## 1 Introduction
### Halophytes as Crop Plants  
For agricultural sustainability under saline conditions, two possible approaches are needed: (i) improving salt tolerance of cultivated crops, or (ii) domestication of halophytes [5]. The majority of crop plants are non-halophytes. Genetically modified crops have been developed for biosaline agriculture, but this is time consuming and involves many genes possessing various pros and cons and causes various allergic reactions, disrupting natural gene flow and increasing the risk factors of human diseases [7].  
The cultivation of halophytes for food, fodder, edible oil, biofuel, and medicine seems to be an alternate option, as they are fully equipped with better salt tolerance properties. Many species of halophytes have the potential to be used as gourmet vegetables and salad, i.e., _Aster tripolium_, _Atriplex hotensis_, _Beta maritime_, _Crambe maritiima_, _Crichum maritium_, _Inula crithmoides_, _Salicornia_ spp., _Salsola soda_, and _Tetragonia tetragonioides_. Some wild edible halophytes are in the genera _Bassia_, _Beta_, _Cakile_, _Chemopolatum_, _Plantago_, _Portulaca_, and _Suada_. _Atriplex hulinus_, _Salicornica fruticosa_, and _Cakile maritime_ accumulate Na\({}^{+}\) in their leaves, but the content of this ion is lower compared to other culinary halophytes. These plants can be used as sources of green salt (plant-based salt contains 50 % less Na than common salt) due to their nutritional value [8; 9]. The seeds and lignocellulosic biomass of several halophyte genera, i.e., _Salicornia_, _Suada_, _Atriplex_, _Distchlis_, and _Batis_, have been exploited for the production of biofuel (bioethanol). _Suada_ is a high salt tolerant C4 species. This genus ameliorates contaminated saline soil and is also used in food, fodder, medicine, and bioenergy.  
A wide group of halophyte species (2500-3000) occur naturally in salt marshes, providing an opportunity to use them as crop plants to combat food security in the future. Seven species of plants, namely _Suada glauc_, _Bassia scoparia_, _H. glomeratus_, _Kalidium foliatum_, _Medicago falcata_, _Atriplex canescens_, and _Artemisia desertorum_, can be used as enrichment materials for Zn and Cu. _H. glomeratus_ has medicinal value in traditional Chinese medicine. [PERSON] et al. [10] identified secondary metabolites that included flavones, flavonoids, flavandiols, glucosinolates, isqouinolines, pyridines, indoles, amino acids, lipids, carbohydrates, and ATP-binding cassette transporters. These metabolites regulate osmotic adjustment and modulate the adjustment of membrane lipid action in _H. glomeratus_. These metabolites also have applications in human cardiovascular diseases, cancers, diabetes, and heart diseases. Economic importance of some halophytes are listed below in Table 1.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Species** & **Secondary Metabolites** & **Economic Value** & **Reference** \\ \hline _Apocyanin venture_ & Flavonoids & Anti-inflammatory activity & [11] \\ _Atriplex triangularis_ & Hydroxycedysone, flavonoids, and phenolics & Nutritional properties rich source of proteins, vitamin A, and vitamin C & [12] \\ _Avicannia marina_ & Saponin, triterpenenoid, or phytosterol. & As fodder, biological and pharmacological importance & [13] \\ _Beta vulgaris_ & Phenolics, carotenoid, ascorbic acid, betalains & food additive, improve redness in tomato paste and jellies & [14] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Economically important halophytes, their bioactive metabolites, and their role in plants and humans