Jerusalem artichoke and chungkookjang additively improve insulin secretion and sensitivity in diabetic rats

Abstract

Jerusalem artichoke (Helianthus tuberosus Linne, HTL) and chungkookjang (CKJ; fermented soybeans) both modulate energy and glucose metabolism. However, the mechanism and their additive effects are unknown. We investigated whether the consumption of HTL and CKJ altered insulin sensitivity, insulin secretion capacity and β-cell survival in type 2 diabetic animals. Rats were divided into partially pancreatectomized (Px) diabetic rats, and sham operated non-diabetic control rats and all fed high fat diets. Diabetic rats were sub-divided into an untreated diabetic control group and those fed 5% HTL, 5% CKJ or 5% HTL+5% CKJ for 8 weeks. HTL+CKJ treatment reduced visceral fat without modulating energy intake compared to the diabetic-control. Glucose tolerance was improved in an ascending order of diabetic-control, CKJ, HTL, HTL+CKJ, and normal-control, but by different mechanisms. CKJ and CKJ+HTL, but not HTL, increased first and second phase insulin secretion in comparison to the diabetic-control at hyperglycemic clamp. However, glucose infusion rates (mg/kg bw/min) were increased by and CKJ+HTL (13.5), but not HTL (9.4) or CKJ (9.5) alone, and HTL and CKJ+ HTL decreased hepatic glucose compared to diabetic-control during the hyperinsulinemic euglycemic study and were associated with decreased triglyceride accumulation and increased glycogen storage. The improved hepatic insulin sensitivity by HTL and CKJ+HTL was explained by potentiated insulin signaling (tyrosine phosphorylation of insulin receptor substrate 2→phosphorylation of Akt) and phosphorylation of AMPK→phosphorykation of acetyl Co carboxlase in comparison to diabetic-control and decreased PEPCK expression. Absolute β-cell mass was increased by CKJ (23.4mg) and CKJ+HTL (26.3 mg) by increasing proliferation compared to the diabetic-control (21.26 mg). Although HTL lowered β-cell apoptosis, it did not increase β-cell mass (20.8 mg). In conclusions, HTL and CKJ enhanced glucose tolerance in different manners, and exhibited partially additive and complementary effects by reversing insulin resistance and enhancing β-cell function in diabetic rats.

Fermentation of purple Jerusalem artichoke extract to improve the α-glucosidase inhibitory effectin vitroand ameliorate blood glucose indb/dbmice

“…Also, Jerusalem artichoke decrease fasting serum glucose levels perhaps due to it is rich in fructan and coumarins [ 13 22 ]. Jerusalem artichoke had anti-diabetic effects due to high in fructoligossacharides that may decrease insulin resistance by mechanisms that remain unknown [ 23 ]. Therefore, the degree of polymerization of fructan is considered as a factor that influences hyperglycemia amelioration and α-glucosidase inhibitory activity.…”

Topinambur – new possibilities for use in a supplementation diet

“…Similar to TPB, chungkookjang (CKJ; fermented soybeans) has also been considered to modulate energy and glucose metabolism. Yang et al [41] evaluated an anti-diabetic effects of TPB and CKJ supplementary diet in diabetic rats. Animals were divided into four experimental groups (diabetic-control, CKJ, CKJ+TPB, and TPB).…”

Helianthus tuberosus

“…Administration of the ethanol extract of H. tuberosus tuber exhibited an inhibitory effect (24.5 %) on diabetic rat kidney tissue thiobarbituric acid reactive substance (TBARS) levels but did not restore GSH (reduced glutathione) levels in the kidney, liver and heart tissues of diabetic rats (Aslan et al 2010 ). Studies by Yang et al ( 2012 ) reported that Jerusalem artichoke and chungkookjang (fermented soybeans) enhanced glucose tolerance in different manners and exhibited partially additive and complementary effects by reversing insulin resistance and enhancing β-cell function in diabetic rats. The combined treatment reduced visceral fat without modulating energy intake compared to the diabetic control.…”