Hepatoprotective Effect of Fresh Grape Juice Prepared by a Low-Speed Masticating Juicer in db/db Mice.

This study investigated the hepatoprotective effect of fresh grape juice prepared using a low-speed masticating (LSM) juicer or a high-speed centrifugal (HSC) juicer in mice. Six-week-old db/db mice were fed on an AIN-93G diet or a diet containing 1% freeze-dried LSM or HSC grape juice for 7 weeks. Treatment with LSM grape juice significantly decreased hepatic triglycerides, serum aspartate transaminase activities, and homeostasis model assessment for insulin resistance values, whereas HSC juice did not significantly influence these parameters. The LSM grape juice showed higher antioxidant and anti-inflammatory activities than HSC juice. The benefits of LSM grape juice are probably due to a much higher proanthocyanidin content than that of HSC juice. These results suggest that LSM grape juice can exert hepatoprotective effects in db/db mice, partly through improving insulin resistance and promoting antioxidant and inflammatory activities.

Autumn olive (Elaeagnus umbellata Thunb.) berry reduces fasting and postprandial glucose levels in mice.

BACKGROUND/OBJECTIVES: Fasting and postprandial hyperglycemia should be controlled to avoid complications of diabetes mellitus. This study investigated the effects of autumn olive (Elaeagnus umbellata Thunb.) berry (AOB) on fasting and postprandial hyperglycemia in mice. MATERIALS/METHODS: In vitro α-glucosidase inhibitory effect of AOB was determined. Maltose solution (2 g/kg) with and without AOB extract at 500 mg/kg or acarbose at 50 mg/kg was orally administered to normal mice after overnight fasting and glucose levels were measured. To study the effects of chronic consumption of AOB, db/db mice received the basal diet or a diet containing AOB extract at 0.4% or 0.8%, or acarbose at 0.04% for 7 weeks. Blood glycated hemoglobin and serum glucose and insulin levels were measured. Expression of adiponectin protein in epididymal white adipose tissue was determined by Western blotting. RESULTS: In vitro inhibitory effect of AOB extract on α-glucosidase was 92% as strong as that of acarbose. The AOB extract (500 mg/kg) or acarbose (50 mg/kg) significantly suppressed the postprandial rise of blood glucose after maltose challenge and the area under the glycemic response curve in normal mice. The AOB extract at 0.4% or 0.8% of diet or acarbose at 0.04% of diet significantly lowered levels of serum glucose and blood glycated hemoglobin and homeostasis model assessment for insulin resistance values in db/db mice. The expression of adiponectin protein in adipose tissue was significantly elevated by the consumption of AOB at 0.8% of diet. CONCLUSIONS: Autumn olive (E. umbellata Thunb.) berry may reduce postprandial hyperglycemia by inhibiting α-glucosidase in normal mice. Chronic consumption of AOB may alleviate fasting hyperglycemia in db/db mice partly by inhibiting α-glucosidase and upregulating adiponectin expression.