title: Effect of Opuntia streptacantha Lem. on alpha-glucosidase activity.
abstract: BACKGROUND
  In Mexico, Opuntia streptacantha is used as part of a traditional medicine in the treatment of diabetes mellitus. Several studies have reported an anti-hyperglycemic effect from the plant, but none have focused on finding a mechanism of action to explain these results. This paper focuses on one of the most recurrent hypotheses for the effect of O. streptacantha: the mechanism of action is the hydrolysis of disaccharides, either by enzymatically inhibiting the alpha glucosidase inhibitors (AGIs) or mechanically acting as a barrier.
  
  
  METHODS
  To test our hypothesis, three different experiments were performed. A maltose tolerance test was carried out using the total extract (TE) and the juice of the plant. Six different extracts were tested in a free-enzyme assay, four of which were aqueous extracts varying according to the procedure of removing the insoluble particles in an attempt to reduce the loss of the water-soluble compounds. The main component of the total extract, a derivative of (4-hydroxy)-phenyl acetic acid, was also tested. For both the maltose tolerance test and the free-enzyme assay, acarbose was used as a control drug. Finally, an everted small intestine assay was also performed.
  
  
  CONCLUSIONS
  The maltose tolerance test confirmed that an anti-hyperglycemic effect occurs at doses of 100 mg/kg TE and 4 mL/kg juice. No inhibition on AGIs was observed in the free-enzyme assay, and neither a mechanic nor enzymatic effect on disaccharide hydrolysis was observed in the everted intestine assay.
  
  
  CONCLUSIONS
  The anti-hyperglycemic effect of O. streptacantha was confirmed, and the results presented here contribute to the understanding that this effect is not due to the action on alpha-glucosidases or related to the intestinal hydrolysis of disaccharides.
authors.affiliation: Pharmaceutical Institute of the University of Bonn, Bonn, Germany.
authors.forename: Jaime
authors.initials: J
authors.lastname: Becerra-Jiménez
authors.forename: Adolfo
authors.initials: A
authors.lastname: Andrade-Cetto
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology; D006868:Hydrolysis; D007004:Hypoglycemic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D007421:Intestine, Small / Q000187:drug effects* / Q000201:enzymology; D008320:Maltose / Q000008:administration & dosage / Q000378:metabolism; D029747:Opuntia / Q000737:chemistry; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D051381:Rats; D017208:Rats, Wistar; D000520:alpha-Glucosidases / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D008320:Maltose; D000520:alpha-Glucosidases