title: In-vitro alpha amylase inhibitory activity of the leaf extracts of Adenanthera pavonina.
abstract: BACKGROUND
  Diabetes has caused a major burden to the health sector in the developing countries and has shown an increasing trend among the urban population. It is estimated that most patients are with type II diabetes which could be easily treated with dietary changes, exercise, and medication. Sri Lanka carries a long history ayurvedic medicine where it uses the plant for treating many diseases. Therefore it is important to screen medicinal plants scientifically so they could be used safely and effectively in the traditional medical system and also be used for further investigations. Adenanthera pavonina is a plant used in the Ayurvedic medical system in Sri Lanka for treating many diseases including diabetics. We evaluated the anti-diabetic properties and the antioxidant properties of Adenanthera pavonina leaves.
  
  
  METHODS
  The methanol extract of the leaves was sequentially extracted with petroleum ether and thereafter was partitioned between EtOAc, and water. The α-amylase inhibition assay was performed using the 3,5- dinitrosalicylic acid method. The antioxidant activities were measured using the DPPH free radical scavenging activity and the total phenolic content using Folin-Ciocalteu's reagent. The cytotoxicity of the extract was evaluated using the Brine shrimp bioassay.
  
  
  RESULTS
  The IC50values of α amylase inhibitory activity of MeOH, EtOAc, petroleum ether, and water were 16.16 ± 2.23, 59.93 ± 0.25, 145.49 ± 4.86 and 214.85 ± 9.72 μg/ml respectively and was similar to that of Acarbose (18.63 ± 1.21 (μg/ml). Antioxidant activities were also determined and the EtOAc fraction showed the highest total phenolic content (34. 62 ± 1.14 mg/g extract) and the highest DPPH scavenging activity with an IC50of 249.92 ± 3.35 μg/ml.
  
  
  CONCLUSIONS
  The leaf extracts of Adenanthera pavonina exhibit remarkable α-amylase inhibitory activity in the crude methanolic extract. Hence leaves of Adenanthera pavonina has a potential to be used as a regular green vegetable and also be investigated further in isolating pure compounds with anti-diabetic activity.
authors.affiliation: Department of Physical Sciences and Technology, Faculty of Applied Sciences, Sabaragamuwa University of Sri Lanka, Belihuloya, Sri Lanka. meritanirmali@gmail.com.
authors.forename: M Nirmali
authors.initials: MN
authors.lastname: Wickramaratne
authors.affiliation: Department of Pharmacy Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya, Sri Lanka.
authors.forename: J C
authors.initials: JC
authors.lastname: Punchihewa
authors.affiliation: Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya, Sri Lanka.
authors.forename: D B M
authors.initials: DB
authors.lastname: Wickramaratne
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000737:chemistry*; D007887:Fabaceae / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008515:Medicine, Ayurvedic; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry; D000516:alpha-Amylases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D000516:alpha-Amylases