title: Evaluation of phytochemical composition and antioxidant capacity of a decoction containing Adenanthera pavonina L. and Thespesia populnea L.
abstract: BACKGROUND
  A decoction prepared with barks of Adenanthera pavonina and Thespesia populnea is a herbal formulation which has been prescribed in Sri Lanka in the treatment of cancer patients for many years. This study was designed to investigate its phytochemical and antioxidant properties.
  
  
  METHODS
  The total phenolics and flavonoids were determined using Folin-Ciocalteau and aluminum chloride colorimetric methods, respectively. Gallic acid content in the decoction was determined using high-performance liquid chromatography. The antioxidant properties were evaluated by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical assay, nitric oxide scavenging assay, deoxyribose method, and the reducing power of the decoction.
  
  
  RESULTS
  The concentration of total phenols, flavonoids, and gallic acid of the decoction were 34.13 ± 3.54 w/w % gallic acid equivalents, 41.37 ± 0.57 w/w % of (-)-Epigallocatechin gallate equivalents, and 0.58 ± 0.24 mg/g, respectively. The EC50 for DPPH, nitric oxide scavenging, and deoxyribose assays were 7.24 ± 0.50, 14.02 ± 0.66, and 53.21 ± 2.82 μg/ml, respectively. Reducing power of the decoction increased with the concentration.
  
  
  CONCLUSIONS
  These investigations suggested that the decoction prepared with A. pavonina and T. populnea can be a potential source of nutraceuticals with antioxidant activity.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Colombo, Sri Lanka.
authors.forename: Indeewari Kalhari
authors.initials: IK
authors.lastname: Silva
authors.forename: Preethi
authors.initials: P
authors.lastname: Soysa