## 3 Results and Discussion  
### Microwave-Assisted Extraction  
As extraction methods, Microwave-assisted extraction (MAE), interesting alternative to other methods with a lower time and solvent consumption [26], was chosen to produce functional extracts in a rapid and reproducible manner. As reported by [PERSON] et al. [27], the extraction procedure (solvent, power, time, and liquid:solid ratio) was optimized comparing the obtained extracts in term of polyphenol content. MAE allows also to quickly verify the polyphenolic component in the leaves during ripening to select the richest matrices of polyphenolic component to be enhanced in a healthy ingredient.  
The content of polyphenols in _V. vinifera_ 'Aglianico' and 'Greco di Tufo' leaves is presented in Table 3. For all samples, the highest polyphenol concentrations were obtained with H\({}_{2}\)O as a solvent, followed by MeOH:H\({}_{2}\)O (70:30) and EtOH. MAE carried out at 300 W for 2 min. gave better results than at 180 W for 5 min. Both 'Aglianico' and 'Greco di Tufo' collected in November showed a higher polyphenol concentration with respect to 'Aglianico' and 'Greco di Tufo' collected in October. Microwave-assisted extraction (MAE) is a rapid and efficient extraction technique. Several comparative studies have demonstrated the excellent performances, in terms of recovery and precision, obtainable with MAE compared to other traditional extraction techniques (for example extraction with Soxhlet) and its superiority in terms of reduction of solvent consumption and extraction time [7; 8; 28]. For example, conventional Soxhlet extraction usually requires long extraction times leading also to thermal degradation of phytoconstituents. During MAE process, the internal pressure of the sample is increased by microwaves in a few minutes with the effect of enhanced extraction efficiency and reduce the deterioration of phenolic compounds [9; 27].  
The phenolic content of the extracts was quite dependent on the harvest-time, with both Aglianico and Greco di Tufo collected in November showing the highest concentration of total polyphenols (Table 3).  
The total polyphenols content in 'Aglianico' and 'Greco di Tufo' was quite similar in the two cultivars at the same period of harvesting. Interestingly, [PERSON] et al. [29] report that vine leaves extracts of six different varieties collected in September were the richest in total phenols, flavonoids, flavonoids, and stilbenes, with respect to May and  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**Polyphenols (mg/g)**} \\ \hline
**180 W 5 min** & \multicolumn{3}{c}{**Extraction Solvent**} \\ \hline  & EtOH & MeOH:H\({}_{2}\)O & H\({}_{2}\)O \\ \hline Aglianico October (AGL-1) & 24.92 \(\pm\) 3.11 & 40.69 \(\pm\) 3.76 & 75.39 \(\pm\) 6.93 \\ Aglianico November (AGL-2) & 26.14 \(\pm\) 1.98 & 54.99 \(\pm\) 4.99 & 83.61 \(\pm\) 7.45 \\ Greco di Tufo October (GRC-1) & 17.43 \(\pm\) 2.12 & 45.34 \(\pm\) 3.56 & 79.18 \(\pm\) 6.43 \\ Greco di Tufo November (GRC-2) & 28.80 \(\pm\) 3.71 & 25.76 \(\pm\) 2.41 & 87.79 \(\pm\) 7.51 \\ \hline
**300 W 2 min** & \multicolumn{3}{c}{} \\ \hline  & EtOH & MeOH:H\({}_{2}\)O & H\({}_{2}\)O \\ \hline Aglianico October (AGL-18) & 16.00 \(\pm\) 1.11 & 26.16 \(\pm\) 2.05 & 83.99 \(\pm\) 7.49 \\ Aglianico November (AGL-28) & 23.42 \(\pm\) 1.57 & 43.64 \(\pm\) 3.94 & 100.67 \(\pm\) 9.29 \\ Greco di Tufo October (GRC-18) & 26.07 \(\pm\) 1.99 & 35.47 \(\pm\) 3.12 & 80.96 \(\pm\) 7.50 \\ Greco di Tufo November (GRC-28) & 8.65 \(\pm\) 0.75 & 22.36 \(\pm\) 2.10 & 95.63 \(\pm\) 9.51 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Polyphenol concentrations in _Vitis vinifera_ ’Aglianico’ and 'Greco di Tufo’ leaves (mg/g of leaf powder extract) after MAE with different solvents and extraction conditions. Ethanol extract (EtOH), methanol:water extract 70:30 (MeOH:H\({}_{2}\)O), water (H\({}_{2}\)O) extract.  
August collection, suggesting that leaves remaining on the vine after the harvest could be promising as an inexpensive source of antioxidants.