Chemical Profiling and Herbicidal Potential of <i>Amaranthus viridis</i> Essential Oil: Experimental and In Silico Insights

Essential oils (EOs) might offer a fresh supply of phytotoxic ingredients with potentially unique action modes. The current study represented the first work describing Amaranthus viridis EO chemical profiling and its bioherbicidal functions toward Dactyloctenium aegyptium and Bidens pilosa weeds, integrating action mechanisms through molecular docking on glutamine synthetase (GS) and acetohydroxyacid synthase (AHAS). The oil gas chromatography-mass spectrometry analysis revealed the identification of 50 components, mainly terpenes (94.79%) plus minor non-terpenes. The main compounds of EO were phytol (22.41%), trans-chrysanthenyl acetate (17.73%), cedr-8(15)-en-9-ol (11.74%), and torreyol (8.75%). The EO had strong effects on the germination and growth of D. aegyptium, with IC₅₀ values of 36.05 mg/L for germination, 23.39 mg/L for seedling roots, and 26.06 mg/L for seedling shoots. Also, EO attained IC₅₀ values of 43.35, 15.62, and 22.18 mg/L for the B. pilosa germination, seedling roots, and seedling shoots, respectively. The docking data showed that phytol demonstrated the strongest binding affinity at GS and AHAS with ΔG^a of -5.65 and -8.06 kcal/mol, respectively. Overall outcomes revealed the possibility of using A. viridis EO as a bioherbicide. Nevertheless, further research is strongly recommended to explore the bioherbicidal potential of the primary components-both individually and in combination-as well as to unravel their mechanisms of action and assess their safety in targeting weeds.