## 3 Results and Discussion
### In Vitro Antioxidant Activity of Green Tea Extracts
#### 3.1.1 DPPH Radical scavenging Activity (RSADPPH)  
Table 1 presents the RSADPPH results of green tea samples, expressed as EC\({}_{50}\) (ug/mL), showing higher activity in 2020 than in 2019, with the exception of the slightly lower value (higher EC50) in August 2020, which was most likely due to lower sunlight intensity during this month. Furthermore, the results also show better values (lower EC\({}_{50}\) indicates higher antioxidant activity) in the summer season (July and August) of both 2020 and 2019, decreasing in the following order: 3.94 ug/mL (July) > 4.38 ug/mL (August) > 4.80 ug/mL (June) > 5.09 ug/mL (April) > 5.76 ug/mL (May) for 2020, and 4.10 ug/mL (July) > 4.13 ug/mL (August) > 5.37 ug/mL (June) > 6.37 ug/mL (April) > 6.67 ug/mL (May) for 2019. The better results in the summer months in comparison to the spring months can be explained by the greater sunlight intensity during this season. Moreover, all samples presented better antioxidant capacity than that of BHT (EC\({}_{50}\) = 25.84 ug/mL). Significantly lower RSADPPH values (higher EC\({}_{50}\)) were reported by some authors [29,30] for green tea samples (EC\({}_{50}\) = 30-40 ug/mL) compared to our results.  
According to [PERSON] et al. [31], tea extracts enriched with phenolic compounds showed much higher DPPH scavenging ability and, therefore, Azorean tea may also depend on the TP and TF contents in the extracts. However, it is well known that the antioxidant activity of tea samples not only depends on the levels of antioxidants (i.e., high TP) but also on their chemical structure and synergistic, or antagonistic, effect among tea compounds.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Months of Sample Collection and Control**} & **RSADPPH (EC\({}_{50}\)2, ug/mL)** & **FRAP (EC\({}_{50}\)3, ug/mL)** \\ \cline{2-4}  & **2019** & **2020** & **2019** & **2020** \\ \hline April & 6.37 \(\pm\) 0.06 \({}^{\rm c}\) & 5.09 \(\pm\) 0.07 \({}^{\rm c}\) & 7.76 \(\pm\) 0.15 \({}^{\rm d}\) & 6.61 \(\pm\) 0.06 \({}^{\rm b}\) \\ May & 6.67 \(\pm\) 0.21 \({}^{\rm c}\) & 5.76 \(\pm\) 0.04 \({}^{\rm d}\) & 7.02 \(\pm\) 0.04 \({}^{\rm b}\) & 7.05 \(\pm\) 0.04 \({}^{\rm b}\) \\ June & 5.37 \(\pm\) 0.03 \({}^{\rm b}\) & 4.80 \(\pm\) 0.11 \({}^{\rm b}\) & 7.48 \(\pm\) 0.08 \({}^{\rm d}\) & 6.58 \(\pm\) 0.12 \({}^{\rm b}\) \\ July & 4.10 \(\pm\) 0.10 \({}^{\rm a}\) & 3.94 \(\pm\) 0.04 \({}^{\rm a}\) & 6.64 \(\pm\) 0.13 \({}^{\rm a}\) & 5.85 \(\pm\) 0.18 \({}^{\rm a}\) \\ August & 4.13 \(\pm\) 0.06 \({}^{\rm a}\) & 4.38 \(\pm\) 0.05 \({}^{\rm ab}\) & 6.40 \(\pm\) 0.11 \({}^{\rm a}\) & 5.46 \(\pm\) 0.11 \({}^{\rm a}\) \\ BHT \({}^{\rm d}\) & 25.84 \(\pm\) 0.58 & & 8.51 \(\pm\) 0.31 \\ \hline \hline \end{tabular} \({}^{\dagger}\) Values are mean \(\pm\) SD (\(n=3\)). Different superscript letters are significantly different (\(p<0.05\)) within the same column. \({}^{\rm 2}\) Half-maximal effective concentration. \({}^{\rm 3}\) Effective concentration at which the absorbance is 0.5. \({}^{\rm d}\) Reference sample at the same concentration of the extracts. BHT—butylated hydroxytoluene.  
\end{table}
Table 1: DPPH radical scavenging activity (RSADPPH) and ferric reducing antioxidant power (FRAP) in dry extracts of Azorean _Camellia sinensis_ (L.) [PERSON] green tea samples from Gorreana Tea Plantation that were obtained during the collection seasons of two different years \({}^{\rm 1}\).