Evaluation of herbicidal and fungicidal activities of six natural components and their phenoxyacetic acids derivatives and assessment of human health risk posed by oral exposure to them

ABSTRACT

In the present study, we isolated linalool, geraniol, carvacrol, thymol, menthol and eugenol; synthesised their phenoxyacetic acid derivatives; and assessed their phytotoxic and genotoxic potentials against weeds and agricultural crops. Moreover, the fungicidal activity of both categories of compounds against 12 fungi was examined. Finally, using probabilistic assessment based on Risk Quotient (RQ) by the Monte Carlo simulation (MCS) method, we examined human health risks via oral exposure to these compounds. Toxic potencies to plants demonstrated that all parameters and related indices including germination percentage, mean germination time, germination rate, root length, shoot length, seedling length and vigour index dose-dependently decreased in both weeds and agricultural crops. Based on the comet assay, DNA damage was observed in the root meristems of the plants. Consequently, a significant decrease was observed in head DNA, whereas a significant increase in tail DNA was observed in response to treatments. Besides, the natural components and semisynthetic molecules showed a broad spectrum of fungicidal traits. However, eugenol and eugenoxyacetic acid inhibitory effects on the growth of the tested fungi were similar to that of benomyl. Our probabilistic health risk assessment indicated di minimis risk for natural components and their phenoxyacetic acid derivatives. Sensitivity analysis showed that concentrations of residues of the compounds had the most significant effect on risk. Current findings could offer a platform for developing sustainable approaches to reduce chemical residues and their consequent risks to the environment and human health.

KEYWORDS:

• Co-exposure
• cumulative risk assessment
• herbicide mixtures
• phytoconstituents

Acknowledgments

Seyedeh Faezeh Taghizadeh was partially supported by a grant from Ferdowsi University of Mashhad (No. FUM-40949).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Author Taghizadeh, a Postdoctoral Fellow at Ferdowsi Uninersity of Mashhad, Mashhad, Iran, conducted laboratory analyses, wrote the manuscript, did statistical analyses, and the corresponding all authors. Author Azizi, a full professor of Department of Horticultural Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran, supervised the work, read and approved the final version of the manuscript. Author Rezaee, an assistant professor at International UNESCO Center for Health-Related Basic Sciences and Human Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran, critically reviewed analyses, and revised the manuscript. Author Asili, a full professor of Department of Pharmacognosy, Faculty of Pharmacy, Mashhad University of Medical sciences, Mashhad, Iran, designed the project. Author Karimi, a full professor of Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran designed and supervised the work and participated in calculations. Author Giesy, a full professor of Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, revised the manuscript. Author Farhadi Herbal and Traditional Medicines Research center, Kerman University of Medical Sciences, Kerman, Iran conducted laboratory analyses. Authors Salavati Nik and Hassanpourfard and MSC students at Department of Horticultural Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran conducted laboratory analyses.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03067319.2022.2118595

Additional information

Funding

This work was supported by the College of Agriculture, Ferdowsi University of Mashhad [40949].