Lipids in halophyte seeds <i>Suaeda salsa</i> and <i>Halostachys caspica</i> and their biological activity

There has been a growing scientific interest in the use of biologically active compounds derived from halophytes. The study of lipids from these plants, which possess diverse beneficial properties and biological activities, is of significant practical importance for modern agriculture. Biopesticides developed from halophytic plants could serve as an effective and environmentally friendly alternative to synthetic options. In this context, the total lipids (TL), which include neutral lipids (NL), glycolipids (GL), and phospholipids (PhL), from <i>S. salsa</i> (L.) Pall fruit and the aboveground part of <i>H. caspica</i> C.A. Mey, were analyzed. These plants are found in medium and strongly saline lands in Uzbekistan. The total lipid content in the fruits of <i>S. salsa</i> is 2.93%; however, the share of polar lipids (PL) (glycolipids, phospholipids) in relation to TL is 20.8%. The lipids of the aboveground part of <i>H. caspica</i> contain a lower amount of TL-2.26%, and the PL make up almost 74% of the glycolipid mass. The fatty acid (FA) composition of <i>S. salsa</i> lipids revealed 18 to 20 different components, with neutral lipids (NL) predominantly consisting of 18:1n9 and 18:2n6. In glycolipids (GL), 16:0 and 18:0 were the most common fatty acids, while phospholipids (PhL) primarily featured 16:0, 18:1n9, and 18:2n6. All lipid groups contained linolenic acid (18:3n3) at concentrations ranging from 5.61% to 2.84%, and eicosadienoic acid (20:2n6) ranging from 2.02% to 1.10%, both of which are known for their increased biological activity. <i>H. caspica</i> fatty acids had 26 fatty acid components, with 16:0 and 18:1n9 being the most prevalent. Additionally, fatty acids 22:0 and 24:0 were present in quantities exceeding 10%. TL <i>S. salsa</i> has demonstrated significant insecticidal activity against <i>sitophilus oryzae</i> storage pest and various types of aphids: <i>Schizaphis graminum</i>, <i>Macrosiphum rosae,</i> and <i>Aphis pomi. In vitro</i> experiments revealed that TL <i>S. salsa</i> exhibited weak antifungal activity, while the lipids from <i>H. caspica</i> displayed moderate antifungal activity against the phytopathogens <i>F. oxysporum</i> and <i>F. solani</i>. An important result was the discovery of a synergistic effect in the antifungal activity of total lipids from <i>S. salsa</i> and <i>H. caspica</i> when combined in a 1:1 ratio. This combination demonstrated significantly higher antifungal activity than either component used alone. This enhancement can be attributed to the mixture of lipids derived from different organs of halophytic plants, which contain fatty acids of varying chain lengths and degrees of unsaturation. Such diversity is likely more effective in causing structural changes in the cell membranes of pathogenic fungi, thereby disrupting their functions. The data obtained present new opportunities for developing biopesticide products based on the lipids from <i>S. salsa</i> and <i>H. caspica</i> for agricultural use.