Investigating the Impact of Irrigation Water Quality on Secondary Metabolites and Chemical Profile of Mentha piperita Essential Oil: Analytical Profiling, Characterization, and Potential Pharmacological Applications

This study examines the impact of irrigation water quality on the synthesis of secondary metabolites and the chemical composition of Mentha piperita essential oil (MPEO). Three essential oils from Mentha piperita plants, irrigated with different water sources commonly used for mint irrigation in Morocco’s Oriental region, were analyzed. The water sources were characterized based on various parameters, such as nitrites, nitrates, orthophosphates, chemical oxygen demand (COD), biological oxygen demand (BOD5), pH, and electrical conductivity. The essential oils were extracted using hydrodistillation, and their chemical composition was determined using gas chromatography coupled with mass spectrometry (GC/MS), revealing notable variations among the compositions of the three essential oils. In this study, in silico tests using the Prediction of Activity Spectra for Substances (PASS) algorithm; the absorption, distribution, metabolism, and excretion (ADME) model; and Pro-Tox II were conducted to evaluate the drug-likeness, pharmacokinetic properties, expected safety profile upon ingestion, and potential pharmacological activity of the identified compounds in MPEO. The antioxidant activity of the MPEOs was assessed through a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and the total antioxidant activity (TAC) method. Additionally, the antimicrobial effectiveness of the essential oils was tested against four bacterial strains (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa) and four fungal strains (Candida glabrata, Rhodotorula glutinis, Penicillium digitatum, Aspergillus niger), demonstrating moderate to strong activities against the tested strains. This study concludes that regulating irrigation water quality can enhance the production of specific metabolites, making them potentially valuable as antioxidants and antimicrobial agents.