## 7 Vitamins
[93] studied the effect of salt stress on the \(\alpha\)-tocopherol content of glyophyte (_Arabidopsis thaliana_) and halophyte (_Cakile martiima_) species. They found the vitamin E content of glycophytes decreases by 50% soon after being exposed to salt, whereas the vitamin levels of halophyte plants remained significantly higher throughout the cultivation period. [PERSON] et al. [6] found high concentrations of \(\alpha\)-tocopherol in _Arthrocennium macrostachyum_ shoots, making it a good source of vitamin E, similarly to other green vegetables, such as kale and broccoli. The concentration of \(\alpha\)-tocopherol measured in halophyte biomasses is summarised in Table 6. Significant variations in vitamin E content are possible \begin{table}
\begin{tabular}{c c c c c c} \hline
**Plant Species** & **Solvent** & **Method** & **Concentration** & **Unit** & **Ref.** \\ \hline _Arthrocennium indicum_ & m-Phosphoric acid (4.5\%) & & 19.17 \(\pm\) 0.50 (C) & mg/100 gFW & [90] \\ \hline _Halacennium strobllacum_ & m-Phosphoric acid (4.5\%) & & 7.38 \(\pm\) 0.54 (C) & mg/100 gFW & [90] \\ \hline _Mesembranthennium nodiform_ & Ammonium acetate/methanol (50.50) & HPLC-PDA & \(\sim\)0.5 (C) & g/100 gDM & [32] \\ \hline _Salicornia bigdovii_ & Oxalic acid solution & Indophenol titration & 58.4 \(\pm\) 1.39 (C) & mg/kgFW & [22] \\ \hline _Salicornia ramossissima_ & Ammonium acetate/methanol (50.50) & HPLC-PDA & 30.4 \(\pm\) 2.0 (B1) & mg/100 gFW & [5] \\ \hline _Salvadora persica_ & Trichoroacetic acid (6\%) & Spectrophotometry & 68.0 \(\pm\) 15.9 (C) & mg/100 gDM & [84] \\ \hline _Sarxocornia fraticosa_ & Ammonium acetate/methanol (50.50) & HPLC-PDA & \(\sim\)1.0 (C) & g/100 gDM & [32] \\ \hline \multirow{4}{*}{_Suada aegyptiaca_} & Ammonium acetate/methanol (50.50) & HPLC-PDA & \(\sim\)10 (B6) & mg/100 gDM & [89] \\ \cline{2-5}  & & & 181 \(\pm\) 2.3 (B6) & mg/kg & \\ \cline{1-1} \cline{2-5}  & & & 118 \(\pm\) 2.2 (B9) & mg/kg & \\ \cline{1-1} \cline{2-5}  & & & 466 \(\pm\) 2.5 (B12) & mg/kg & \\ \hline _Suada fraticosa_ & m-Phosphoric acid (4.5\%) & HPLC-UV & 2.46 \(\pm\) 0.07 (C) & mg/100 gFW & [90] \\ \hline _Suada mattriima_ & Ammonium acetate/methanol (50.50) & HPLC-PDA & \(\sim\)3 (C) & g/100 gDM & [32] \\ \cline{2-5}  & & & \(\sim\)9.5 (B6) & mg/100 gDM & \\ \hline \multirow{4}{*}{_Suada vera_} & Ammonium & & 102 \(\pm\) 1.4 (B6) & mg/kg & \\ \cline{1-1} \cline{2-5}  & & & 118 \(\pm\) 2.2 (B9) & mg/kg & \\ \cline{1-1} \cline{2-5}  & & & 271 \(\pm\) 1.7 (B12) & mg/kg & \\ \hline _Thepsesia populina_ & Trichoroacetic acid (6\%) & Spectrophotometry & 44.3 \(\pm\) 5.5 (C) & mg/100 gDM & [85] \\ \hline \end{tabular}
\end{table} 
Table 5: Ascorbic acid (vitamin C) and thiamine, pyridoxine, folate, and cobalamin (vitamin B1, B6, B9, and B12, respectively) concentrations measured in halophyte biomasses. The analysed vitamin is marked in parentheses after its concentration. between species within the same genus, which can be seen in the reported results, for example, in _Sarcocornia_ and _Suaea_ species. Concerning another fat-soluble compound, retinyl acetate (vitamin A), [PERSON] et al. [32] found concentrations of 4.51 mg/100 gDM and 5.39 mg/100 gDM in _Mesembryanthemum nodiform_ and _Suaea matrituma_, respectively. No other studies were found to measure the vitamin A content in halophytes. However, the most important plant-based vitamin A intake for humans comes from the pro-vitamin A activity of carotenoids, mainly \(\beta\)-carotene [95]. Changes in environmental conditions influence plants, and some halophytes exhibit changes in their colour as an adaptation to the stress caused by high UV radiation, temperature, or salinity, factors which also affect the plants' chemical composition, as shown by [PERSON] et al. [90]. Studies have shown that the phenotypic stage (green or red-purple) has a significant effect on the ascorbic acid content of _Suaea fruticosa_ and the \(\alpha\)-tocopherol content of _Suaea fruticosa_ and _Arthocennium indicum_[90].