## 2 Materials and Methods
### Chemical Characterisation of Pinus spp. Bark Polar Extracts  
#### 3.2.1 Qualitative Analysis  
The compounds present in the _P. pinaster_ Ait. and _P. pinea_ L. bark polar extracts were identified by UHPLC-DAD-MS\({}^{n}\). Table 3 lists the retention time, maxima UV wavelengths, the [M\(-\)H]\({}^{-}\) ions, and the MS\({}^{n}\) product ions of the 15 compounds (Figure 1) identified in the studied polar extracts. In addition to quinic acid (**1**), 14 phenolic compounds were found in the studied _Pinus_ spp. barks, such as protocatechuic acid (**2**), 10 flavan-3-ols (**3**-**12**), 2 flavononols (**13**-**14**), and a flavonol, i.e., quercetin (**15**). The identification of these compounds was performed by comparing the obtained spectroscopic results with the literature data and with those of the available commercial standards injected under the same experimental conditions, as discussed below. \begin{table}
\begin{tabular}{c c c c c} \hline \hline _Pinus_ spp. **by-Product** & **TPC (g GAE kg\({}^{-1}\) dw)** & **TPC (mg GAE g\({}^{-1}\) of Extract)** & **PC (g PAC kg\({}^{-1}\) of Extract)** & **PC (mg PAC g\({}^{-1}\) of Extract)** \\ \hline _P. pinaster_ Ait. bark & 116 \(\pm\) 11 & 539 \(\pm\) 26 & 174 \(\pm\) 12 & 814 \(\pm\) 58 \\ _P. pinea_ L. bark & 103 \(\pm\) 9 & 568 \(\pm\) 12 & 157 \(\pm\) 18 & 857 \(\pm\) 50 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Total phenolic content (TPC) and proanthocyanidin content (PC) of _Pinus pinaster_ Ait. and _Pinus pinea_ L. bark polar extracts. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**No. ** & **RT (min)** & **Compound** & \(\lambda_{\textbf{max}}\) **(mm)** & **[M –H]– (m/z)** & **MS* Product Ions (un/z and Relative Intensity (\%))** & **Reference** \\ \hline
1 & 0.66 & Quinic acid & 244, 279, 300 (sh) 1  & 191 & MS\({}^{2}\); 173 (15), 127 (0.4), 111 (100), 93 (1), 85 (2) & [13] \\
2 & 2.36 & Protocatechuric acid & 277, 259, 283 & 153 & MS\({}^{2}\); 153 (13), 135 (12), 121 (0), 100 (9), 95 (0.1) & Co 3  \\
3 & 3.22 & B-type (ep)catch trimer isomer 1 & 230, 279 & 865 & \({}^{3}\)S\({}^{2}\) (25), 79 (100), 73 (25), 69 (15), 69 (23) & [47,48] \\  & & & & & 575 (50), 533 (40), 400 (26), 353 (47) & [47,48] \\
4 & 5.78 & B-type (ep)catch trimer isomer 1 & 232, 278 & 577 & MS\({}^{2}\); 599 (45), 451 (100), 425 (98), 497 (23), 229 (25), & [21,47,48] \\  & & & & & 287 (24), 85 (203), 203 (2), 179 (2) & [21,47,48] \\  & & & & & MS\({}^{2}\); 559 (31), 451 (00), 425 (100), 425 (100), 427 (3), 228 (28), & [21,47,48] \\
5 & 6.20 & B-type (ep)catch trimer isomer 2 & 232, 278 & 577 & MS\({}^{2}\); 245 (100), 255 (203), 203 (17) (23) & [21,47,48] \\  & & & & & MS\({}^{2}\); 217 (25), 45 (100), 253 (203), 203 (17) & [23,17,29] \\
6 & 6.75 & B-type (ep)catch trimer isomer 3 & 232, 278 & 577 & MS\({}^{2}\); 599 (45), 451 (100), 425 (90), 400 (26), 298 (25) & [47,48] \\
8 & 7.15 & B-type (ep)catch trimer isomer 2 & 231, 278 & 865 & MS\({}^{2}\); 847 (57), 739 (100), 695 (15), 577 (29), 575 (21), & [47,48] \\  & & A-type & & & MS\({}^{2}\); 573 (18), 563 (32, 55), 498 (2), 465 (5), 439 & [50] \\  & & & & & MS\({}^{2}\); 847 (53), 799 (100), 695 (15), 577 (29), 575 (21), & [47,48] \\
9 & 7.51 & (ep)glallocatechin-(ep)catch trimer & 232, 281 & 591 & MS\({}^{2}\); 573 (18), 563 (32, 55), 59 (48), 492 (45), 439 & [50] \\  & & & & & MS\({}^{2}\); 100 (34), 32 (31), 32 (37) & [23,10] \\  & & & & & MS\({}^{2}\); 847 (23), 799 (213), 69 (59), 677 (32* Flavan-3-ols  
Based on the characteristic UV absorption spectra, the corresponding [M\(-\)H]\({}^{-}\) ions and respective MS\({}^{n}\) fragmentations (Table 3), catechin (**6**), 4 B-type (epi)catechin dimers (**4**, **5**, **7**, and **12**), 4 B-type (epi)catechin trimers (**3**, **8**, **10**, and **11**), and an A-type (epi)galactechin-(epi)catechin dimer (**9**) were identified in the analysed _P. pinaster_ Ait. and _P. pinac_ L. barks, as thoroughly described below.