Consumption of Amaranth Induces the Accumulation of the Antioxidant Protein Paraoxonase/Arylesterase 1 and Modulates Dipeptidyl Peptidase IV Activity in Plasma of Streptozotocin-Induced Hyperglycemic Rats

Abstract

"Scope: Amaranth grain is a source of several bioactive compounds such as cancer-preventive and ACE inhibitory peptides. In vitro analysis of amaranth proteins has also demonstrated the presence of bioactive peptides, which exert inhibitory activity upon dipeptidyl peptidase IV (DPPIV), a new target for type 2 diabetes, but this potential activity has not been tested in vivo. The aim of this work was to evaluate whether chronic amaranth consumption has a beneficial effect in streptozotocin-induced diabetic rats, particularly in DPPIV activity and changes in plasma proteome profile. Methods and results: Diabetic rats were fed with 20% popped amaranth grain diet for 12 weeks. Changes in lipid profile, DPPIV activity in plasma and kidney, as well changes in plasma proteome were evaluated. Total cholesterol and DPPIV activity in plasma were increased in diabetic rats but this was ameliorated by amaranth consumption. Diabetic rats fed with amaranth showed the highest levels of HDL and this correlated with an accumulation of apolipoprotein (apo) A-II. Furthermore, amaranth diet stimulated the up-accumulation of the antioxidant protein paraoxonase 1(PON1). Conclusion This study provides molecular evidence about the role of amaranth as a potential functional food with DPPIV inhibitory activity and with a positive effect in plasma lipoproteins."