Anti-oxidant and anti-diabetic activities of Lespedeza cuneata water extract

Abstract

Oxidative damage induced by free radicals are the attendant causes of many chronic diseases. The purpose of this study was to investigate whether Lespedeza cuneata water extract (LCW) has anti-oxidant and anti-diabetic activities in vitro. Anti-oxidant activity was measured by superoxide anion (O2-), hydroxyl (·OH) radical, nitric oxide (NO) and peroxynitrite (ONOO-) scavenging assays. Further, radical-mediated protein oxidation was measured by an allophycocyanin assay. Alpha-glucosidase, dipeptidyl peptidase (DPP)-IV and anti-glycation assays were conducted to measure its anti-diabetic activities. LCW significantly inhibited O2-, ·OH and ONOO- formation. LCW strongly protected radical-induced allophycocyanin degradation during 60 min from the initiation of the reaction. LCW significantly inhibited α-glucosidase, DPP-IV and advanced glycation end product formation. Our results suggest that LCW had both anti-oxidant and anti-diabetic activities, and could be used for the prevention and treatment of oxidative stress and diabetes.     Key words: Free radicals, dipeptidyl peptidase (DPP)-IV, α-glucosidase, Lespedeza cuneata, diabetes.