title: Potent α-glucosidase and α-amylase inhibitory activities of standardized 50% ethanolic extracts and sinensetin from Orthosiphon stamineus Benth as anti-diabetic mechanism.
abstract: BACKGROUND
  In the present study, we tested a 50% ethanolic extract of Orthosiphon stamineus plants and its isolated bioactive compound with respect to their α-glucosidase and α-amylase inhibitory activities.
  
  
  METHODS
  Bioactive flavonoid sinensetin was isolated from 50% ethanolic extract of Orthosiphon stamineus. The structure of this pure compound was determined on the NMR data and the α-glucosidase and α-amylase inhibitory activities of isolated sinensetin and 50% ethanolic extract of Orthosiphon stamineus were evaluated.
  
  
  RESULTS
  In vitro studies of a 50% ethanolic extract of O. stamineus and the isolated sinensetin compound showed inhibitory activity on α-glucosidase (IC50: 4.63 and 0.66 mg/ml, respectively) and α-amylase (IC50: 36.70 mg/ml and 1.13 mg/ml, respectively). Inhibition of these enzymes provides a strong biochemical basis for the management of type 2 diabetes via the control of glucose absorption.
  
  
  CONCLUSIONS
  Alpha-glucosidase and α-amylase inhibition could the mechanisms through which the 50% ethanolic extract of O. stamineus and sinensetin exert their antidiabetic activity, indicating that it could have potential use in the management of non-insulin-dependent diabetes.
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang 11800, Malaysia. aliali692002@yahoo.com
authors.forename: Elsnoussi Ali Hussin
authors.initials: EA
authors.lastname: Mohamed
authors.forename: Mohammad Jamshed Ahmad
authors.initials: MJ
authors.lastname: Siddiqui
authors.forename: Lee Fung
authors.initials: LF
authors.lastname: Ang
authors.forename: Amirin
authors.initials: A
authors.lastname: Sadikun
authors.forename: Sue Hay
authors.initials: SH
authors.lastname: Chan
authors.forename: Soo Choon
authors.initials: SC
authors.lastname: Tan
authors.forename: Mohd Zaini
authors.initials: MZ
authors.lastname: Asmawi
authors.forename: Mun Fei
authors.initials: MF
authors.lastname: Yam
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D065089:Glycoside Hydrolase Inhibitors; D006801:Humans; D007004:Hypoglycemic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D031342:Orthosiphon / Q000737:chemistry*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D000516:alpha-Amylases