The ion balance of Shotokuseki extract promotes filaggrin fragmentation and increases amino acid production and pyrrolidone carboxylic acid content in three-dimensional cultured human epidermis

Natural moisturizing factor(NMF)in the stratum corneum contributes to the retention of moisture there.The purpose of this study was to determine the penetration of ions in Shotokuseki extract(SE)into the three-dimensional cultured epidermis and the effect of NMF on the biosynthesis of amino acids and pyrrolidone carboxylic acid formation.Vari-ous ions,amino acids and pyrrolidone carboxylic acid were quantified by inductively coupled plasma mass spectrom-etry,fully automatic amino acid analyzer or high-performance liquid chromatography(HPLC)in three-dimensional cultured epidermis after application of SE.Gene expression levels of profilaggrin,calpain1,caspase14,and bleomycin hydrolase,which are involved in NMF production,were determined by reverse-transcription qPCR and bleomycin hydrolase activity was determined by aminopeptidase assay.The application of SE increased Na,K,Mg,Ca,Al,and Fe levels in three-dimensional cultured epidermis.The mRNA levels of the starting material of amino acid synthesis profilaggrin,and calpain1 and bleomycin hydrolase,which are involved in its fragmentation,increased.The activity of bleomycin hydrolase also increased.Furthermore,the levels of amino acids and pyrrolidone carboxylic acid increased in the three-dimensional cultured epidermis.This suggests that the ionic composition of SE may be involved in its moisturizing effect on the stratum corneum.

Red algae-derived isofloridoside activates the sweet taste receptor T1R2/T1R3

Isofloridoside (IF) is a naturally occurring galactosylglycerol compound with a refreshing sweet taste. It is found in red algae, where it acts as a photosynthetic intermediate. However, the mechanism by which IF elicits sweetness has not been determined. In this study, we investigate the interaction between IF and the sweet taste receptor T1R2/T1R3. We show that IF causes an increase in intracellular Ca2+ concentration and an increase in Erk phosphorylation in T1R2/T1R3-expressing HEK293T cells, indicating that IF interacts with T1R2/T1R3. IF also activates endogenously expressed T1R2/T1R3 in mouse small intestinal endocrine L-cells, and promotes the secretion of the incretin glucagon-like peptide-1 (GLP-1). In silico docking simulations of IF and T1R2/T1R3 predict that IF forms hydrogen bonds with Tyr103 in the extracellular Venus flytrap domain of T1R2. This result is consistent with the binding mode of many other sweet-tasting molecules. We found that IF have the potential as a new alternative sweetener.