L-arabinose selectively inhibits intestinal sucrase in an uncompetitive manner and suppresses glycemic response after sucrose ingestion in animals.
The objective of this study was to investigate the effects of L-arabinose on intestinal alpha-glucosidase activities in vitro and to evaluate its effects on postprandial glycemic responses in vivo. L-Arabinose inhibited the sucrase activity of intestinal mucosa in an uncompetitive manner (Ki, 2 mmol/L). Neither the optical isomer D-arabinose nor the disaccharide L-arabinobiose inhibited sucrase activity, whereas D-xylose was as potent as L-arabinose in inhibiting this activity. L-Arabinose and D-xylose showed no inhibitory effect on the activities of intestinal maltase, isomaltase, trehalase, lactase, and glucoamylase, or pancreatic amylase. In contrast, a known alpha-glucosidase inhibitor, acarbose, competitively inhibited (Ki, 1.1 mumol/L) sucrase activity and also inhibited intestinal maltase, glucoamylase, and pancreatic amylase. L-Arabinose suppressed the increase of blood glucose after sucrose loading dose-dependently in mice (ED50, 35 mg/kg), but showed no effect after starch loading. The suppressive effect of D-xylose on the increase of blood glucose after sucrose loading was 2.4 times less than that of L-arabinose, probably due to intestinal absorption of the former. Acarbose strongly suppressed glycemic responses in both sucrose loading (ED50, 1.1 mg/kg) and starch loading (ED50, 1.7 mg/kg) in mice. L-Arabinose suppressed the increase of plasma glucose and insulin in rats after sucrose loading, the suppression of the former being uninterruptedly observed in mice for 3 weeks. Thus, the results demonstrated that L-arabinose selectively inhibits intestinal sucrase activity in an uncompetitive manner and suppresses the glycemic response after sucrose ingestion by inhibition of sucrase activity.
Seri
K
K
Pharmacological Section, GODO SHUSEI Co, Chiba, Japan.
Sanai
K
K
Matsuo
N
N
Kawakubo
K
K
Xue
C
C
Inoue
S
S
D020909:Acarbose; D000681:Amylases / Q000037:antagonists & inhibitors; D000818:Animals; D001089:Arabinose / Q000378:metabolism / Q000494:pharmacology*; D001786:Blood Glucose / Q000032:analysis*; D065089:Glycoside Hydrolase Inhibitors; D007328:Insulin / Q000097:blood; D007413:Intestinal Mucosa / Q000201:enzymology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D051381:Rats; D017208:Rats, Wistar; D013393:Sucrase / Q000037:antagonists & inhibitors*; D013395:Sucrose / Q000494:pharmacology*; D013552:Swine; D014312:Trisaccharides / Q000494:pharmacology; D014994:Xylose / Q000494:pharmacology / Q000652:urine
D001786:Blood Glucose; D065089:Glycoside Hydrolase Inhibitors; D007328:Insulin; D014312:Trisaccharides; D013395:Sucrose; D014994:Xylose; D001089:Arabinose; D000681:Amylases; D013393:Sucrase; D020909:Acarbose