## 6 Carotenoids  
Carotenoids, which can be divided into caroten (e.g., \(\beta\)-carotene and lycopene) and xanthophylls (e.g., lutein and zeaxanthin), are potent antioxidants and have various functions in human health, such as pro-vitamin A activity, cancer-preventing properties, and improvements in cognitive function as well as eye and cardiovascular health [8,11]. Immunomodulation activities and prevention of degenerative diseases have also been reported as possible health benefits of carotenoids [80]. In plants, these yellow and orange pigments take part in photosynthesis by protecting photosystems [78]. The level of total carotenoids is often approximated by measuring the absorbance of the acetone extract with a 470 nm wavelength. Conversion calculations depend on the solvent used and whether the calculation focused on the amount of chlorophyll in the extract. Some protocols describing the determination of chlorophyll also include the determination of total carotenoids [69,76]. The total carotenoid content measured in the biomass of various halophytes are summarised in Table 4. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Plant Species** & **Solvent** & **Method** & **Concentration** & **Unit** & **Ref.** \\ \hline _Arthroenenum macrostachyum_ & Acetone & & 210 \(\pm\) 10 & mg/100 gDM & [6] \\ \hline _Aster triplium_ & Ethanol & & \(\sim\)8 & mg/cm\({}^{2}\) & [68] \\ \hline _Halimine portulacoides_ & Acetone & & 51.47 \(\pm\) 17.76 & \(\mu\)g/gFW & [67] \\ \hline _Ipomoa pes-caprae_ & Acetone (90\%) & & 0.61 \(\pm\) 0.01 & mg/g & [34] \\ \hline _Mesembryanthemum nodifforum_ & Methanol & Spectrophotometry & \(\sim\)-21 & mg/100 gDM & [32] \\ \hline _Pluchen Inteculata_ & Acetone (90\%) & & 0.07 \(\pm\) 0.02 & mg/g & [34] \\ \hline _Salicornia bigelovii_ & Hexane & & 159.0 \(\pm\) 5.74 & mg/kgFW & [22] \\ \hline _Salicornia brachiata_ & Acetone & & 433.8 \(\pm\) 46.0 & \(\mu\)g/gDM & [77] \\ \hline _Salicornia europaea_ & Acetone & & \(\sim\)0.43 & mg/gFW & [73] \\ \hline _Salicornia neeri_ & Methanol & HPLC & 28.71 \(\pm\) 7.52 & \(\mu\)g/gDM & [78] \\ \hline _Salicornia persica_ & Acetone & & \(\sim\)0.44 & mg/gFW & [73] \\ \hline _Salicornia prostrata_ & Acetone & & 54.5 & \(\mu\)g/gFW & [63] \\ \hline _Salicornia runnessisima_ & Acetone & & -0.25 & mg/gFW & [79] \\ \hline \multirow{3}{*}{_Salicornia runnessisima_} & Ethyl acetate & HPLC & 3.49 & mg/100 gFM & [5] \\ \cline{2-5}  & Acetone & & 290 \(\pm\) 20 & mg/100 gDM & [6] \\ \hline \multirow{3}{*}{_Salvatora persica_} & Acetone (90\%) & & 0.84 \(\pm\) 0.02 & mg/g & [34] \\ \cline{2-5}  & DMF & & 11.4 \(\pm\) 2.5 & \(\mu\)g/100 gDM & [84] \\ \hline \multirow{3}{*}{_Sarxocornia fraticosa_} & Methanol & & \(\sim\)-16 & mg/100 gDM & [32] \\ \cline{2-5}  & Acetone & & 56.6 & \(\mu\)g/gFW & [63] \\ \cline{2-5}  & Acetone & & 34.76 \(\pm\) 9.03 & \(\mu\)g/gFW & [67] \\ \hline _Sarxocornia perenmis_ & Acetone & Spectrophotometry & 280 \(\pm\) 10 & mg/100 gDM & [6] \\ \hline _Suaeda fraticosa_ & Acetone (90\%) & & 0.56 \(\pm\) 0.01 & mg/g & [34] \\ \hline _Sueda marritina_ & Methanol & & \(\sim\)-12 & mg/100 gDM & [32] \\ \hline _Sueda prostrata_ & Acetone & & \(\sim\)-0.19 & mg/gFW & [79] \\ \hline _Tamarix gallica_ & Acetone & & \(\sim\)-70 & mg & [70] \\ \hline _Trespesia populnea_ & Acetone (90\%) & & 0.72 \(\pm\) 0.02 & mg/g & [34] \\ \cline{2-5}  & DMF & & 233.5 \(\pm\) 5.3 & mg/100 gDM & [85] \\ \hline \end{tabular}
\end{table} 
Table 4: Total carotenoid content measured from halophyte biomass. All studies measured the absorbance with 470 nm, except [PERSON] et al. [34], who used the method by [PERSON] and [PERSON] [81]; [PERSON] et al. [63], who used the method by [PERSON] et al. [82]; [PERSON] et al. [26], who used the same method as [PERSON] et al. [83]; and [PERSON] et al. [84] and [PERSON] et al. [85] who used N, N–dimethylformamide (DMF) as a solvent with the method by [PERSON] et al. [86]. The conversion calculations may differ. [PERSON] et al.