LC-MS untargeted metabolomic analysis of the halophyte Salsola tragus in the climate change scenario revealed a promising phytocomplex

Climate change causes higher temperatures, raised sea levels, and altered precipitation patterns. These phenomena influence with each other and lead to a vicious circle with many harmful environmental implications, including an increased soils salinization that determines serious consequences for agriculture, native vegetation, and ecosystems in general (1). It affects the plant growth by negatively influencing the nutrient uptake and by causing water stress. In this context, the interest in halophyte plants is significantly growing up. Halophytes are plant species suitable for living in environments with high concentrations of salinity, such as coastal areas or brackish basins, since they developed special mechanisms to tolerate salty soils or water which make them able to survive in environments where many other species would not be able to thrive (1). The genus Salsola, belonging to the family Amaranthaceae, includes about 120 halophyte species of herbaceous or shrubby plants, widespread especially in the brackish grounds of the moderate and subtropical regions of Europe, Asia, Africa, and North America (2,3). Salsola tragus L., commonly known as Russian thistle or tumbleweed, is a highly adaptable and fast-growing annual plant. It has an upright appearance and can reach a height between 30-120 cm. Its leaves are small, green, red, or striped with a cylindrical shape and a pointed tip. They are arranged alternately along the stem. The flowers are small, greenish or pinkish. Salsola species are well-known in folk Chinese and Russian medicine as anti-hypertensive, diuretic, anti-cancer, emollient, purgative, anti-ulcer, and anti-inflammatory plants. In continuing our study on halophyte plants belonging to Salsola genus (2), Salsola tragus L. was herein investigated. Despite its ecological resilience and ancient popular uses, few phytochemical studies on Salsola tragus L. are reported in the literature. Tetrahydroisoquinoline alkaloids (salsoline and salsolidine), fatty acids, and flavonoids (isorhamnetin derivatives) were previously found as constituents of this halophyte and its extracts were tested for the antioxidant activity (3). Tuscan coasts are rich in Salsola tragus L. plants, which were collected with the aim of carrying out for the first time an untargeted metabolomic study by UHPLC-HR-Orbitrap/ESI-MS analysis on the extracted phytocomplex. The raw material was dried in the oven at 40 °C, defatted with n-hexane, and subjected to dynamic maceration with methanol for three consecutive days. The methanol residue was injected into the LC-MS system for the chemical fingerprint study. A total of 15 compounds was tentatively identified by comparing retention times, HR full mass spectra, and fragmentation patterns with data reported in the literature and database, and considering a mass error < 5 ppm on the experimental molecular formula. The identified components were mainly quercetin, kaempferol and isorhamnetin mono/diglycosides, together with phenethylamine alkaloids (N-feruloyltyramine and N-feruloylmethoxydopamine) and fatty acids (malyngic acid, pinellic acid, and linoleic acid). In conclusion, qualitative analysis showed the occurrence of many flavonoid derivatives with proven health- promoting properties and a varied chemical profile. Particularly noteworthy are the two identified alkaloids which are reported in the literature for the anti-inflammatory effect and protective role against β-amyloid peptide-induced neurotoxicity. Salsola tragus L., thanks to its remarkable environment adaptability and chemical composition, is an interesting biomass from a botanical, agricultural and nutraceutical point of view encouraging future studies on its potential biological value. References 1) T. J. Flowers, A. Muscolo (2015) AoB Plants, 7, plv020 2) A. M. Iannuzzi, R. Moschini, M. De Leo, C. Pineschi, F. Balestri, M. Cappiello, A. Braca, A. Del-Corso (2020) Food Biosci., 37, 100713 3) M. R. Loizzo, R. Tundis, G. A. Statti, N. G. Passalacqua, L. Peruzzi, F. Menichini (2007) Nat. Prod. Res., 21, 846-851