Studies on absorption and hydrolysis of ethyl alpha-D-glucoside in rat intestine

Ambient 1,2-propanediol exposure accelerates the degradation of lipids and amino acids in milk via allosteric effects and affects the utilization of nutrients containing amide bond

The scandal of detecting 1, 2-propanediol (PL) in milk brought a crisis to the trust of consumers in the dairy industry, and the potential toxicity of PL has aroused the public concern about dietary exposure. A total of 200 pasteurized milk samples were collected from 15 regions, and the quantity of PL ranged between 0 and 0.31 g kg^-1. Pseudo-targeted quantitative metabolomics integrated with proteomics demonstrated that PL enhanced the reduction of κ-casein, β-casein, and 107 substances (41 amines and 66 amides) containing amide bonds. Pathway enrichment and topological analysis indicated that PL induced the metabolism of lipids, amino acids, oligosaccharide nucleotides, and alkaloids by accelerating the rate of nucleophilic reaction, and acetylcholinesterase, sarcosine oxidase, and prolyl 4-hydroxylase were determined as the vital enzymes related to the degradation of above nutrients. The results of molecular simulation calculation illustrated that the number of hydrogen bonds between acetylcholinesterase, sarcosine oxidase, and substrate increased to 2 and 3, respectively, while the position of hydrogen bonds between prolyl 4-hydroxylase and proline was shifted, indicating the change of conformation and the enhancement of hydrogen bond force were essential factors for the up-regulation of enzyme activity. This study first revealed the mechanism of deposition and transformation of PL in milk, which contributed to the knowledge of the quality control of milk and provided vital indicators to evaluate the adverse risks of PL in dairy products.

A validated method for the separation of ethyl glucoside isomers by gas chromatography-tandem mass spectrometry and quantitation in human whole blood and urine

Ethyl glucoside (EG) is present in Japanese sake in high concentrations, and can be found in other alcoholic beverages like beer and wine in varying amounts. EG exists as alpha (α) and beta (β) isomers, and the concentrations and ratios of these isomers differ depending on the alcoholic beverage. Herein, we report a validated analysis method for the separation of EG isomers in human whole blood and urine, by GC-MS/MS. Whole blood and urine samples were deproteinized and interferences removed by weak cation exchange cartridges. The target analytes were acetylated using acetic anhydride and pyridine by microwave-accelerated derivatization. Separation was performed using tandem columns, with detection in the multiple reaction monitoring (MRM) mode. The MRM transitions for all compounds were m/z 157.0 > 115.1 for the quantifying transition, and m/z 157.0 > 73.1 and m/z 141.0 > 81.0 for the qualifying transitions. Assay validation included linearity, LOD and LLOQ, bias, within-run and between-run precision, stability, and dilution integrity. Baseline separation of the 2 isomers was achieved with linear calibration (r² > 0.99) across the calibration range 0.625 to 50 μg/mL for both α- and β-EG in both whole blood and urine. The validated method was then applied to actual human whole blood and urine samples collected at autopsy, as well as relevant alcoholic beverage samples. The quantitation of EG isomers could benefit the forensic toxicology community by acting as markers for recent alcoholic beverage consumption.

Effects of ethyl-α-d-glucoside on human dermal fibroblasts

Ethyl α-d-glucoside (α-EG) is a glycoside present in sake, Japanese rice wine. Previous studies have reported that α-EG suppresses skin roughness after ultraviolet B irradiation, transepidermal water loss, and hepatic function disorder, and has a skin moisturizing effect. In this study, 0.48 μM of α-EG was found to increase the proliferation of normal human dermal fibroblasts (NHDF) by 121.0%, and the amount of collagen I produced by NHDF increased by 159.6% at an α-EG concentration of 0.048 μM, compared to those in cells cultured without α-EG. In NHDF cultured in α-EG-supplemented medium, the expression of fibroblast growth factor I and VII mRNA increased by 148.8 and 153.1%, at an α-EG concentration of 4.8 and 0.048 μM, respectively, as measured by a quantitative reverse transcription-polymerase chain reaction. Transcript levels of type I collagen genes, COL1A1 and COL1A2, increased by 152.4 and 129.7%, respectively, and that of a type III collagen gene, COL3A1, increased by 131.8% at an α-EG concentration of 0.48 μM. These findings supported the possibility that α-EG was involved in the maintenance and improvement of skin homeostasis and moisturizing functions.

Phlorhizin protects against erythrocyte cell membrane scrambling

Phlorhizin interferes with glucose transport. Glucose depletion triggers suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling. Eryptosis is further triggered by oxidative stress. The present study explored whether phlorhizin influences eryptosis following glucose depletion or oxidative stress. Cell membrane scrambling was estimated from annexin binding, cell volume from forward scatter (FSC), and cytosolic Ca(2+) concentration from Fluo-3 fluorescence. Phlorhizin (10-100 μM) added alone did not modify scrambling, FSC, or Fluo-3 fluorescence. Glucose depletion (48 h) significantly increased Fluo-3 fluorescence, decreased FSC, and increased annexin binding, effects in part significantly blunted by phlorhizin (annexin binding ≥ 10 μM, FSC ≥ 50 μM). Oxidative stress (30 min 0.3 mM tert-butylhydroperoxide) again significantly increased Fluo-3 fluorescence and triggered annexin binding, effects again in part significantly blunted by phlorhizin (Fluo-3 fluorescence ≥ 50 μM, annexin-binding ≥ 10 μM). Phlorhizin did not blunt the cell shrinkage induced by oxidative stress. The present observations disclose a novel effect of phlorhizin, that is, an influence on suicidal erythrocyte death following energy depletion and oxidative stress.

Effect of a sake concentrate on the epidermis of aged mice and confirmation of ethyl alpha-D-glucoside as its active component

Generations of Japanese have appreciated the positive effects that sake can have on skin conditions, and studies have shown that concentrated sake suppressed the epidermal barrier disruption caused by ultraviolet B (UVB) irradiation. We investigated the effect of a topical application of a sake concentrate on the murine epidermis and found that the intercellular lipid content in an aged epidermis was significantly increased. Furthermore, the topical application of ethyl alpha-D-glucoside (alpha-EG), a component of sake, brought about a similar improvement in the levels of intercellular lipids. Following on from this, we confirmed that alpha-EG also significantly increased the content of loricrin protein, an indicator of successful corneocyte differentiation, while reducing the number of corneocyte layers in the aged stratum corneum. These results confirmed alpha-EG as the primary active component of the sake concentrate that had a positive effect on the epidermis. alpha-EG increased the intercellular lipid content, accelerated the differentiation of corneocytes, and reduced the thickness, thus improving the functions of the stratum corneum.