Abstract: This paper was performed on hyperglycemia Lowering effect of a purified fraction of Soybean Isoflavone(SI-Ⅱ)in diabetic mice. The results showed that after intake of SI-Ⅱ for 12d at adose level of 50～100 mg/(kg•d) continuously, thehyperglycemic mice induced by Alloxan lowered the fasting blood sugar level significantly (p<0.01) as compared with the controls.SI-Ⅱ could enhance insulin concentration of alloxan-inducing diabetes mice significantly (p<0.01) and improve the cardinal symptomsof diabetes mice, such as water-intake, food-intake, protein expression and body weight. SI -Ⅱ could restore the injury of alloxan-inducedpancreas islet observed by histopathological section. The immunohistochemical result indicated that SI -Ⅱ was capable to inhibit theexpression of Fas by pancreas islet. The results also showed that SI-Ⅱ could increase the immune organ weight in alloxan-inducingdiabetes mice remarkably (p<0.01). Meanwhile, SI-Ⅱ could not affect the blood sugar level of normal mice. The studies implied thatrecovering the alloxan-induced β cell damage via the way of inhibiting the apoptosis of the beta cells of pancreas islet and enhancingimmune function might be of the important hyperglycemia lowering mechanism of SI.

Key words: soybean isoflavone, mice, hyperglycemia lowering mechanism, apoptosis, gene expression