). In the absence of boric acid in dispersion medium, the vesicles were completely agglomerated. The optimum pH range for vesicle dispersion was found to be from neutral to basic (7.4-10.1). The (11)B NMR study revealed that borate ester formation occurred between boric acid and the diol of the sugar moiety on AOG vesicle. The present data suggest that borate ester formation that occurred on the surface of the vesicle provided negative charge to the vesicles, contributing to their dispersion via repulsive forces.

글리시리직애씨드의 경피 전달을 위한 액정 에멀젼의 제조와 물리적 특성 및 In Vitro 피부투과 연구

In this study, we prepared liquid crystal emulsion composed of amphiphilic substance C14-22 alcohol, C12-20 alkyl glucoside, behenyl alcohol and studied liquid crystal emulsion of properties and in vitro skin permeation. The results of formulation experiments, the clear liquid crystalline structure was observed in the ratio of C14-22 alcohol 0.8%, C12-20 alkyl glucoside 3.2%, behenyl alcohol 4% in the formulation. The results of physical property measurements, the viscosity of liquid crystal emulsion and O/W emulsion applied as a control group was respectively 1871.26 ∼ 1.15 Pa⋅s, 1768.69 ∼ 1.14 Pa⋅s and the shear stress of O/W emulsion was 178.68 ∼ 909.18 Pa, that of liquid crystal emulsion was 190.45 ∼ 919.38 Pa. The storage modulus of O/W emulsion was 3428.53 ∼ 9157.45 Pa, that of liquid crystal emulsion was 4487.82 ∼ 8195.59 Pa. The tan (delta) value of O/W emulsion which means a ratio of viscosity to elasticity was 0.43 ∼ 0.19, and that of liquid crystal emulsion was 0.23 ∼ 0.25. The water content value on the skin for liquid crystal emulsion was significantly higher from 1 h to 6 h compared with that of O/W emulsion and the transepidermal water loss on the skin was significantly superior in skin moisture loss suppression from 30 min to 4 h compared with that of O/W emulsion. The results of skin permeation using glycyrrhizic acid, the result of skin permeation amount of liquid crystal emulsion for 24 h was 64.58 μg/cm2, that of O/W emulsion was 37.07 μg/cm2, that of butylene glycol solution was 41.05 μg/cm2. Hourly permeability results, it is showed that skin penetration effect of the liquid crystal emulsion increases after 8 h. These results suggest that liquid crystal emulsions are effective for skin moisturizing effect and function as potential efficacy ingredient delivery system for the transdermal delivery.

Effect of heater size on ultrasonic enhancement of boiling in water and surfactant solutions

Experiments were performed to study enhancement of heat transfer from the wire of d = 50 µm and the tube of d = 1.5 mm in subcooled pool boiling by ultrasonic waves. The working fluids are clean water and Alkyl (8-16) Glucoside surfactant solutions of different concentrations and bulk temperature 30 °C. The wire resistance was translated to the temperature, using the calibration data, the temperature of the tube was measured by thermocouple. The differences between effect of ultrasonic field on boiling in water for heaters of d = 50 µm and d = 1.5 mm may be summarized as follows: for boiling on the wire of d = 50 µm in subcooled water, Tb = 30 °C, enhancement of heat transfer coefficient due to applied ultrasonic field is about 70% and 20% at heat flux q = 620 kW/m2 and q = 1350 kW/m2, respectively. For boiling in surfactant solutions at the same boiling conditions enhancement of heat transfer coefficient is in the range of 5–10% at heat flux q = 620 kW/m2 and 10–16% at heat flux q = 1350 kW/m2 depending on solution concentration. For boiling on the tube of d= 1.5 mm in subcooled water, Tb= 30 ℃, enhancement of heat transfer coefficient due to applied ultrasonic field is about 50% and 45% at heat flux q = 500 kW/m2 and q = 2500 kW/m2, respectively. The same values are obtained for boiling in surfactant solution of concentration C = 250 ppm. For the wire of d = 50 µm the heat transfer enhancement due to acoustic vibrations in surfactant solutions is not as strong as in water. This fact may be considered as evidence of significant role of relationship between jet flow and ultrasonic field.

Interfacial Activity and Oil Displacement Efficiency of an Alkyl Glucoside and Petroleum Sulfonate System

A novel binary compound flooding system was developed using the combination of nonionic surfactant alkyl glucoside and anionic surfactant petroleum sulfonate with the mass ratio of 1:1. The interfacial activity was studied by experiments. The results showed that the interfacial tension between a binary compound flooding system and crude oil was reduced to an ultra-low value at 45–80°C, and the compounded system showed good tolerance to salt and divalent cations. Core flooding experiment results showed that the system could further improve recovery after water flooding. Micro-flooding experiment results showed that the system could further start and displace residual oil after polymer flooding.

Isobornyl acrylate: an impurity in alkyl glucosides

Context: Alkyl glucosides and alkyl poly-glucosides are widely used as wetting agents, surfactants and emulsifiers in several industrial and cosmetic products. They are known as well-tolerated and are usually added to the primary surfactants in order to reduce the irritating potential of the main foaming agents.Objective: Recently, some authors suggested that allergic contact dermatitis to alkyl glucosides might be more frequent than suspected. On the other hand, the chemical structures of glucosides do not show potentially allergenic chemical groups or strongly polarized structures. The aim of our study is to investigate alkyl glucosides carrying out a detailed chemical analysis on samples of raw materials to identify potentially allergenic impurities or by-products contained in commercial samples of alkyl glucosides.Materials and methods: We chemically analyzed samples of cocoyl glucoside, decyl glucoside and lauryl glucoside by three different analytical methods, in order to identify any undesired or polluting substances.Result: In each of the three samples, we detected the presence of isobornyl acrylate. Its approximate content in the tested samples is 500 ng/g of the product.Discussion: Isobornyl acrylate is not used in the synthesis of alkyl glucosides, but as a plasticizer in many plastic materials. It can be easily released to materials flowing over these surfaces when they have high extraction power, as glucosides.Conclusion: Isobornyl acrylate may play a role as hidden allergen, in the form of an impurity collected during the industrial process, explaining some cases of allergic reaction to alkyl glucosides.

Gene clone and characterization of a novel thermostable β-galactosidase with transglycosylation activity from Thermotoga naphthophila RUK-10

We cloned and expressed a new recombinant β-galactosidase(TN0949) from Thermotoga naphthophila RKU-10 with the pET28a(+) vector system in Escherichia coli BL21(DE3), and determined its catalytic capability to synthesize alkyl glucosides. The recombinant enzyme was purified to a single band via heat treatment and Ni2+-NTA affinity chromatography. The molecular mass of the recombinant enzyme was estimated to be 79 kDa with sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE). TN0949 can hydrolyze o-nitrophenyl β-D-galactopyranoside at the optimum pH and temperature of 6.5 and 80 °C, respectively. TN0949 can also hydrolyze lactose at the optimum pH and temperature of 5.2 and 80 °C, respectively. The Km values for the hydrolyses of o-nitrophenyl β-D-galactopyranoside and lactose were 0.82 and 83.65 mmol/L, respectively. TN0949 was stable over a wide range of pH(3.0 to 7.0) after 24 h of incubation. The half-lives of TN0949 at 75, 80 and 85 °C were 22, 6 and 1.33 h, respectively. The enzyme displayed the capability to use lactose as the transglycosylation substrate to synthesize butyl galactopyranoside and hexyl galactopyranoside, indicating its suitability as a candidate industrial biocatalyst.