title: Phenolic-rich extracts from selected tropical underutilized legumes inhibit α-amylase, α-glucosidase, and angiotensin I converting enzyme in vitro.
abstract: BACKGROUND
  In this study, interaction of free and bound phenolic extracts from selected tropical underutilized legumes (a popular folklore for the management of diabetes and hypertension) with key enzymes linked to type 2 diabetes (α-glucosidase and α-amylase) and hypertension (angiotensin I converting enzyme, ACE) was assessed.
  
  
  METHODS
  The free phenolic extracts of the soybean were obtained by extracting powdered legume seeds with 80% acetone, whereas the residue was subjected to alkaline and acid hydrolysis before extraction with ethyl acetate to obtain the bound extracts. Thereafter, enzyme (α-amylase, α-glucosidase, and ACE) inhibitory studies and antioxidant capacity of the extracts were investigated.
  
  
  RESULTS
  The free and bound phenolic extracts inhibited α-amylase, α-glucosidase, and ACE activities in a dose-dependent manner. However, the free phenolic extracts of all the legumes were stronger inhibitors of α-glucosidase than their corresponding bound phenolic extracts. In addition, the free phenolic extracts (except melon) exhibited stronger ACE inhibition than their corresponding bound phenolic extracts. All the phenolic extracts significantly (p<0.05) inhibited Fe2+-induced oxidative stress in the pancreas (in vitro) and exhibited strong antioxidant activities.
  
  
  CONCLUSIONS
  The inhibition of the α-amylase, α-glucosidase, ACE, and oxidative stress by the phenolic extracts could be a part of the mechanism through which these underutilized legumes manage/prevent type 2 diabetes and hypertension. However, as revealed by this study, bambara groundnut with the best enzyme inhibitory potentials coupled with strong antioxidant properties ranked highest, whereas melon seed ranked least.
authors.affiliation: Department of Biochemistry, Federal University of Technology, Akure, Nigeria. goboh2001@yahoo.com
authors.forename: Adedayo O
authors.initials: AO
authors.lastname: Ademiluyi
authors.forename: Ganiyu
authors.initials: G
authors.lastname: Oboh
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D007887:Fabaceae / Q000737:chemistry; D065089:Glycoside Hydrolase Inhibitors; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D010179:Pancreas / Q000187:drug effects* / Q000201:enzymology; D055292:Pancreatic alpha-Amylases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D051381:Rats; D012639:Seeds; D013552:Swine; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000975:Antioxidants; D004791:Enzyme Inhibitors; D065089:Glycoside Hydrolase Inhibitors; D010636:Phenols; D010936:Plant Extracts; D055292:Pancreatic alpha-Amylases; D000520:alpha-Glucosidases