Phenolic Profiles of Silybum marianum and Xanthium strumarium as Indicators of Environmental Pollution in Mosul City, Iraq

Water pollution represents a major environmental challenge in Iraq, especially in Mosul City, where industrial, residential, and commercial effluents are discharged into natural ecosystems. Plants exposed to such stresses often show altered phenolic metabolism, making phenolic compounds valuable biomarkers for monitoring ecological contamination. However, little is known about the variation of phenolic compounds in wild plants of Mosul under different pollution regimes. This study aimed to evaluate the impact of water pollution on phenolic compound concentrations in two wild species, Silybum marianum and Xanthium strumarium. Plant samples were collected during April 2025 from four ecologically distinct sites in Mosul: Ghanem Al-Sayyed Industrial Zone, Al-Muthanna residential area near a power plant, the Corniche commercial district, and forest of Mosul (control site). High-Performance Liquid Chromatography (HPLC) was employed to quantify key phenolic compounds. Results showed a marked reduction in phenolic content at polluted sites compared to the control. In S. marianum, cinnamaldehyde and cinnamic acid decreased to 4.630mg/ L in Corniche and 1.971mg/ L in Al-Muthanna. In X. strumarium, chlorogenic acid and vanillic acid declined to 2.841 and 7.779mg/ L, respectively, in Corniche area. These findings highlight the sensitivity of wild plants to pollution and demonstrate the potential of S. marianum and X. strumarium as effective bioindicators of water quality in urban ecosystems. Future research should integrate physical, chemical analysis of water to strengthen the link between pollution risk and plant biochemical reactions.