Phytotoxic Effects and Mechanism of Action of Essential Oils and Terpenoids

Abstract

Weeds are one of the major constraints in crop production affecting both yield and quality. The excessive and exclusive use of synthetic herbicides for their management is increasing the development of herbicide-resistant weeds and is provoking risks for the environment and human health. Therefore, the development of new herbicides with multitarget-site activity, new modes of action and low impact on the environment and health are badly needed. The study of plant–plant interactions through the release of secondary metabolites could be a starting point for the identification of new molecules with herbicidal activity. Essential oils (EOs) and their components, mainly terpenoids, as pure natural compounds or in mixtures, because of their structural diversity and strong phytotoxic activity, could be good candidates for the development of new bioherbicides or could serve as a basis for the development of new natural-like low impact synthetic herbicides. EOs and terpenoids have been largely studied for their phytotoxicity and several evidences on their modes of action have been highlighted in the last decades through the use of integrated approaches. The review is focused on the knowledge concerning the phytotoxicity of these molecules, their putative target, as well as their potential mode of action.

Secondary Metabolites and Eco-Friendly Techniques for Agricultural Weed/Pest Management

“…Similarly, Abd-ElGawad et al [ 12 ] bioassayed in vitro the EOs extracted from Argemone ochroleuca Sweet, mainly constituted by oxygenated terpenoids, on noxious weed Peganum harmala. Their results confirmed the hypothesis that oxygenated monoterpenes were more phytotoxic than non-oxygenated ones [ 13 ]. Finally, Synowiec and Krajewska [ 11 ] demonstrated that maltodextrin microencapsulated peppermint oil mixed with silty clay loam soil substrate strongly inhibited the growth of wild mustard, suggesting that the microencapsulation could be an excellent strategy to formulate new bio-herbicides.…”

Nematicidal and Molecular Docking Investigation of Essential Oils from Pogostemon cablin Ecotypes against Meloidogyne incognita

“…In this context, eco‐benign phytochemicals such as plant essential oils based strategies could be efficient to manage nematodes [6] . Volatile essential oils (EOs) are primarily comprising of aromatic terpenenes, alcohols, aldehydes, ketones, esters, and hydrocarbons [7] which have been investigated for potential nematicidal activity [8] . Volatile oils distilled from herbs have been documented for possessing significant nematicidal activity against M. incognita [9,10] .…”

Chemical Composition and Broad-Spectrum Insecticidal Activity of the Flower Essential Oil from an Ancient Sicilian Food Plant, Ridolfia segetum

“…It will also be necessary to determine whether the EO from R. segetum causes any phytotoxicity in the treated plants. High concentrations of EOs are known for their potential to exhibit herbicidal activity [81]. However, also it is known that although low doses of plant EOs may not show acute toxicity against S. littoralis larvae, they can cause chronic toxicity, as demonstrated, for example, for EOs extracted from Pimenta racemosa (Mill.)…”