Preparation of a hydrolyzed yeast β-glucan chromium(III) complex and evaluation of its hypoglycemic activity and sub-acute toxicity.

Yeast β-glucan (BYG) possesses extremely low solubility that has limited its applications. In this study, we hydrolyzed BYG using snail enzyme to obtain hydrolyzed yeast β-glucan (HBYG) with desirable water solubility and hypoglycemic activity. On the basis of HBYG, HBYG‑chromium(III) complex (HBYG-Cr) was synthesized. The molecular weight of the complex was 4.41 × 10 Da, and the content of trivalent chromium was 8.95 %. The hydroxyl groups of HBYG participated in the coordination and formed the chromium complex. The space conformations of HBYG exhibited remarkable changes after complex formation. HBYG-Cr existed mainly in an amorphous state and presented good dispersibility, and the surface was uneven. The hypoglycemic activity of HBYG-Cr was studied in db/db and C57 mice. The results showed that HBYG-Cr had good hypoglycemic activity. Histopathological studies demonstrated that the liver, kidney, pancreas, and skeletal muscle in the treatment group were significantly improved compared with those in the diabetic model group. The sub-acute toxicity of HBYG-Cr was studied in KM mice and the results indicated that the complex did not cause adverse reactions or toxic side effects. This study broadened the application of yeast β-glucan and provided an important reference for the development of hypoglycemic functional foods and drugs.