## 3 Results and Discussion
### Phytochemical Characterization and Bioactivity
#### 3.3.1 Composition in Individual Phenolic Compounds
crystallization_ \\ \hline _TPC_ (mg CA/g/ FW) & 0.25 \(\pm\) 0.02 \({}^{\circ}\) & 0.33 \(\pm\) 0.02 \({}^{\circ}\) & 0.41 \(\pm\) 0.09 \({}^{\circ}\) & 0.11 \(\pm\) 0.007 \({}^{\circ}\) & 0.25 \(\pm\) 0.04 \({}^{\circ}\) & 0.098 \(\Regarding the hydroxybenzoic acids, based on the respective fragmentation mass pattern, in the studied halophyte plants, the main compounds were tentatively identified as derivatives of protocatechuric acid (\(m/z\) 153), gallic acid (\(m/z\) 169), and syringe acid (\(m/z\) 197), Figure A2--Appendix A. As described previously for the hydroxycinamic acids, in the halophyte species, there was also a huge qualitative diversity in the hydroxybenzoic acids composition. Unlike most halophytes, in the \(D\). _crasifolium_ and \(M\). _crystallinum_ species, none of the studied hydroxybenzoic acids were detected. The lower content of \(D\). _crasifolium_ and \(M\). _crystallinum_ species in salt showed a positive association with the absence of hydroxybenzoic acids in these plants. As described by [PERSON] et al. [78] and [PERSON] et al. [85], despite the plant's adaptive variability in salt environmental conditions, the phenolic compounds, particularly the phenolic acids, accumulate in the halophytes as a protective response against the oxidative stress imposed by the soil salinization; therefore, in the plants with lower salt content a lower phenolic content is expected. From a quantitative point of view, \(S.nmossisima\) showed the highest content of hydroxybenzoic acids, which is particularly thanks to the protocatechuric acid arabinoside (compound **9**) content, Table 6 and Table S1--Supplementary Materials. This compound was also detected in \(S\). _fruticosa_ in a lower amount. In \(C\). _mariimum_, the protocatechuric acid esterified to a glycoside moiety was the most abundant hydroxybenzoic acid compound. The quantification of the aglycone form of protocatechuric acid was made previously by [PERSON] et al. [78] for other halophytes, namely, _Spergularia marina_ (L) and _Glaux maritima_. In the studied halophyte plants, 35 compounds were classified as flavonoids. The most diverse flavonoids (Figures A3 and A4--Appendix A) belong to the flavones and flavonoids classes [86], which included 13 and 10 different compounds, respectively. The flavanol class included five tentatively identified compounds, and the remaining classes of flavanones and flavanonols comprised, respectively, six and one compounds, Table A1. The flavonoids, putatively identified in the halophytes, were derivatives of quercetin, [M\(-\)H]\({}^{-}\) at \(m/z\) 301, kaempfer, [M\(-\)H]\({}^{-}\) at \(m/z\) 285, and isorhamnetin, [M\(-\)H]\({}^{-}\) at \(m/z\) 315, esterified with sugar units (e.g., glucoside, rutinose, and robinobioside) in C3 of C ring, but also methylated forms of quercetin such as rhamnetin (compound **7**). The kaempfer derivative (compound **83**) was tentatively identified for the first time in these plants, based on the fragmentation pattern, with the presence of the fragment ion \(m/z\) 285 (kaempfer), \(m/z\) 593 (kaempfer lramnosyl glucosyl fragment), and \(m/z\) 739 (Kaempfer 3- glucosyl (1-3) rhamn (1-6) galactoside with -OH group loss) previously identified in _Cammellia sinensis_[87]. This flavonoids' class was the most abundant in the halophytes, particularly in \(S\). _fruticosa_, at the expense of isorhamnetin 3-O-robinobioside (compound **65**) and rhamnetin hexosyl pentoside (compound **59**), tentatively identified, for the first time in this species, based on the fragmentation pattern with fragment ions at \(m/z\) 315 (rhamnetin), \(m/z\) 477 (rhamnetin hexosyl), and \(m/z\) 609 (rhamnetin hexosyl attached to a pentose residue without -H\({}_{2}\)O group), and in \(C\). _mariimum_, owing to quercetin 3-O-rutinoside and quercetin 3-O-glucose (compounds **45** and **53**). In _D. _crasifolium_, the most abundant flavonoids were derivatives of isorhamnetin rutinoside (compound **58**) and isorhamnetin glucoside (compound **73**), and in \(M\).