[24] selleck chemical Seliciclib described by Siddhuraju and Manian [22]. ABTS?+ was produced by reacting 7mM ABTS?+ aqueous solution with 2.4mM potassium persulphate in the dark for 12�C16hr at room temperature. The reagent solution was diluted in ethanol (about 1:89v/v) and equilibrated at 30��C to give an absorbance at 734nm of 0.7 �� 0.02. After the addition of 1mL of diluted ABTS?+ solution to different concentrations of sample or trolox standards (final concentration 0�C15��M) in ethanol, absorbance was measured at 30��C exactly 30min after initial mixing. Triplicate determinations were made at each dilution of the standard, and the percentage inhibition was calculated of the blank absorbance at 734nm, and it was plotted as a function of trolox concentration.

The unit of total antioxidant activity (TAA) is defined as the concentration of trolox having equivalent antioxidant activity expressed as ��Mol/g extract.2.6.3. Radical Scavenging Activity Using DPPH? Method The antioxidant activity of the extracts was determined in terms of hydrogen donating or radical scavenging ability, using the stable radical 2,2-diphenyl-2-picrylhydrazyl(DPPH?), according to the method of Blois [25]. A methanol solution of the sample extracts at various concentrations was added to 5mL of 0.1mM methanolic solution of DPPH? and allowed to stand for 20min at 27��C. The absorbance of the sample was measured at 517nm. Methanol was served as blank, and solution without extract served as control. The mixture of methanol, DPPH, and standard (BHT, BHA, quercetin, and ��-tocopherol) served as positive control.

More significantly, the IC50 of the extracts were also calculated.2.6.4. Ferric Reducing Antioxidant Power (FRAP) Assay The antioxidant capacities of phenolic extracts of samples were estimated according to the procedure described by Pulido et al. [26]. Freshly prepared FRAP reagent (2.5mL of 20mmol/L TPTZ (2,4,6-tripyridyl-s-triazine) solution in 40mmol/l HCl plus 2.5mL of 20mmol/L FeCl3?6H2O and 25mL of 0.3mol/L acetate buffer (pH 3.6)) (900��l) incubated at 37��C was mixed with test sample or methanol (for the reagent blank). The test samples and reagent blank were incubated at 37��C for 30min in a water bath as described by Siddhuraju and Becker [21]. At the end of incubation, the absorbance readings were taken immediately at 593nm. Results were calculated in ascorbic acid equivalents.

2.6.5. Metal Chelating Activity The chelating of ferrous ions by leaf and barkextracts was estimated by the method of Dinis et al. [27]. Briefly, 50��l of 2mM FeCl2 Dacomitinib was added to the extracts. The reaction was initiated by the addition of 0.2mL of 5mM ferrozine solution. The mixture was vigorously shaken and left to stand at room temperature for 10min. The absorbance of the solution was thereafter measured at 562nm. BHT was taken as standard.