ABSTRACT
BACKGROUND: Sulphonylureas are the oldest and commonly used to treat diabetic patients, but its efficacy declines by time. It was reported that quinazoline nucleus exhibits a potent hypoglycemic effect in diabetic animal models. OBJECTIVE: The current study aimed to synthesize new quinazoline-sulfonylurea conjugates and evaluate their hypoglycemic effects in alloxan-induced diabetic rats. METHODS: The conjugates were synthesized by bioisosteric replacement of 5-chloro-2-methoxybenzamide moiety in glibenclamide or 1,3-dioxo-3,4-dihydroisoquinoline moiety in gliquidone with 6,7-dimethoxy-4-oxoquinazoline moiety (compounds 4a-4d, 9b-9c and 10b-10d). Diabetes was induced in rats by a single i.p. administration of alloxan, followed by treatment with the synthesized conjugates (5mg/kg Body weight). RESULTS: All conjugates showed hypoglycemic effects with different efficacy indicated by the reduction in blood glucose and elevation of insulin levels. Moreover, these conjugates up-regulated the expression of pancreatic glucose transporter 2, muscle glucose transporter 4, and insulin receptor substrate-1 genes, compared to the diabetic group. A normal pancreatic tissue pattern was noticed in diabetic rats treated with compounds 9b, 9c, and 10c. CONCLUSION: Conjugation of sulfonylurea with quinazoline (especially 9b, 9c, 10c) possessed a significant hypoglycemic effect through improving blood insulin level and insulin action and consequently increased the glucose uptake by the skeletal muscles.