In vitro alpha-glucosidase and alpha-amylase enzyme inhibitory effects of Andrographis paniculata extract and andrographolide.
There has been an enormous interest in the development of alternative medicines for type 2 diabetes, specifically screening for phytochemicals with the ability to delay or prevent glucose absorption. The goal of the present study was to provide in vitro evidence for potential inhibition of alpha-glucosidase and alpha-amylase enzymes, followed by a confirmatory in vivo study on rats to generate a stronger biochemical rationale for further studies on the ethanolic extract of Andrographis paniculata and andrographolide. The extract showed appreciable alpha-glucosidase inhibitory effect in a concentration-dependent manner (IC(50)=17.2+/-0.15 mg/ml) and a weak alpha-amylase inhibitory activity (IC(50)=50.9+/-0.17 mg/ml). Andrographolide demonstrated a similar (IC(50)=11.0+/-0.28 mg/ml) alpha-glucosidase and alpha-amylase inhibitory activity (IC(50)=11.3+/-0.29 mg/ml). The positive in vitro enzyme inhibition tests paved way for confirmatory in vivo studies. The in vivo studies demonstrated that A. paniculata extract significantly (P<0.05) reduced peak blood glucose and area under curve in diabetic rats when challenged with oral administration of starch and sucrose. Further, andrographolide also caused a significant (P<0.05) reduction in peak blood glucose and area under the curve in diabetic rats. Hence alpha-glucosidase inhibition may possibly be one of the mechanisms for the A. paniculata extract to exert antidiabetic activity and indicates that AP extract can be considered as a potential candidate for the management of type 2 diabetes mellitus.
Department of Pharmacology, School of Pharmacy, Universiti Sains Malaysia, Penang, Malaysia. rmohans02@yahoo.co.in
Rammohan
R
Subramanian
M Zaini
MZ
Asmawi
Amirin
A
Sadikun
D035685:Andrographis / Q000737:chemistry*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D004224:Diterpenes / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005951:Glucose Tolerance Test; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents / Q000494:pharmacology; D066298:In Vitro Techniques; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013213:Starch / Q000008:administration & dosage; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
D001786:Blood Glucose; D004224:Diterpenes; D004791:Enzyme Inhibitors; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D010936:Plant Extracts; C030419:andrographolide; D013213:Starch; D000516:alpha-Amylases