title: Inhibitory effects of mulberry leaf extract on postprandial hyperglycemia in normal rats.
abstract: We examined the inhibitory effects of aqueous ethanol extract from mulberry leaves (ME) on postprandial hyperglycemia in normal Wistar rats. ME dose-dependently suppressed the postprandial rise of blood glucose in rats, when ME (0.02-0.5 g/kg) was given 0.5 h before the administration of carbohydrates such as sucrose, maltose and starch. The ME dose showing 50% inhibition of the increment of blood glucose (ED50) was 0.11 g/kg for sucrose, 0.44 g/kg for maltose, and 0.38 g/kg for starch. ME and its basic fraction (MB) containing 1-deoxynojirimycin were assayed for their inhibitory effects (IC50) on disaccharidase derived from the small intestine of rats. The IC50 value of ME was 3.2 microg/mL for sucrase, 10 microg/mL for isomaltase, and 51 microg/mL for maltase. The IC50 value of MB was 0.36 microg/mL for sucrase, 1.1 microg/mL for isomaltase, and 6.2 microg/mL for maltase. The IC50 value of 1-deoxynojirimycin as the principle component in ME was 0.015 microg/mL for sucrase and 0.21 microg/mL for maltase, and this value was comparable to the IC50 of voglibose. The inhibitory activity of ME in a-amylase was weak. These results suggest that ME strongly suppresses postprandial hyperglycemia after carbohydrate loading by inhibiting the activity of disaccharidases in the small intestine of rats.
authors.affiliation: Department of Food and Drug, Kanagawa Prefectural Public Health Laboratories, 1-1-1 Nakao, Asahi-ku, Yokohama 241-0815, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Miyahara
authors.forename: Maki
authors.initials: M
authors.lastname: Miyazawa
authors.forename: Shuji
authors.initials: S
authors.lastname: Satoh
authors.forename: Anri
authors.initials: A
authors.lastname: Sakai
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Mizusaki
mesh_terms: D017485:1-Deoxynojirimycin / Q000494:pharmacology; D000818:Animals; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D019422:Dietary Sucrose / Q000008:administration & dosage; D004186:Disaccharidases / Q000037:antagonists & inhibitors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005502:Food; D065089:Glycoside Hydrolase Inhibitors; D006943:Hyperglycemia / Q000517:prevention & control*; D007421:Intestine, Small / Q000201:enzymology; D008320:Maltose / Q000008:administration & dosage; D031625:Morus / Q000737:chemistry*; D009834:Oligo-1,6-Glucosidase / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000008:administration & dosage*; D018515:Plant Leaves / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013213:Starch / Q000008:administration & dosage; D013393:Sucrase / Q000037:antagonists & inhibitors
chemical_list: D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D004791:Enzyme Inhibitors; D065089:Glycoside Hydrolase Inhibitors; D010936:Plant Extracts; D017485:1-Deoxynojirimycin; D008320:Maltose; D013213:Starch; D004186:Disaccharidases; D009834:Oligo-1,6-Glucosidase; D013393:Sucrase