Pulicaria undulata (L.) C. A. Mey has multiple uses as part of the traditional medicament, and several biological activities of the plant have been corroborated in the scientific literature. The current work evaluates the phytochemical constituents and biological properties of the water-ethanol extract of the P. undulata growing in Qassim, the central arid regions of the Kingdom of Saudi Arabia. Qualitative UPLC-ESIQ-TOF analysis identified 27 compounds belonging to the phenolics, flavonoids, triterpenes, coumarins, and of fatty acids chemical classes. The quantitative analysis exhibited 33.3 mg/g GAE (Gallic Acid Equivalents), and 10.8 mg/g QE (Quercetin Equivalents) of the phenolics and flavonoids in the plant's concentrated (to dryness) water-ethanol extract. The trace elements analysis of the plant's dry powder established the presence of copper (20.13 µg/kg), and zinc (68.2 µg/kg) in the higher levels of occurrences. In terms of the antioxidant potential of the plant's extract, the ferric-reducing, and free-radicals scavenging activities were recorded at 47.11 mg/g, and 19.13 mg/g equivalents of the concentrated to dryness water-ethanol extract of the plant. The water-ethanol extract of P. undulata also exhibited antimicrobial activity against the tested Gram-positive bacteria, while no activity was observed against the tested Gram-negative bacteria, or the fungi. The MIC (minimum inhibitory concentration) values were in the range of 49 to 1563 µg/mL, whereas the MBC (minimum bactericidal concentration) values ranged from 49 to 3125 µg/mL, against the tested Gram-positive bacteria. The P. undulata water-ethanol extract also exhibited potent cytotoxic effects with the IC50 value at 519.2 µg/mL against the MCF-7 breast cancer cell-lines, followed by the anticancer activity of erythroleukemic cell-lines, K562 at 1212 µg/mL, and pancreatic cell-lines, PANC-1, at 1535 µg/mL, as compared to the normal fibroblast cells (4048 µg/mL). The Annexin-V assay demonstrated that, as the P. undulata extract's dose increased from IC50 to twice of the IC50, the percentage of the necrosis was found to be increased in the late apoptosis stage of the cancer cells. These data confirmed the P. undulata extract's ability to inhibit several human cancer cell lines' growth in comparison to other local halophytes. The antimicrobial activity of the plant was also confirmed.
Keywords: Annexin V; K562; MCF-7; PANC-1; Pulicaria undulata; anticancer; antimicrobial; antioxidant; flavonoids; phenolics.