Preparation of a Momordica charantia L. polysaccharide‑chromium (III) complex and its anti-hyperglycemic activity in mice with streptozotocin-induced diabetes.

Polysaccharides comprise the major bioactive components in Momordica charantia L. We here synthesized and characterized a novel M. charantia polysaccharide‑chromium (III) complex (MCPIIaC) and assessed its anti-diabetic effects in mice with streptozotocin (STZ)-induced diabetes mellitus (DM) and its mechanism underlying hypoglycemia. MCPIIaC is a novel polysaccharide‑chromium (III) complex containing 14.68% elemental chromium. A Fourier transform infrared (FTIR) spectrogram experiment showed that the chromium ions are linked to the polysaccharide's hydroxyl groups. Combined circular dichroism (CD) and atomic force microscopy (AFM) analyses indicated that after linking with chromium ions, the flexibility of the three-dimensional structure of the polysaccharide increased. After the treatment of MCPIIaC for four weeks, the mice with STZ-induced DM exhibited significantly lower fasting blood glucose levels and body weight, whereas higher insulin levels and antioxidant enzyme activity than in the diabetic group. Optimal effects were obtained with a dosage of 30 mg MCPIIaC/kg body weight. Histological analysis indicated that MCPIIaC alleviated the oxidative tissue damage in STZ-lesioned mice. An acute toxicity experiment indicated that MCPIIaC was safe at a dose of 1500 mg/kg. These results suggest that MCPIIaC might be an excellent candidate hypoglycemic agent for the prevention of diabetes.