Comparative Phytochemical Analysis of Five Species of the Genus <em>Arthrophytum</em> Schrenk (Amaranthaceae) from the Flora of Kazakhstan

This article presents the results of the first comparative phytochemical analysis of five species of the genus Arthrophytum Schrenk (Amaranthaceae Juss.) — A. lehmannianum Bunge, A. iliense Iljin, A. longibracteatum Korovin, A. subulifolium Schrenk, and A. betpakdalense Korovin &amp; Mironov — using gas chromatography–mass spectrometry (GC–MS). The genus Arthrophytum is a relict systematic group whose range is limited to the desert regions of Northern Turan. The largest number of representatives of the genus are concentrated in the geologically ancient Betpakdala Desert. All of them are narrowly endemic and stenotopic species growing in inaccessible habitats, which determines their rarity and, as a result, their understudied nature, including the virtual absence of data on their phytochemical composition. Meanwhile, the results of our research, which aimed to conduct a comparative phytochemical analysis of the five above-mentioned species of the genus Arthrophytum to detect and identify their chemical components (using gas chromatography-mass spectrometry (GC-MS)), demonstrated the value of their metabolite composition. The analysis showed that the studied taxa are characterised by a rich pool of isoprenoids, including terpenes, sterols, tocopherols and squalene, as well as lipid components of cuticular coatings — fatty acids and long-chain alcohols. It was found that isoprenoids dominate in all studied species, especially in A. subulifolium and A. longibracteatum. A. iliense is distinguished by a high content of carbonyl and aromatic compounds, while A. longibracteatum and A. lehmannianum are characterised by an increased content of fatty acids and long-chain alcohols. Common metabolites — β-sitosterol, stigmasterol, vitamin E, squalene, and carophyllene — form the conservative biochemical core of the genus. Thus, the results obtained for the first time demonstrate the chemotaxonomic and functional features of relict species of the genus Arthrophytum and open up prospects for their further study and use in the pharmaceutical, cosmetic, and aromatic industries.