• Preventive Nutrition and Food Science
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• v.14 no.1
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• pp.8-13
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• 2009

This study investigated the hypoglycemic effect of fermented soymilk extract (FSE) in STZ-induced diabetic mice. FSE was prepared via fermentation of soymilk with Bacillus subtilis followed by methanol extraction. The hypoglycemic effect was determined by inhibitory activities against ${\alpha}$-glucosidase and ${\alpha}$-amylase as well as the alleviation of postprandial glucose level. The non-fermented soymilk extract (SE) was used as control in this experiment. FSE showed higher (p<0.05) inhibitory activities than SE against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The $IC_{50}$ values of FSE for ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.77 ancd 0.94 mg/mL, respectively, which were comparable or even superior to those of acarbose (0.79 and 0.68 mg/mL, respectively). In addition, a further suppression on the postprandial blood glucose levels were observed in the FSE than SE group for both STZ-induced diabetic mice and normal mice. Furthermore, FSE significantly lowered the incremental area under the curve (AUC) in the diabetic mice and the AUC in normal mice corroborated the hypoglycemic effect of FSE (p<0.05). Results from this study suggest that FSE may help decrease the postprandial blood glucose level via inhibiting ${\alpha}$-glucosidase and ${\alpha}$-amylase and the usefulness of FSE was proven to be better than SE.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.7-13
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• 2010

We investigated whether the fermented soymilk extract (FSE) has protective effects against high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). FSE was prepared via fermentation of soymilk with Bacillus subtilis followed by methanol extraction. To determine the protective effect of FSE, oxidative stress was induced by exposing of HUVECs to the high glucose (30 mM) for 48 hr. Exposure of HUVECs to high glucose for 48 hr resulted in a significant (p<0.05) decrease in cell viability, catalase, SOD and GSH-px activity and a significant (p<0.05) increase in intracellular ROS level and thiobarbituric acid reactive substances (TBARS) formation in comparison to the cells treated with 5.5 mM glucose. However, at concentration of 0.1 mg/mL, FSE treatment decreased intracellular ROS level and TBARS formation, and increased cell viability and activities of antioxidant enzymes including catalase, SOD and GSH-px in high glucose pretreated HUVEC. These results suggest that FSE may be able to protect HUVECs from high glucose-induced oxidative stress, partially through the antioxidative defense systems.