Objective: The pericarp of fruits of Cucumis callous (Rottl.) Cogn. (Cucurbitaceae) is traditionally used for curing diabetes, epilepsy, and diarrhea. It has an active compound include Cucurbitacin-B (CuB), which acts as a potent inducer of CYP450 of rat enterocytes. This study was conducted with the aim of elaborating and reconciling our previous finding on the glucose-lowering effect of Cucumis callosus (Rottl.) Cogn. fruits.Methods: In vivo hypoglycemic potential for methanolic pericarp extracts from C callosus (MPCC, 350 mg/kg b.w. p. o), methanolic seed extract of C callosus (MSCC, 250 mg/kg b.w. p. o) and CuB (80 µg/kg b.w. p. o) were studied in streptozotocin (STZ, 55 mg/kg b.w. i. p) induced diabetic rats. Metformin (25 mg/kg b.w. p. o) served as reference drug. Ex vivo model of intestinal tissue preparation of Swiss albino rats named Single Pass Intestinal Perfusion (SPIP) technique was performed for ex vivo hypoglycemic study. The glucose levels in the serosal fluid were determined by commercially available glucose oxidase kit and compared with the standard drug metformin (0.1 mg/kg).Results: In vivo results showed that administration of MPCC (350 mg/kg b.w. p. o) and Cucurbitacin-B (80 µg/kg b.w. p. o) produced the hypoglycemic effect. The MPCC (1.4 mg/kg) and CuB (0.4 µg/kg) produced hypoglycemic effect in ex vivo technique. These effects are due to induction of 0.53 mµmoles of CYP450 proteins with maximum absorption at 454 mµ in rat enterocytes.Conclusion: The present investigation gave evidence that bitter pericarp of C callosus fruit has a hypoglycemic effect due to the presence of Cucurbitacin B as phytoconstituent but seeds did not have such effects
