## 3 Results and Discussion
### Phytochemical Characterization and Bioactivity
#### 3.3.1 Composition in Individual Phenolic Compounds  
In the halophytes, the tentatively identified phenolic compounds were classified into different classes of phenolic acids (hydroxycinnamic and hydroxybenzoic acids), flavonoids (flavones, flavanals, flavonoids, and flavanones), and hydrolysate tannins (gallotannins). These compounds exert potential antioxidant, anti-inflammatory, anti-carcinogenic [70; 71], anti-microbial [72], and inhibitory activity in key enzymes associated with, neurodegenerative diseases, e.g., Alzheimer's disease (e.g., acetylcholinesterase, AChE and butylcholinesterase, and BuChE), diabetes _melitius_ type 2 (\(\alpha\)-amylase and \(\alpha\)-glucosidase), and skin hyperpigmentation/food oxidation (tyrosinase) [73]. The qualitative and quantitative abundance of phenolic compounds in the halophytes is dependent on several factors, such as the environmental growth conditions and the analyzed species. Despite the existent amount of collected information in the plant database for the halophyte and salt-tolerant plants [74], the data regarding their phenolic composition remains limited, which compromises qualitative and quantitative data comparison. The study herein aims to fill the gap of knowledge, describing the phenolic composition of different halophyte species grown under the same soilless cultivation conditions. In the halophytes studied herein, 46 of the 94 tentatively identified compounds were hydroxycinnamic acids [75], mostly derivatives of caffe acid (Figure A1A), ferulic acid (Figure A1B), _p_-comumeric acid (Figure A1C), and sinapic acid (Figure A1D), showing thetypical molecular ion [M\(-\)H]\({}^{-}\) at \(m/z\) 179 (compounds **5**, **8**, **11**, **15**, **20**, **21**, **30**, **32**, **61**, **67**, **74**, **80**, **81**, **84**, and **86**), \(m/z\) 193 (compounds **18**, **19**, **22**, **24**, **29**, **40**, **43**, **89**, **90**, and **94**), \(m/z\) 163 (compounds **1**, **12**, **13**, **23**, **34**, **38**, **39**, **41**, **44**, **47**, **54**, **56**, **62**, **66**, **71**, **75**, **77**, **78**, **88**, and **93**), and \(m/z\) 223 (compound **26**) in the corresponding mass fragmentation spectra, Table A1--Appendix A. The presence of these hydroxycinnamic acid derivatives was previously reported in _S. ramossissima_[76], in conventional and microwave _S. ramossissima_ extracts [77], as well as in other halophyte plants such as _Glaux maritima_ roots [78], and in _C. maritium_[79], as a survival molecular adaptation to saline soil conditions, as described by [PERSON] et al. [78]. As shown in Table A1, there was high qualitative diversity in the phenolic composition of the different studied halophyte plants, with some compounds, such as the fertile acid derivatives being mostly detected in the _S. ramossissima_, _D. crassifolium_, _I. crithmoides_, _M. nodiforum_, and _M. crystallizationum_, but not in the _S. fruticosa_ and _C. maritium_ species. Considering the quantified amounts of hydroxycinnamic acids in the different halophyte species, Table 6 and Table S1--Supplementary Materials, _S. ramossissima_ stood out as the species with the highest content of hydroxycinnamic acids, namely, caffeic acid derivatives, such as 3,4-, 3,5-, and 4,5-dicaffeoylquinic acids (compounds **61**, **67**, and **74**) and caffeoylhydrocaffeoyl quinic acid (compound **80**). These compounds were also described in _S. europaea_ extracts [80], inhibiting the accumulation of cholesteryl ester hydroperoxide (CE-OOH) and therefore the blood plasma oxidation and the atherosclerotic plaques [81]. _C. maritium_ is highlighted from the remaining species as the one with the highest chlorogenic acid content (compound **15**) [82], Table S1--Supplementary Materials. In the same way, _S. fruticosa_ had the highest content of chlorogenic acid (compound **15**) content, and a similar amount (13.661 \(\upmu\)g/g FW) was reported for _Sarcocornia perennis alpini_ (12.240 \(\upmu\)g/g FW) [83]. In addition to the high chlorogenic acid content, _C.