DPPH Assay

The method provides information on the ability to scavenge the radical DPPH (1,1-Diphenyl-2-picrylhydrazyl), based on the mechanisms of mixed transfer of the hydrogen atom (HAT) and single electron transfer. The analyzed sample (0.15 mL) was mixed with 2.85 mL freshly made 0.1 mM DPPH solution (Sigma-Aldrich Chemie GmbH, Darmstadt, Germany) in methanol (Merck KGaA, Darmstadt, Germany). The sample was incubated for 15 min at 37 ◦C in the dark. The reduction in the absorbance at 517 nm was measured by spectrophotometer a VIS spectrophotometer Camspec M107 (Spectronic-Camspec Ltd., Leeds, the United Kingdom) in comparison to control sample containing methanol and the % inhibition was calculated [18]. A standard curve with 6-hydroxy-2,5,7,8- tetramethylchroman-2-carboxylic acid (Trolox) (Sigma-Aldrich Chemie GmbH, Darmstadt, Germany) at a concentration of 0.005–1.0 mM was generated. The results of the assay are presented as millimoles of Trolox equivalents (mM TE)/g dry weight sample.
