Antidiabetic activity of angelan isolated from Angelica gigas Nakai.

Angelan isolated from Angelica gigas Nakai inhibits tumor growth and metastasis by enhancing immune functions of macrophages, dendritic cells, and B cells. Here, we report that angelan can inhibit autoimmunity in non-obese diabetic (NOD) mice. Although 80% of the NOD mice had developed diabetes by 24 weeks of age, none of the angelan-treated NOD mice developed diabetes. The mean glucose levels were 118 mg/dl in angelan-treated mice and 506 mg/dl in control NOD mice. Histological examination of the pancreatic islets revealed that most of the islets isolated from angelan-treated mice were less infiltrated with lymphocytes compared with those of control mice. Spleen cells from diabetic NOD mice could adaptively transfer diabetes into NOD. scid mice, but those from angelan-treated NOD mice did not, suggesting that angelan caused the spleen cells to lose the ability to destroy beta cells. However, angelan did not affect cytokine production of spleen cells. These results suggest that angelan has dual immunomodulatory functions, i.e., immunostimulation in tumor-bearing mice and immunosuppression in autoimmune diabetic mice.