RT journal article T1 Bioprospection of Phytotoxic Plant-Derived Eudesmanolides and Guaianolides for the Control of Amaranthus viridis, Echinochloa crus-galli, and Lolium perenne Weeds A1 García Zorrilla, Jesús A1 Cárdenas, David M. A1 Rial Cumbrera, Carlos A1 González Molinillo, José María A1 Varela Montoya, Rosa María A1 Masi, Marco A1 Macías Domínguez, Francisco Antonio A2 Química Orgánica K1 phytotoxicity studies K1 weed control K1 herbicide development models K1 bioassays K1 sesquiterpene lactones K1 structure−activity relationships AB The phytotoxicities of a selection of eudesmanolides and guaianolides, including natural products and new derivatives obtained by semisynthesis from plant-isolated sesquiterpene lactones, were evaluated in bioassays against three weeds of concern in agriculture (Amaranthus viridis L., Echinochloa crus-galli L., and Lolium perenne L.). Both eudesmanolides and guaianolides were active against the root and shoot growth of all the species, with the eudesmanolides generally showing improved activities. The IC50 values obtained for the herbicide employed as positive control (on root and shoot growth, respectively, A. viridis: 27.8 and 85.7 μM; E. crus-galli: 167.5 and 288.2 μM; L. perenne: 99.1 and 571.4 μM) were improved in most of the cases. Structure–activity relationships were discussed, finding that hydroxylation of the A-ring and C-13 as well as the position, number, and orientation of the hydroxyl groups and the presence of an unsaturated carbonyl group can significantly influence the level of phytotoxicity. γ-Cyclocostunolide was the most active compound in the series, followed by others such as dehydrozaluzanin C and α-cyclocostunolide (outstanding their IC50 values on A. viridis)─natural products that can therefore be suggested as models for herbicide development if further research indicates effectiveness on a larger scale and environmental safety in ecotoxicological assessments. PB American Chemical Society SN 0021-8561 YR 2024 FD 2024-01-11 LK http://hdl.handle.net/10498/31418 UL http://hdl.handle.net/10498/31418 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 07-nov-2026