Dipeptidyl peptidase-4 inhibitor

Abstract

The present invention aims to provide a DPP-4 inhibitor that is obtained by using a food as a raw material and that is suitable for oral ingestion from the viewpoints of flavor and absorbability, and a composition for the prevention and/or amelioration of diabetes which contains the DPP-4 inhibitor. The present invention provides a DPP-4 inhibitor obtained by treating an azuki bean or a kidney bean with a microorganism or a proteolytic enzyme produced by the microorganism. In particular, a preferable DPP-4 inhibitor can be obtained by hydrolyzing an azuki bean with a koji mold or a proteolytic enzyme derived from the koji mold to fragment a protein in the azuki bean.

1 .- 7 . (canceled) 
     
     
         8 . A composition for use in the prevention and/or amelioration of diabetes, comprising the DPP-4 inhibitor obtained by the method according to  claim 9 . 
     
     
         9 . A method of producing a DPP-4 inhibitor, comprising treating an azuki bean, a kidney bean or a treated bean thereof, suspended or dissolved in water with a proteolytic enzyme produced by the a microorganism. 
     
     
         10 . (canceled) 
     
     
         11 . The method of producing a DPP-4 inhibitor according to  claim 9 ,
 wherein the proteolytic enzyme is one or more enzymes derived from one or more types of microorganisms selected from the group consisting of koji molds, lactic acid bacteria., and natto bacteria.   
     
     
         12 . (canceled) 
     
     
         13 . The method of producing a DPP-4 inhibitor according to  claim 11 ,
 wherein the koji mold is  Aspergillus oryzae  or  Aspergillus sojae.      
     
     
         14 . The method of producing a DPP-4 inhibitor according to  claim 9 ,
 wherein the proteolytic enzyme comprises a peptidase.   
     
     
         15 . The method of producing a DPP-4 inhibitor according to  claim 9 ,
 wherein the proteolytic enzyme has X-prolyl dipeptidyl aminopeptidase activity.   
     
     
         16 . A method for the prevention and/or amelioration of diabetes, comprising administrating to a subject the DPP-4 inhibitor obtained by the method according to  claim 9 .