Refined linkage analysis of the sulphated marine polysaccharide fucoidan of Cladosiphon okamuranus with a focus on fucose.

Methylation followed by depolymerization and gas chromatography (GC) is an effective methodology for the linkage analysis of polysaccharides, including fucoidan, a sulphated algal polysaccharide. However, this sample material demands attention to experimental details to prevent aberrations in the analytical result. The use of deficient bases for methylation, the presence of water, analyte degradation during hydrolysis, and coelution of the target analytes during gas chromatography create doubts about published results. We therefore investigated critical parameters of the method and carefully optimized the steps of the protocol to ensure the integrity of the results for the fucose monomers. Fucoidan from Cladosiphon okamuranus was used as reference sample to determine the glycosidic bonds, and sulphate positions in the monomer. Fucoidan in protonated form was methylated in a strictly water-free environment using lithium dimsyl as base and methyl iodide for methylation. The methylated polymer was isolated by solid phase extraction, which was crucial to recover also the highly sulfated fraction. Hydrolysis was conducted with trifluoroacetic acid. To separate all target analytes in GC-FID/MS, a stationary phase with high cyanopropyl content (HP-88) was required, as the commonly employed phenyl siloxane phases result in co-elution, which distorts the result severely.

Topical Administration Effect of Sargassum duplicatum and Garcinia mangostana Extracts Combination on Open Wound Healing Process in Diabetic Mice.

This research aimed to determine the topical administration effect of the combination of Sargassum duplicatum and Garcinia mangostana extracts to ameliorate diabetic open wound healing. The study used 24 adult males of Mus musculus (BALB/c strain, 3-4 months, 30-40 g). They were divided into normal control groups (KN) and diabetic groups. The diabetic group was streptozotocin-induced and divided further into three treatment groups: the diabetic control group (KD), the S. duplicatum treatment group (PA), and the combination of S. duplicatum and G. mangostana treatment group (PAM). The dose of treatment was 50 mg/kg of body weight. Each group was divided into three treatment durations, which were 3 days, 7 days, and 14 days. The wound healing process was determined by wound width, the number of neutrophils, macrophages, fibroblasts, fibrocytes, and collagen density. Histological observation showed that the topical administration of combination extracts increased the re-epithelialization of the wounded area, fibroblasts, fibrocytes, and collagen synthesis. The topical administration of combination extracts also decreased the number of neutrophils and macrophages. This study concluded that the topical administration of the combination of S. duplicatum and G. mangostana extracts improved the open wound healing process in diabetic mice.

Identification of a novel umami peptide in tempeh (Indonesian fermented soybean) and its binding mechanism to the umami receptor T1R.

Tempeh, a traditional Indonesian soybean product produced by fermentation, is especially popular because of its umami taste. In this study, a novel umami peptide GENEEEDSGAIVTVK (GK-15) was identified in the small peptide (<3 kDa) fraction of the water extract of tempeh using LC-MS/MS analysis and database-assisted identification. The umami taste of GK-15 was further validated using sensory evaluation, which suggested that GK-15 may be one of the key components contributing to the umami taste in tempeh. To rationalize the biological effect of GK-15, molecular docking of GK-15 into the N-terminal extracellular ligand-binding domain of the umami (T1R) receptor was performed. ZDOCK data showed that GK-15 could perfectly bind either to the open or closed conformation of T1R3. To the best of our knowledge, the present work is the first study to focus on the screening of umami peptides from tempeh.