Phytotoxicity of Anethum graveolens, Origanum majorana, Pelargonium graveolens, Satureja bachtiarica, Trachyspermum ammi, Zataria multiflora, and Ziziphora tenuior essential oils nanoemulsions as biological alternatives for weed control and design bioherbicide: in planta and in silico study

The overreliance on chemical herbicides poses risks to non-target species and ecosystems, highlighting the need for experimental and computational studies of natural alternatives. This study evaluates the phytotoxicity (germination and greenhouse) of essential oil-based nanoemulsions (EONE) from Anethum graveolens, Origanum majorana, Pelargonium graveolens, Satureja bachtiarica, Trachyspermum ammi, Zataria multiflora, and Ziziphora tenuior on Amaranthus retroflexus, Zea mays, and Glycine max. Notably, bioassay results were deepened by computational analysis to aid biological herbicide development and design. All applied EONE concentrations inhibited the weed germination, but some indicated selective herbicidal properties at post-emergence tests. For instance, Z. multiflora EONE selectively controlled redroot pigweed in soybeans, and P. graveolens EONE inhibited redroot pigweed without affecting corn in both pre-and post-emergence tests. Among herbicide protein targets, the D1 protein of photosystem II was detected through molecular docking as the target of phytotoxic terpenoids. Indeed, the components of phytotoxic essential oils, such as carvacrol, citronellol, and pulegone, had adequate potential to bind to the QB site with adequate type and energy, even compared to chemical inhibitors like Terbutryn. Conversely, the compounds of essential oils like O. majorana, which demonstrated weak phytotoxicity in the bioassay, had the inappropriate potential to bind this target site. Thus, in silico evaluations validated the findings from in planta experiments. Eventually, a library of 1911 essential oil components was screened using structure-based pharmacophore modeling, molecular docking, herbicide-likeness, quantum mechanical descriptors, and DFT analysis. This process identified benzyl salicylate as a novel and potent QB inhibitor, promising for future natural herbicide development.