Based on the traditional Chinese medicine formula, two fractions, namely Fr.A and Fr.B, are obtained from the extract of both astragalus and glycyrrhiza as starting materials through water decoction process, ethanol precipitation, organic solvent extraction and macroporous adsorption resin separation. Fr.A is 45-55wt% polysaccharide and Fr.B contains 25-40wt% saponins and 35-50wt% flavonoids. By combining Fr.A with Fr.B, the extract-composition of traditional Chinese herbal medicine for preventing and treating diabetes is gained, and the effective substance is definite and the mechanism is clear.

The cell glucose consumption experiment in vitro shows that the extract-composition can promote the glucose consumption of HePG2 which is similar to phenotype of human hepatocyte cell. The animal experiment in vivo demonstrates that the extract-composition can significantly lower blood sugar of alloxan-induced hyperglycemia rats, increase the absorption of glucose by stem cells, promote the synthesis of liver starch, regulate blood lipid disorder and improve lesions of pancreas and liver. It is found that the sugar reducing effect of the extract-composition is better than the drug made by the original formula and the respective fraction.

The work was supported by the National Natural Science Foundation of China (NSFC 20475057).

Background information:

Diabetes mellitus, often simply referred to as diabetes—is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger).

Diabetes has become the third leading killer only after malignant tumour and cardiovascular disease. Traditional Chinese medicine has obvious advantage in preventing and treating diabetes and its chronic complications.