A First Approach for the Micropropagation of the Edible and Medicinal Halophyte Inula crithmoides L.

Inula crithmoides L. (golden samphire) is an edible aromatic halophyte species with confirmed nutritional and medicinal properties attributed to the presence of important metabolites, including proteins, carotenoids, vitamins, and minerals. Therefore, this study aimed at establishing a micropropagation protocol for golden samphire that can serve as a nursery approach to its standardized commercial cultivation. For that purpose, a complete regeneration protocol was developed by improving shoot multiplication from nodal explants, rooting, and acclimatization methodologies. The treatment with BAP alone induced the maximum shoot formation (7-7.8 shoots/explant), while IAA treatment increased the shoot height (9.26-9.5 cm). Furthermore, the treatment that coupled best shoot multiplication (7.8 shoots/explant) and highest shoot height (7.58 cm) was MS medium supplemented with 0.25 mg/L BAP. Moreover, all shoots produced roots (100% rooting), and multiplication treatments did not exert significant effect on root length (7.8-9.7 cm/plantlet). Moreover, by the end of the rooting phase, plantlets cultivated with 0.25 mg/L BAP had the highest shoot number (4.2 shoots/plantlet), and plantlets from 0.6 mg/L IAA + 1 mg/L BAP presented the highest shoot height (14.2 cm) similar to control plantlets (14.0 cm). The survival up to the ex-vitro acclimatization stage was increased from 9.8% (control) to 83.3%, when plants were treated with a paraffin solution. Nevertheless, the in vitro multiplication of golden samphire is a promising way for its rapid propagation and can be used as a nursery method, contributing to the development of this species as an alternative food and medicinal crop.

A first approach for the micropropagation of the medicinal halophyte Polygonum maritimum L. and phenolic profile of acclimatized plants.

Polygonum maritimum L. (sea knotgrass) belongs to a genus commonly used in folk medicine to treat inflammation-related disorders. In vitro pharmacological studies have confirmed these properties that were ascribed to bioactive flavonoids, such as myricetin and quercetin glycosides. Therefore, this study aimed at establishing a micropropagation procedure for sea knotgrass for obtaining standardized materials for its potential commercial cultivation. For that, a complete plant regeneration protocol was developed by improving shoot multiplication from nodal explants, rooting and acclimatization procedures, followed by the assessment of the phenolic profile of the in vitro-produced plants. The combination of 3 mg/L 6-benzylaminopurine (BA) + 0.1 mg/L indole-3-acetic acid (IAA) induced the maximum shoot formation (10.3), which was significantly increased from the first to the second cycle (18.3). The best rooting capacity was observed on shoots derived from the control medium (100%), followed by 2 mg/L kinetin (KIN) (97%) and 3 mg/L BA + 0.1 mg/L IAA (90%); however, the shoot number at the end of the rooting phase was higher on shoots derived from 3 mg/L BA + 0.1 mg/L IAA (6.16). The plant growth regulators used in the multiplication phase influenced survival in the acclimatization process, and plants derived from the control medium had the highest survival percentage (63.1%). Acetone extracts made from aerial organs of micropropagated sea knotgrass showed a predominance of the flavonoid myricetin-3-O-rhamnoside (8.135 mg/g). Overall, the halophyte sea knotgrass was successfully micropropagated showing its potential as a medicinal crop for the extraction of bioactive molecules.

Application of In Vitro Plant Tissue Culture Techniques to Halophyte Species: A Review.

Halophytes are plants able to thrive in environments characterized by severe abiotic conditions, including high salinity and high light intensity, drought/flooding, and temperature fluctuations. Several species have ethnomedicinal uses, and some are currently explored as sources of food and cosmetic ingredients. Halophytes are considered important alternative cash crops to be used in sustainable saline production systems, due to their ability to grow in saline conditions where conventional glycophyte crops cannot, such as salt-affected soils and saline irrigation water. In vitro plant tissue culture (PTC) techniques have greatly contributed to industry and agriculture in the last century by exploiting the economic potential of several commercial crop plants. The application of PTC to selected halophyte species can thus contribute for developing innovative production systems and obtaining halophyte-based bioactive products. This work aimed to put together and review for the first time the most relevant information on the application of PTC to halophytes. Several protocols were established for the micropropagation of different species. Various explant types have been used as starting materials (e.g., basal shoots and nodes, cotyledons, epicotyls, inflorescence, internodal segments, leaves, roots, rhizomes, stems, shoot tips, or zygotic embryos), involving different micropropagation techniques (e.g., node culture, direct or indirect shoot neoformation, caulogenesis, somatic embryogenesis, rooting, acclimatization, germplasm conservation and cryopreservation, and callogenesis and cell suspension cultures). In vitro systems were also used to study physiological, biochemical, and molecular processes in halophytes, such as functional and salt-tolerance studies. Thus, the application of PTC to halophytes may be used to improve their controlled multiplication and the selection of desired traits for the in vitro production of plants enriched in nutritional and functional components, as well as for the study of their resistance to salt stress.

Metabolomic Profile and Biological Properties of Sea Lavender (Limonium algarvense Erben) Plants Cultivated with Aquaculture Wastewaters: Implications for Its Use in Herbal Formulations and Food Additives.

Water extracts from sea lavender (Limonium algarvense Erben) plants cultivated in greenhouse conditions and irrigated with freshwater and saline aquaculture effluents were evaluated for metabolomics by liquid chromatography-tandem high-resolution mass spectrometry (LC-HRMS/MS), and functional properties by in vitro and ex vivo methods. In vitro antioxidant methods included radical scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric-reducing antioxidant power (FRAP), and copper and iron chelating assets. Flowers' extracts had the highest compounds' diversity (flavonoids and its derivatives) and strongest in vitro antioxidant activity. These extracts were further tested for ex vivo antioxidant properties by oxidative haemolysis inhibition (OxHLIA), lipid peroxidation inhibition by thiobarbituric acid reactive substances (TBARS) formation, and anti-melanogenic, anti-tyrosinase, anti-inflammation, and cytotoxicity. Extract from plants irrigated with 300 mM NaCl was the most active towards TBARS (IC50 = 81 µg/mL) and tyrosinase (IC50 = 873 µg/mL). In OxHLIA, the activity was similar for fresh- and saltwater-irrigated plants (300 mM NaCl; IC50 = 136 and 140 µg/mL, respectively). Samples had no anti-inflammatory and anti-melanogenic abilities and were not toxic. Our results suggest that sea lavender cultivated under saline conditions could provide a flavonoid-rich water extract with antioxidant and anti-tyrosinase properties with potential use as a food preservative or as a functional ingredient in herbal supplements.

A Review on Sarcocornia Species: Ethnopharmacology, Nutritional Properties, Phytochemistry, Biological Activities and Propagation.

Sarcocornia A. J. Scott is a halophytic edible succulent plant belonging to the Amaranthaceae family. To date, the genus includes 28 species distributed worldwide in saline environments, usually salt marshes. Sarcocornia (Scott) is similar to Salicornia (L.), which has a recognized commercial value in morphological and taxonomical traits. Species of both genera are commonly named samphire or glassworts in Europe, and their fleshy shoots are commercialized under their traditional names. Due to their nutritional, organoleptic and medicinal properties, Sarcocornia species have a high economic potential in various biotechnology sectors. Being highly tolerant to salt, they can be cultivated in saline conditions, and dissimilar to Salicornia, they are perennial, i.e., they can be harvested year-round. Therefore, Sarcocornia species are considered promising gourmet vegetables to be explored in the context of climate change, soil and water salinization and eco-sustainability. We hereby put together and reviewed the most relevant information on Sarcocornia taxonomy, morphology, nutritional and pharmacological properties, uses in ethnomedicine, potential applications in biotechnology, and propagation strategies.

Nutritional and Functional Evaluation of Inula crithmoides and Mesembryanthemum nodiflorum Grown in Different Salinities for Human Consumption.

The nutritional composition and productivity of halophytes is strongly related to the biotic/abiotic stress to which these extremophile salt tolerant plants are subjected during their cultivation cycle. In this study, two commercial halophyte species (Inula crithmoides and Mesembryanthemum nodiflorum) were cultivated at six levels of salinity using a soilless cultivation system. In this way, it was possible to understand the response mechanisms of these halophytes to salt stress. The relative productivity decreased from the salinities of 110 and 200 mmol L-1 upwards for I. crithmoides and M. nodiflorum, respectively. Nonetheless, the nutritional profile for human consumption remained balanced. In general, I. crithmoides vitamin (B1 and B6) contents were significantly higher than those of M. nodiflorum. For both species, ß-carotene and lutein were induced by salinity, possibly as a response to oxidative stress. Phenolic compounds were more abundant in plants cultivated at lower salinities, while the antioxidant activity increased as a response to salt stress. Sensory characteristics were evaluated by a panel of culinary chefs showing a preference for plants grown at the salt concentration of 350 mmol L-1. In summary, salinity stress was effective in boosting important nutritional components in these species, and the soilless system promotes the sustainable and safe production of halophyte plants for human consumption.

In vitro enzyme inhibitory and anti-oxidant properties, cytotoxicity and chemical composition of the halophyte Malcolmia littorea (L.) R.Br. (Brassicaceae).

This work reports for the first time the in vitro anti-oxidant (towards DPPH, ABTS, copper and iron), enzymatic inhibitory (on AChE, BuChE, α-glucosidase, α-amylase and tyrosinase), cytotoxicity (towards HepG2 and HEK 293 cells), and metabolomics (by HPLC-MS) of extracts from organs of Malcolmia littorea (L.) R.Br. Extracts were constituted mainly by phenolic acids and flavonoids, and main compounds were salicylic acid and luteolin-7-O-glucoside. Samples showed reduced radical scavenging and metal chelating capacity, and only the methanol extracts reduced iron. The root's ethanol and methanol extracts, and the aerial organ's ethanol extract exhibited the highest AChE inhibition. The root's ethanol extract displayed dual anti-cholinesterase activity. Samples showed a low capacity to inhibit α-amylase, but a high α-glucosidase inhibition was obtained with the root's and flower's ethanol extracts, and flower's methanol extract. Overall, samples displayed a high inhibition against tyrosinase, reduced HepG2 cellular viability and were less toxic towards HEK 293 cells.

Influence of cultivation salinity in the nutritional composition, antioxidant capacity and microbial quality of Salicornia ramosissima commercially produced in soilless systems.

The consumption of halophytes as healthy gourmet food has increased considerably in the past few years. However, knowledge on the nutritional profile of domesticated halophytes is scarce and little is known on which cultivation conditions can produce plants with the best nutritional and functional properties. In this context, Salicornia ramosissima J. Woods was cultivated in six different salt concentrations, ranging from 35 to 465 mM of NaCl. Both the nutritional profile, the antioxidant capacity, and microbial quality of the produced plants were evaluated including minerals and vitamins. Salt has a marked effect on growth, which decreases for salinities higher than 110 mM. Nonetheless, plants cultivated with intermediate levels of salinity (110 and 200 mM) revealed better antioxidant status with higher amounts of phenolic compounds. Overall, results from this paper indicated that soilless culture systems using low-intermediate salinities produces S. ramosissima plants fit for commercialization and human consumption.

Wild vs cultivated halophytes: Nutritional and functional differences.

Some halophyte plants are currently used in gourmet cuisine due to their unique organoleptic properties. Moreover, they exhibit excellent nutritional and functional properties, being rich in polyphenolics and vitamins. These compounds are associated to strong antioxidant activity and enhanced health benefits. This work compared the nutritional properties and antioxidant potential of three species (Mesembryanthemum nodiflorum, Suaeda maritima and Sarcocornia fruticosa) collected in saltmarshes from Portugal and Spain with those of cultivated plants. The latter were generally more succulent and had higher contents of minerals than plants obtained from the wild and contained less fibre. All species assayed are a good source of proteins, fibres and minerals. Additionally, they are good sources of carotenoids and vitamins A, C and B6 and showed good antioxidant potential particularly S. maritima. Chromatographic analysis of the phenolic profile revealed that ferulic and caffeic acids as the most relevant phenolic compounds detected in the halophytes tested.

Phenolic Profile, Toxicity, Enzyme Inhibition, In Silico Studies, and Antioxidant Properties of Cakile maritima Scop. (Brassicaceae) from Southern Portugal.

Cakile maritima Scop. (sea rocket) is an edible halophyte plant with several ethnomedicinal uses. This work reports the chemical profile and bioactivities of food grade extracts from sea rocket organs. Toxicity was determined on mammalian cells, and phenolic profiling and the quantitation of the main metabolites were made by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Enzymatic inhibition was determined towards acetyl- and butyrylcholinesterase (AChE, BuChE), α-glucosidase, α-amylase, and tyrosinase. Docking studies were performed to tyrosinase, on the major metabolites, and samples were tested for antioxidant properties. Extracts were not toxic, were constituted mainly by flavonoids, and some compounds (roseoside and oleuropein) are here described for the first time in the species. The aerial organs' ethanol extract had relevant activity towards 2,2-diphenyl-1-picrylhydrazyl [DPPH, half maximal inhibitory concentration (IC50) = 0.59 mg/mL], and ferric-reducing activity power (FRAP, IC50 = 0.99 mg/mL). All samples were more active towards AChE than on BuChE. The ethanol fruits' extract inhibited α-glucosidase [2.19 mmol of equivalent of acarbose (ACAE)/g]. Samples were active against tyrosinase, especially the aerial organs' ethanol extracts [25.9 mg of equivalent of kojic acid (KAE)/g]. Quercetin and kaempferol glycosides fit well into the enzymatic pocket of tyrosinase. Our results suggest sea rocket as a candidate to be further explored as a source of bioactive products.

Dataset on functional and chemical properties of the medicinal halophyte Polygonum maritimum L. under greenhouse cultivation.

This data article includes data and analyses on the effect of different agronomic techniques on the production of Polygonum maritimum L. (sea knotgrass), namely different salinity irrigation treatments (0, 100, 200, 300 and 600 mM of NaCl) and a multi-harvest regime, and their relation with the chemical profile (ultra-high-resolution mass spectrometry - UHRMS), in vitro antioxidant [radical-scavenging activity (RSA) of DPPH and ABTS, copper chelating activity and ferric reducing antioxidant power] and anti-inflammatory (nitric oxide reduction on lipopolysaccharide-stimulated macrophages) activities. For further interpretation of the data presented in this work, please see the related research article "The irrigation salinity and harvesting affect the growth, chemical profile and biological activities of Polygonum maritimum L." (Rodrigues et al., 2019).