Physiological and Oxidative Stress Responses of Lettuce to Cleomside A: A Thiohydroximate, as a New Allelochemical from Cleome arabica L

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-09, Vol.25 (19), p.4461
• Main Authors: Ladhari, Afef, Andolfi, Anna, DellaGreca, Marina
• Format: Article
• Language: English
• Subjects: Acetates - chemistry; Acetic acid; allelochemicals; Allelopathy; Antioxidants; Antioxidants - pharmacology; Bioactive compounds; Biological activity; Biomarkers - analysis; Carbon; Carbon-13 Magnetic Resonance Spectroscopy; Cleome; Cleome - chemistry; Cleome arabica; Cluster Analysis; Electrolyte leakage; Electrolytes - metabolism; Enzymes; Ethyl acetate; Flavonoids; Herbicides; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Lactuca - drug effects; Lactuca - enzymology; Lactuca - physiology; Lettuce; Lipid peroxidation; Malondialdehyde; membrane integrity; Metabolites; Mitotic Index; Natural products; oxidative damage; Oxidative stress; Oxidative Stress - drug effects; Pheromones - pharmacology; Physiology; Phytotoxicity; Plant Roots - cytology; Plant Roots - drug effects; Principal Component Analysis; Proton Magnetic Resonance Spectroscopy; Reactive oxygen species; Secondary Metabolism; Secondary metabolites; Stress response; thiohydroximate; Toxicity Tests
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25194461

The inclination toward natural products have led the onset for the discovery of new bioactive metabolites that could be targeted for specific therapeutic or agronomic applications. This study aimed to isolate bioactive compounds from L., and subsequently determine the unexplored mechanism of action of the newly identified compounds on L. Chemical investigation of the ethyl acetate fraction of methanolic silique extract of afforded seven secondary metabolites belonging to different classes such as flavonoids, triterpene, and a new thiohydroximate derivative, named cleomside A. Among phytotoxic assays, the growth of lettuce was totally inhibited by cleomside A compared to the other identified compounds. This effect was associated with the increased levels of electrolyte leakage, malondialdehyde, and hydrogen peroxide indicating disruption of membrane integrity and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, and APX were also elevated, thereby demonstrating the enhanced generation of reactive oxygen species upon identified allelochemical exposure. Thus, the changes caused by cleomside A described herein can contribute to better understanding the allelochemical actions of thiohydroximate and the potential use of these substances in the production of natural herbicides compared to the other identified flavonoids and triterpene.