Comparative metabolomics of the different fractions of two saltwort (Salsola L.) species in relation to their anti-inflammatory activity

Abstract

Many of the plants of genus Salsola are edible halophytes which are known for their use in treatment of inflammation as well as their nutritional content. This study aims at comprehensive chemical profiling of two Salsola species that are widely distributed in arid areas; S. imbricata and S. jordanicola, using UHPLC-QqQ-MS in an attempt to decipher the bioactive constituents of the aerial parts of the selected plants and their ex-vivo anti-inflammatory activity. 73 chromatographic peaks were annotated where phytosterols dominated the metabolites in S. imbracta while phenylalkylamines were the major constituents detected in S. jordanicola. OPLS-DA model coefficients plot indicated that tetradecanoic acid, beta sitosterol and pentacosane were positively correlated to discrimination of S. imbricata species while N-feruloyloctopamine, N-feruloyltyramine, and ferulic acid, were positively correlated to discrimination of S. jordanicola species. Meanwhile, fractions of S. imbracta, reduced the 5 upregulation of TNF-α caused by LPS to levels lower than those produced by piroxicam while the petroleum ether and n-butanol fraction of S. jordanicola were more effective than piroxicam in reducing IL-6 gene expression. The coefficients plot depicted that methyl palmitate, aegicin, cleomiscoside, beta sitosterol and sitostanol possessed strong positive correlation to the down regulation of the pro-inflammatory marker TNF-α, IL-1β and IFN-γ while only norepinephrine derivatives were the major metabolites that showed strong positive correlation to the inhibition of IL-6 pro-inflammatory marker. The results obtained may help to explain chemically, the potential anti-inflammatory effect of the various Salsola species fractions increasing the value of the Salsola species as a putative functional foods.