## 3 Results and Discussion
### Spectroscopic Profile by ATR-FTIR  
Figure 1 shows an example of the ATR-FTIR spectra of the Aglianico and Greco di Tufo leaf extracts of in the region of 4000-650 cm\({}^{-1}\). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Spectral Ranges Analyzed with SIMCA** & \multicolumn{2}{c}{**Peak Wavelength (cm\({}^{-1}\))**} & \multicolumn{2}{c}{**Vibrational Mode**} \\ \hline  & \multicolumn{2}{c}{**Solvent**} & \\ \hline  & **Ethanol** & **Methanol–Water (70:30)** & **Water** & \\ \hline
3600–3000 & 3353- & 3322 & 3332 & OH and C-H stretch. \\ \hline
2999–2800 & 2961- & & & \\  & 2926- & 2932 & 2932 &
\begin{tabular}{c} CH\({}_{2}\) and CH\({}_{3}\) \\ stretching vibrations \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Vibrational mode of ‘Aglianico’ and ‘Greco di Tufo’ leaf extract spectra based on current literature. Range values of the peaks for ‘Aglianico’ and ‘Greco di Tufo’ harvested in October and November are reported. Figure 1: FTIR absorption spectrum ‘Aglianico’ (**A**) and ‘Greco di Tufo’ (**B**) leaf extract with EtOH (red line), MetOH:H\({}_{2}\)O (70:30) (black line), H\({}_{2}\)O (blue line). The measured absorbance spectrum reported was baseline corrected. Peaks are identified by numbers. The wavelength of the peak absorbance is indicated in Table 4.  
The spectrum contains several bands arising from the contribution of the vibrational mode of different functional groups. Vibrational mode and peak assignments are based on literature [30; 31; 32]. The bands reported in Table 4 are arbitrarily grouped in spectral ranges and analyzed by PCA statistical analysis (SIMCA). The broad peak present in all extracts around 3350-3320 cm\({}^{-1}\) is due to hydroxyl groups (-OH) stretching and could derive from the -OH of the ethanol. However, we dried the sample so the interference should be minimized. It is worth noting that phenolic compounds are characterized by the presence of -OH that resonates in this area. Indeed, the strong absorption with a wide and strong band centered at 3350 cm\({}^{-1}\) is assigned to the -OH and C-H, typical of the aromatic medium [33]. In the spectral range 3000-2800 cm\({}^{-1}\) there are three peaks in the EtOH extract, that are absent in the MetOH:H\({}_{2}\)O (70:30) and H\({}_{2}\)O extracts. They are likely due to -CH\({}_{2}\) and -CH\({}_{3}\) of lipids. In the range, 1750 and 1524 cm\({}^{-1}\), three well-resolved peaks can be seen in the ethanol extract (1721, 1655, and 1608 cm\({}^{-1}\)), while two peaks (1719-1720 and 1606 cm\({}^{-1}\)) are present in the methanol:water (70:30) and water extracts. The peak at 1720 cm\({}^{-1}\) could be due to carboxylic acid structures (C=O) stretching vibrations. In the literature, the hydroxybenzoic and hydroxycinnamic acids show carboxylic acid structures (C=O) stretching vibrations in the 1715-1680 cm\({}^{-1}\) region. Gallic acid (hydroxybenzoic acid) and caffe acid (carboxylic acid) are both present in Greco di Tufo leaf extracts [34]. The aromatic ring with six carbon atoms has links (C=C) which generate bands between 1625 and 1430 cm\({}^{-1}\)[35] and that in our case could correspond to the peak at 1608 cm\({}^{-1}\) of the ethanol extract and the peak at 1606 cm\({}^{-1}\) of the MetOH:H\({}_{2}\)O (70:30) and H\({}_{2}\)O extracts. Variations in the vibration frequencies of these bands have been reported by [PERSON] et al. (2017) [36] and could be due to the ortho-, meta-, and para- position of the substituents. The peak at 1655 cm\({}^{-1}\) of the ethanolic extract most likely corresponds to chlorophyll [37]. The range 1475-1171 cm\({}^{-1}\) is not highly resolved in the extracts with MeOH:H\({}_{2}\)O (70:30) and H\({}_{2}\)O, while it is best resolved with EtOH. This region is generally attributed to proteins, lipids, and nucleic acids. In this range, the ethanol allows a better discrimination MeOH:H\({}_{2}\)O (70:30) and H\({}_{2}\)O. The bands around 1263 cm\({}^{-1}\) were attributed to Rutin (flavonol) by [PERSON] et al. (2017) [38].