ABTS Assay-Determination of the TEAC Value

The ABTS + radical cations were performed by the reaction of an aqueous solution of KjSjOg (3.3 mg) in water (5 ml) with ABTS (17.2 mg). The resulting bluish green radi-cd cation solution was stored overnight in the dark below O C. Before experiment, the solution (1 ml) was diluted into a final volmne (60 ml) with water [11]. 

Arbutin solution was prepared as specified under the paragraph Preparation of stock and working solutions . The investigated samples comprised 2 ml of the diluted ABTS + solution with addition of 50 pi of working arbutin solution (1 mM). 

A modified ABTS assay was run applying a UVAHS S2000 spectrophotometer (Sentronic, Germany). The UV/VIS spectra were taken up to 120 min The relative differences (AA) in the light absorbance at 731 inn in the 10th and 120th min compared to the reference experiment using Trolox were used to calculate the values of Trolox Equivalent of Antioxidant Capacity (TEAC). 

The ABTS + radical cation solution (250 pi) prepared from 7 mM ABTS and 2.45 mM KjSjOg, 1 1 vA ratio of water solutions was added to 2.5 pi of the arbutin solution and the absorbance of the sample mixture was measined at 734 nm after 6 min. The radical scavenging capacity of arbutin was investigated at the drag concentration range 2-1000 pM. 

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