The level of significance that a PC had on a variable can be noted via the loading plots in Supplementary Fig. 3(A and B), which showed the load that each set of data places on the PC. PC1 corresponds to the processing type (in natura, processed or oxidised), and these variables explained 75.8% of the variance among the samples, indicating that this processing type has a great effect on all compounds. The variable growing location, represented as PC2 Nutlin3 (vertical axis) explains 16% of the variance,
in which it was possible to observe that the leaves of sun- and shade-exposed were clustered in different places in this PC axis ( Supplementary Fig. 3A). PC1 was plotted against PC3 (Supplementary Fig. 3B), with corresponds to leaf age and explained 5.8% of the variance. Thus, leaf age had little CDK inhibitor influence on the variation of data. The data of the PCA analysis successfully explain the variance between the samples and one can associate the
PC1, PC2 and PC3 with the variables between the 12 studied samples. The variables that contribute to the variability of the data followed the order: processing type > location growing > leaf age. The DPPH free radical-scavenging activities of Ilex extracts are shown in Table 3. For each treatment, four concentrations (in μg/ml) were tested. The overall scavenging effect of each extract increased with concentration to a similar extent. No significant differences of activity were found between leaf age and growth site, but only with the process method. By comparing the treatments, the free radical-scavenging activity followed the order: processed > in natura > oxidised
leaves. Since this activity is directly related to the concentration of phenolics, the result is in accordance with the phenolic composition of processed leaves. In order to quantify the antioxidant activity, the EC50 was calculated and is shown in Table 3. The lower the EC50 value, the greater was the free radical-scavenging activity. EC values of the DPPH radical-scavenging activity ranged from 158 to 1439 μg/ml. Deladino, Anbinder, Navarro, and Martino (2008) found EC50 to be 0.72 ± 0.09 for liquid extract and 1.05 ± 0.25 for freeze-dried SSR128129E Maté extract. The standard BTH gave rise to a scavenging effect of 92% at a concentration of 200 μg/ml, with the EC50 at 37.8 μg/ml. The antioxidant activity data of the Ilex extracts showed that the absorbance decreased rapidly in the samples without antioxidant, whereas in the presence of an antioxidant the colour was retained for a longer time. BHT, the positive control used in this test, had 92% antioxidant activity at 200 μg/ml. The LPO inhibition by Ilex extracts increased with concentration and as with the DPPH, the processed leaves had a greater antioxidant activity (69%) ( Table 3). Several investigations on Maté compounds were carried out previously using HPLC.