Polysiphonia japonica Extract Attenuates Palmitate-Induced Toxicity and Enhances Insulin Secretion in Pancreatic Beta-Cells.

Beta-cell loss is a major cause of the pathogenesis of diabetes. Elevated levels of free fatty acids may contribute to the loss of ß-cells. Using a transgenic zebrafish, we screened ~50 seaweed crude extracts to identify materials that protect ß-cells from free fatty acid damage. We found that an extract of the red seaweed Polysiphonia japonica (PJE) had a ß-cell protective effect. We examined the protective effect of PJE on palmitate-induced damage in ß-cells. PJE was found to preserve cell viability and glucose-induced insulin secretion in a pancreatic ß-cell line, Ins-1, treated with palmitate. Additionally, PJE prevented palmitate-induced insulin secretion dysfunction in zebrafish embryos and mouse primary islets and improved insulin secretion in ß-cells against palmitate treatment. These findings suggest that PJE protects pancreatic ß-cells from palmitate-induced damage. PJE may be a potential therapeutic functional food for diabetes.