Comparative analysis of bioactivities of leaf extracts from wild plant species Verbascum sinuatum, Amaranthus spinosus, Carduus getulus, and Heterotheca subaxillaris collected in Gaza Strip, Palestine

Traditional medicinal plants are valuable sources of bioactive compounds, many acting synergistically and their therapeutic uses are increasingly recognized. In this study, we examined the antimicrobial activity, antioxidant potential, and phytochemical constituents of four traditional medicinal plants (<i>Verbascum sinuatum</i>, <i>Amaranthus spinosus</i>, <i>Carduus getulus</i>, and <i>Heterotheca subaxillaris</i>) from the Gaza Strip in Palestine. Hexane extracts of each species were used for phytochemical characterization using Gas Chromatography - Mass Spectrometry (GC-MS). The total phenolic and flavonoid contents (TPC and TFC) were measured, followed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to examine the antioxidant activity. The antibacterial activity was assessed using the disc diffusion method. GC-MS analysis revealed that each species contained distinct lipophilic compounds. The major classes of components identified in <i>V. sinuatum</i> included saturated fatty acid esters, phenolic antioxidants, and a putative alkaloid. <i>A. spinosus</i> contained oxygenated monoterpenes, fatty acid derivatives, and aromatic compounds. <i>C. getulus</i> was characterized by monoterpenes, diterpenes, fatty acid derivatives, and phenolic antioxidants. <i>H. subaxillaris</i> primarily yielded terpenoids, fatty acid esters, and phenolic compounds. Quantitative phytochemical profiling revealed that <i>H. subaxillaris</i> exhibited the highest TPC and TFC among the four species. Hexane extracts of <i>H. subaxillaris</i>, <i>A. spinosus</i>, <i>V. sinuatum</i>, and <i>C. getulus</i> demonstrated measurable antioxidant activity and inhibitory effect against <i>Staphylococcus aureus</i>, <i>Bacillus cereus</i>, <i>Escherichia coli</i>, and <i>Pseudomonas aeruginosa</i>. Among the extracts, <i>H. subaxillaris</i> exhibited the strongest antioxidant and antibacterial activities followed, by <i>V. sinuatum</i>, <i>C. getulus</i>, and <i>A. spinosus</i>. These findings highlight the importance of phytochemical profiling in the discovery of new potential bioactive compounds and support future endeavors to isolate valuable metabolites, investigate their biosynthetic processes, and any structure-activity relationships.