Statistical analyses of results were performed using Minitab statistical
software package version 16 . One-way
analysis of variance (ANOVA) and Tukey’s multiple comparisons
were carried out to test any significant differences among means,
with a confidence level of 95%. One-way analysis of variance
(ANOVA) and Dunnett’s comparisons were carried out to test any
significant differences between each test mean and a control mean,
where the confidence level was set at 95%. Significant levels were
defined using p 6 0.05. For the correlations, the Minitab statistical
software package version 16 (Coventry, UK) was used to determine
the Pearson’s correlation coefficient (r) between the content of
total phenols, flavonoids and condensed tannin, to the activity
(%) of each antioxidant attribute. EC50 determinations were calculated
using GraphPad PRISM, version 6.03 for Windows (GraphPad
Software, California, USA). The data was fitted by nonlinear regression
to the variable slope dose–response curves, with a confidence
interval of 95%. Y was the percent activity and X was the
corresponding Log [extract concentration]. The interpolated EC50
parameter is the absolute EC50, and it is defined as the effective
concentration giving an inhibition of 50%.