Comparison of 1-Deoxynojirimycin and Aqueous Mulberry Leaf Extract with Emphasis on Postprandial Hypoglycemic Effects: In Vivo and in Vitro Studies

• Published in: Journal of agricultural and food chemistry Vol. 59; no. 7; pp. 3014 - 3019
• Main Authors: Kwon, Hye jin, Chung, Ji Young, Kim, Ji Yeon, Kwon, Oran
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Washington, DC American Chemical Society 13.04.2011
• Subjects: 1-Deoxynojirimycin - administration & dosage; alpha-glucosidase; Animals; Bioactive Constituents; Biological and medical sciences; blood glucose; Blood Glucose - drug effects; Blood Glucose - metabolism; Caco-2 Cells; Deoxyglucose - metabolism; deoxynojirimycin; digestion; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; glucose; glucose transporters; glycemic effect; human cell lines; Humans; hyperglycemia; Hypoglycemic Agents; Intestinal Absorption - drug effects; leaf extracts; Male; microvilli; Morus - chemistry; phytochemicals; Plant Extracts - administration & dosage; Plant Leaves - chemistry; Rats; Rats, Sprague-Dawley; 1-deoxynojirimycin; maltose digestion; glucose absorption; mulberry leaf extract; pretreatment; Mulberry; Fruit; deoxynojirimycin; Postprandial; Extract; Plant leaf; Digestion; Glucose; Maltose; In vitro; In vivo; Alkaloid; Hypoglycemic agent; Absorption; Plant part; Carbohydrate; Comparative study
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf103463f

Carbohydrate digestion by α-glucosidase and subsequent glucose uptake at the brush border are critical for postprandial blood glucose control. Any specific inhibitors are useful as hyperglycemia modulating agents. In this study, it was postulated that an array of active components in mulberry leaf extract (MLE) may provide higher potency in inhibiting intestinal glucose absorption compared to the single component 1-deoxynojirimycin (DNJ), which is recognized as a promising inhibitor of intestinal glucose absorption. Both MLE and DNJ were active in inhibiting α-glucosidase. However, in Caco-2 cells, only MLE showed significant inhibition of 2-deoxyglucose uptake, whereas DNJ was ineffective. For glucose loading, co-administration of MLE resulted in potent inhibitions of glucose responses compared to those by DNJ in Sprague Dawley (SD) rats, but this was not found for maltose loading. These novel findings add evidence that the unabsorbed phytochemicals in MLE compete with glucose for intestinal glucose transporters, but DNJ itself does not. We also evaluated the timing of MLE consumption. By administering MLE for 30 min before glucose loading, the incremental area under the curve (IAUC) was significantly lowered in the rats, as compared to a simultaneously administered group. Similarly, cellular glucose uptake was significantly reduced in Caco-2 cells following pretreatment.