Protective effect of cirsimaritin against streptozotocin-induced apoptosis in pancreatic beta cells

Objectives: Maintaining glucose homoeostasis is essential for the survival of cells. Despite the various health benefits of Korean thistle (Cirsium japonicum var. maackii), their effects on pancreatic β-cell apoptosis in type 1 diabetes mellitus and the underlying mechanisms remain unclear, and experimentally investigated in this study. Methods: The effects of C. japonicum var. maackii and its active component cirsimaritin against streptozotocin (STZ)-induced cytotoxicity were assessed in INS-1 cells. By Western blotting analysis, protein expressions related to apoptosis were evaluated. The involvement of apoptosis was also confirmed with image-based cytometric assay and caspase activity tests. Key findings: Cirsium japonicum var. maackii extract and cirsimaritin in non-toxic concentrations improved cell viability to near normal levels and protected INS-1 cells against STZ-induced damage. In addition, cirsimaritin reduced the intracellular oxidative stress induced by STZ. Cirsimaritin effectively suppressed apoptosis in pancreatic β cells by decreasing the activation of caspase-8 and caspase-3, BID and the DNA repair protein poly (ADP-ribose) polymerase (PARP) and increasing anti-apoptotic BCL-2 protein expression. Conclusions: This study demonstrates the therapeutic potential and action mechanism of cirsimaritin for the prevention and treatment of type 1 diabetes mellitus.