Caulerpa lentillifera inhibits protein-tyrosine phosphatase 1B and protects pancreatic beta cell via its insulin mimetic effect.

The aim of this study was to determine whether Caulerpa lentillifea extract (CLE) can protect pancreatic beta cells and enhance insulin signaling in adipocytes. We measured the protein tyrosine phosphatase (PTP)-1B inhibitory effect of CLE using an in-vitro enzyme assay. Proteins involved in the pancreatic beta-cell death and insulin signaling were measured by western blotting. Oil-red O staining was used to measure the insulin mimetic effect of CLE. CLE strongly inhibited the PTP1B enzyme. In rat insulinoma (RIN)-m5F cells, CLE decreased the activation of extracellular regulated kinase (ERK)-1/2, P38 mitogen activated protein kinase (P38), c-Jun NH2-terminal kinase (JNK), and nuclear factor kappa-light-chain-enhancer of the activated B cells (NF-κB). Furthermore, CLE showed insulin-mimetic effect and enhanced the activation of insulin-signaling molecules including IRS, AKT, PI3K, and GSK-3β in 3T3-L1 adipocytes. Our results suggested that CLE-inhibited PTP1B, protected the pancreatic beta cells, and enhanced insulin sensitization in the adipocytes.