Metabolomics and molecular networking studies to uncover the chemodiversity of three Pulicaria species in Qatar and their correlation with antioxidant and anticancer potential

Abstract

Qatari Pulicaria species-Pulicaria undulata (L.) C. A. Mey., Pulicaria sicula (L.) Moris and Pulicaria gnaphalodes (Vent.) Boiss have been a source of food and medicine among locals. However, these species have taxonomic issues and alternative uses. Hence, this study aimed to comparatively investigate the chemical diversity of three Qatari Pulicaria species, including their antioxidant and anticancer potential. HPLC-QTOF-MS-based untargeted metabolomics and molecular networking approaches were used to study the chemical diversity. The total phenolic and flavonoid contents, including antioxidant activity, were determined using standard colorimetric microplate-based assays. The anticancer activity was evaluated in human breast cancer MDA-MB-231 cells using the MTT assay. The methanolic extracts of three Pulicaria species had distinct chemical signatures, with a notable portion of similar compounds. Phytochemically, P. undulata and P. sicula were more similar to each other than P. gnaphalodes. Among the 36 compounds identified across all extracts, sesquiterpene lactones represented the most abundant chemical class. Interestingly, the methanolic extract of P. undulata was particularly qualitatively rich in sesquiterpene lactones, whereas P. sicula was comparatively richer in flavonoids, quantitatively. The observed antioxidant activity in P. sicula and P. undulata was nearly identical, despite P. sicula having significantly higher contents of total phenolics and flavonoids. The anticancer activity of extracts from all three species was dose-dependent, with P. undulata exhibiting the highest potency among them. This study provides valuable insights into the comparative chemodiversity and bioactivity profiles of three Pulicaria species, crucial for their quality control, and precise and sustainable use as anticancer or nutraceutical agents.