## 3 Results and Discussion
### Characterization of Nanoparticles
This analysis revealed low values of AA for both NPs, where the extract-loaded PLGA NPs in PBS at pH 5.5 is higher than at pH 7.4 (\(14.9\pm 1.3\%\) versus \(14.3\pm 5.7\%\)), thus corroborating the release assays, where the extract is delivered easier at pH 5.5. The extract-loaded PCL NPs presents similar values at pH 7.4 and at pH 5.5 (\(6.4\pm 1.3\%\)_versus_\(5.1\pm 1.2\%\)), whereas for the free extract an AA lower than 30% was observed under same conditions, while the degraded NPs did not reveal any AA by DPPH. The other two methods (ORAC and HOSC) were used to get further information about the decrease of AA. The results presented in Figure 11a were obtained by Trolox equivalent antioxidant  
Figure 10: **(a)** AA of quercetin and ascorbic acid (positive controls), free extract, extract-loaded PLGA NPs, extract-loaded PCL NPs, (%, mean \(\pm\) S.D. ; n = 3, *** \(p<0.001\), when compared the quercetin with the other samples, *** \(p<0.001\), when compared the ascorbic acid with the other samples, *** \(p<0.001\), when compared the free extract with the other samples and \(\Delta\Delta\Delta\)\(p<0.001\), when compared the rutin with the other samples), **(b)** Difference of AA in release medium when compared with respective extract-loaded NPs (%, mean \(\pm\) S.D. ; \(n=3\)). capacity (TEAC, umol/g of sample) which means that for free extract is umol/g of extract, rutin is umol/g of rutin and for extract-loaded NPs is umol/g of NPs. The oxygen radical absorbance capacity (ORAC) and the hydroxyl radical scavenging capacity (HOSC) were used to estimate the AA of extract and extract-loaded NPs. The results suggest that the percentage of rutin in the extract is around 43.82% and 51.22% for ORAC and HOSC, respectively. Values were in line with the previous findings, where rutin was identified as a major compound. But other polyphenols in this extract might be responsible for the remaining TEAC of the extract. The results were the expected due to the extract-loaded NPs, being faster for PLGA NPs than for PCL NPs [45; 46]. However, these values are still lower when compared to the free extract, suggesting that the extract is really encapsulated into the NPs, as already mentioned. Concerning the extract-loaded PLGA NPs degraded, there was a decrease of the TEAC when compared to the PLGA NPs, 13.08 \(\pm\) 4.21% (\(n\) = 9) and 17.93 \(\pm\) 9.19% (\(n\) = 9) for ORAC and HOSC, respectively. Furthermore, the extract-loaded PCL NPs degraded showed an increase of the TEAC when compared to the extract-loaded PCL NPs, 40.07 \(\pm\) 4.32% (\(n\) = 4) and 152.36 \(\pm\) 15.20% (\(n\) = 6) for ORAC and HOSC, respectively. These differences correspond to the fold-factors presented in Figure 11b. To conclude, the AA assessed by three different methods showed unexpected and somehow disappointing results. The ORAC method has been widely accepted as a standard tool to measure the AA in the nutraceuticalital, pharmaceutical, and food industries [19]. Same experimental details may also contribute for this outcome, which does not allow an extensive release of the extract. The extract-loaded NPs displayed different behaviors according to the polymer. Apparently, the compounds responsible for AA were not released from both types of NPs or may have suffered some degradation. Further studies should be conducted in order to elucidate this finding. Nevertheless, the TEAC value was very high after encapsulation, thus corroborating literature and suggesting a potential synergetic effect of the compounds present in the extracts. The TPC was also assessed and the free extract presented a TPC value of 1605 \(\pm\) 66 mg gallic acid equivalent (GAE)/L, whereas the extract-loaded PLGA and PCL NPs did not show any polyphenol content using these experimental conditions. This assay is in accordance with the AA determined by the DPPH method.