Oral ingestion of Shiikuwasha extract suppresses diabetes progression in db/db mice by preserving ß-cell mass.

Introduction: Nobiletin is a polymethoxyflavonoid abundant in citrus peels and has been reported to have various bioactive effects. We have previously reported that nobiletin inhibits endoplasmic reticulum stress-induced apoptosis in the pancreatic ß-cell line INS-1 and that continuous subcutaneous administration of nobiletin suppresses the progression of diabetes by protecting ß-cells in type 2 diabetic db/db mice. In the present study, we investigated effects of oral ingestion of Shiikuwasha extract rich in nobiletin on the pathogenesis of type 2 diabetes in db/db mice. Materials and methods: A Shiikuwasha extract was dissolved in MediDrop sucralose. Twenty-four mice were equally divided in three groups and fed with vehicle or low or high dose of Shiikuwasha extract for 4 weeks. Blood glucose levels, pancreatic ß-cell mass, serum insulin levels, pancreatic insulin content, and other biomarkers were measured and compared between the groups. Results: The group that freely ingested the Shiikuwasha extract containing higher concentration of nobiletin (Shiikuwasha H) showed lower blood glucose levels. At the end of the experiment, the Shiikuwasha H group exhibited improved glucose tolerance, lower serum glycoalbumin levels, and an increase in ß-cell area per pancreas compared with the control group. Body weight, food intake, and serum biomarkers related to liver function and lipid metabolism of the Shiikuwasha H group were not different from those of the control group, although water intake of the former was significantly decreased than that of the latter. Conclusion: Our results suggest that the oral ingestion of Shiikuwasha extract preserves pancreatic ß-cell mass in diabetic mice, which might be attributed to ameliorating the progression of diabetes.

Surface Morphology of Cosmetic Film Consisting of PEG-Diisostearate Amphiphilic Random Copolymer, Xanthan Gum, and Solvents.

The surface morphology of a cosmetic film consisting of an amphiphilic random copolymer (methoxy polyethylene glycol-23 methacrylate/glyceryl diisostearate methacrylate copolymer, MPM-GDM) and solvents has been studied. The cosmetic film was prepared through the evaporation of water from a homogeneous aqueous mixture of MPM-GDM, xanthan gum, and solvents. MPM-GDM was soluble in water, monohydric alcohols, and 1,3-butylene glycol (1,3-BG), whereas it hardly dissolved in glycerin. The surface morphology was examined by changing the solvent composition of 1,3-BG (good solvent) and glycerin (poor solvent). Confocal laser scanning microscopy (CLSM) images of the cosmetic film showed that MPM-GDM spread through the whole film in the absence of glycerin, whereas the addition of glycerin led to the formation of a sea-island structure. It was assumed that the size of the MPM-GDM domain was determined by the balance between two factors: the miscibility (or the interfacial tension) of MPM-GDM against the solvents and the viscosity of the continuous phase. We also demonstrated that the concentration of both MPM-GDM and xanthan gum affected the surface morphology. Control of the surface morphology by changing the solubility of MPM-GDM is expected to be useful for improving the functionality and feel of cosmetic films.

Characterization of O/W Emulsions Prepared by PEG-Diisostearate Amphiphilic Random Copolymer.

We have characterized an emulsion system stabilized by an amphiphilic random copolymer, methoxy polyethylene glycol-23 methacrylate/glyceryl diisostearate methacrylate copolymer (MPM-GDM). The combined results of the static surface tension and transmission electron microscopy with freeze-fracture technique (FF-TEM) suggested that this copolymer forms aggregates in aqueous solutions. The membrane emulsification method produced an oil-in-water (O/W) emulsion in the mixture of squalane, water, and MPM-GDM, where the squalane concentration was set at 10 - 60 wt% and the MPM-GDM concentration was either 1 or 5 wt%. The prepared emulsion was stable against coalescence due to the formation of an adsorption layer of MPM-GDM. Based on the FF-TEM results, it is confirmed that a relatively large island-like structure is formed on the emulsion droplet surface. Furthermore, MPM-GDM can act as a thickening agent of the continuous liquid phase, which enhances the stability against creaming. The cooperative two effects improve the stability of the emulsion system without adding co-stabilizer such as low molecularweight surfactants.