Characterization of the Phytotoxic Potential of Seven Copaifera spp. Essential Oils: Analyzing Active Compounds through Gas Chromatography–Mass Spectrometry Molecular Networking

Authors: RIBEIRO, VICTOR - Orise Fellow; Bajsa-Hirschel, Joanna; BASTOS, JAIRO - Universidade De Sao Paulo; Reichley, Amber; DUKE, STEPHEN - University Of Mississippi; Meepagala, Kumudini

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2024
Publication Date: 8/6/2024
Citation: Ribeiro, V.P., Bajsa Hirschel, J.N., Bastos, J., Reichley, A.C., Duke, S.O., Meepagala, K.M. 2024. Characterization of the Phytotoxic Potential of Seven Copaifera spp. Essential Oils: Analyzing Active Compounds through Gas Chromatography–Mass Spectrometry Molecular Networking. Journal of Agricultural and Food Chemistry. 72:18528-18536. https://doi.org/10.1021/acs.jafc.4c04586.
DOI: https://doi.org/10.1021/acs.jafc.4c04586

Interpretive Summary: In recent years, there has been a growing interest in the use of natural compounds for weed management in agriculture. This study is aimed to assess the herbicidal constituents of oils obtained from oil resins of seven Copaifera species (known as copaiba oils). Copaiba oils were separated from the resins and analyzed. The seed germination bioassay of the oils against lettuce and grass seeds revealed strong seed germination prevention by all copaiba oils tested with some oils completely preventing seed germination. Further analyses analysis of oils showed variations in composition among Copaifera species, with some common compounds identified across multiple species. Caryophyllene oxide and junenol were associated with the observed seed germination effects. Chromatography was used to isolate the major compounds of the oils. Isolated compounds exhibited varying levels of seed germination compared to the oils, suggesting the importance of interactions of other minor constituents among oil components. These findings highlight the potential of Copaiba oils as natural herbicidal agents and underscore the importance of considering species-specific responses in weed management. Copaiba oils and their isolated compounds could contribute to the development of sustainable weed control methods in agriculture.

Technical Abstract: In recent years, there has been a growing interest in the phytotoxic properties of natural compounds for weed management in agriculture. This study is aimed to assess the phytotoxic constituents of oils obtained from oilresins of seven Copaifera species (known as copaiba oils). Copaiba oils were separated from the resins by hydro-distillation and, the distillates were analyzed using gas chromatography-mass spectrometry (GC-MS) to characterize their chemical compositions. Multivariate analyses and molecular networking of GC-MS data were conducted to discern patterns in the chemical composition and phytotoxic activity of the oils, aiming to identify key compounds associated with phytotoxic activity. Seed germination bioassay revealed strong or complete germination inhibition against the monocot, Agrostis stolonifera but not the dicot Lactuca sativa. GC-MS analysis showed variations in composition among Copaifera species, with some common compounds identified across multiple species. Caryophyllene oxide and junenol were associated with the observed phytotoxic effects. Automated flash chromatography was used to isolate the major compounds of the oils. Isolated compounds exhibited differing levels of phytotoxicity compared to the oils, suggesting the importance of interactions or synergism among oil components. These findings highlight the potential of copaiba oils as natural herbicidal agents and underscore the importance of considering species-specific responses in weed management strategies. Copaiba oils and their isolated compounds could contribute to the development of sustainable weed control methods in agriculture.