ABSTRACT
A novel 13-membered ring thiocyclitol, isolated from an aqueous extract of Kothala-himbutu (Salacia reticulata), inhibited alpha-glucosidase in vitro. The inhibitory activity was investigated by maltose- and sucrose-loading on Wistar rats. This study found significant lowering of postprandial glucose levels, and the potency of 13-membered ring thiocyclitol was confirmed in vivo.
Subject(s)
Cyclitols/pharmacology , Enzyme Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors , Salacia/chemistry , Animals , Blood Glucose/drug effects , Cyclitols/isolation & purification , Enzyme Inhibitors/isolation & purification , Hypoglycemic Agents/isolation & purification , Hypoglycemic Agents/pharmacology , Maltose/blood , Postprandial Period , Rats , Rats, Wistar , Sucrose/bloodABSTRACT
A polyhydroxylated cyclic 13-membered sulfoxide (1) was isolated from an aqueous extract of Kothala-himbutu ( Salacia reticulata WIGHT). The structure of compound 1 was elucidated by 1D and 2D NMR and APCI-MS methods. The alpha-glucosidase inhibitory activity of compound 1 (IC 50: maltase, 0.227 microM; sucrase, 0.186 microM; isomaltase, 0.099 microM) was much greater than the inhibitory activity of salacinol and kotalanol, which were previously isolated from Kothala-himbutu.
Subject(s)
Glycoside Hydrolase Inhibitors , Heterocyclic Compounds, 1-Ring/isolation & purification , Heterocyclic Compounds, 1-Ring/pharmacology , Plants, Medicinal/chemistry , Salacia/chemistry , Sulfur Compounds/isolation & purification , Sulfur Compounds/pharmacology , Animals , Heterocyclic Compounds, 1-Ring/chemistry , Intestine, Small/enzymology , Molecular Structure , Monosaccharides/chemistry , Monosaccharides/isolation & purification , Pancreas/enzymology , Rats , Sri Lanka , Sucrase/drug effects , Sugar Alcohols/chemistry , Sugar Alcohols/isolation & purification , Sulfates/chemistry , Sulfates/isolation & purification , Sulfur Compounds/chemistry , Swine , alpha-Amylases/antagonists & inhibitors , alpha-Glucosidases/drug effectsABSTRACT
B. Ludvik et al., have recently shown the effect of Caiapo (Ipomoea batatas L.) on reducing fasting blood glucose and insulin resistance in type-2 diabetic patients. It, however, was required 2-4 weeks after the single administration of Caiapo. The present study aimed to determine if the combination therapy of Caiapo with a mulberry leaf powder, which inhibits alpha-glucosidase, or with a loquat leaf extract, which shows an insulin-like effect, could make it possible to enhance the antidiabetic activities of Caiapo, and to shorten the time necessary for the inhibition of increasing blood glucose levels. A mixture of the pulverized tuber of Caiapo (357 mg/kg) and the mulberry leaf powder (143 mg/kg), or a mixture of the pulverized skin of Caiapo (194 mg/kg) and the powdered loquat leaf extract (6 mg/kg) was orally administered to 6 weeks-old male KK-Ay mice for 28 days and the glucose loading test was conducted every 7 days. In the glucose loading test after one week feeding, a reduction in blood glucose concentration after 60 minutes of the administration of glucose was observed in both mixture groups against the control group (p < 0.05) in the case of Caiapo only, similar delayed effects were seen in 2-3 weeks after feeding.
