title: Cyclopent-4-ene-1,3-diones: a new class of herbicides acting as potent photosynthesis inhibitors.
abstract: In a recent paper, we reported the synthesis and photosynthesis-inhibitory activity of a series of analogues of rubrolides. From quantitative structure-activity relationship (QSAR) studies, we found that the most efficient compounds are those having higher ability to accept electrons. On the basis of those findings, we directed our effort to synthesize new analogues bearing a strong electron-withdrawing group (nitro) in the benzylidene ring and evaluate their effects on photosynthesis. However, the employed synthetic approach led to novel cyclopent-4-ene-1,3-diones as major products. Here, we report the synthesis and mechanism of action of such cyclopent-4-ene-1,3-diones as a new class of photosynthesis inhibitors. These compounds block the electron transport at the QB level by interacting at the D1 protein at the reducing side of Photosystem II and act as Hill reaction inhibitors, with higher activity than the corresponding rubrolides. To the best of our knowledge, this is the first report on the photosynthesis inhibitory activity of cyclopentenediones.
authors.affiliation: Department of Chemistry, Federal University of Viçosa , Avenida Peter Henry Rolfs, s/n, 36570-000 Viçosa, Minas Gerais, Brazil.
authors.forename: Jodieh O S
authors.initials: JO
authors.lastname: Varejão
authors.forename: Luiz C A
authors.initials: LC
authors.lastname: Barbosa
authors.forename: Eduardo V V
authors.initials: EV
authors.lastname: Varejão
authors.forename: Célia R A
authors.initials: CR
authors.lastname: Maltha
authors.forename: Beatriz
authors.initials: B
authors.lastname: King-Díaz
authors.forename: Blas
authors.initials: B
authors.lastname: Lotina-Hennsen
mesh_terms: D002736:Chloroplasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D006540:Herbicides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D010648:Phenylacetates / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects*; D045332:Photosystem II Protein Complex / Q000037:antagonists & inhibitors / Q000378:metabolism; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D018724:Spinacia oleracea / Q000187:drug effects* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D006540:Herbicides; D010648:Phenylacetates; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; C002864:cyclodrine