title: Amino-substituted para-Benzoquinones as Potential Herbicides.
abstract: Although quinones present a large array of biological activities, a few studies on the herbicidal potential of 2,5-bis(alkyl/arylamino)-1,4-benzoquinones have been reported to date. In this work, starting from benzoquinone, 13 2,5-bis(alkyl/arylamino)-1,4-benzoquinones were prepared in 46 - 93% yield. The products were fully characterized by spectroscopic analyses and their phytotoxicity against Cucumis sativus and Sorghum bicolor seedlings was investigated. At 100 ppm, compounds caused 10 - 88% growth inhibition of the dicotyledonous species, whereas the monocotyledon was less affected. Most compounds exerted little inhibitory effect on a cyanobacterial model strain. However, at 100 μm, compounds 8 - 10 caused about 50% inhibition of algal growth, and compounds 1 and 2 reduced cell viability in the 1 - 10 μm range. The ability of benzoquinone derivatives to interfere with the light-driven ferricyanide reduction by isolated spinach chloroplasts was evaluated. Some substances showed a moderate effect as uncouplers, but no relationship was found between this property and their biological activity, indicating that the herbicidal effect is not associated with the inhibition of the photosynthetic electron transport chain. Phytotoxic compounds were not toxic to insects, strengthening the possibility that they may serve as lead for the development of eco-friendly herbicides.
authors.affiliation: Department of Chemistry, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627, Campus Pampulha, CEP 31270-901, Belo Horizonte, MG, Brazil.|Department of Chemistry, Federal University of Viçosa, Av. P. H. Rofls, s/n, Viçosa, MG, 36570-000, Brazil.
authors.forename: Amalyn
authors.initials: A
authors.lastname: Nain-Perez
authors.affiliation: Department of Chemistry, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627, Campus Pampulha, CEP 31270-901, Belo Horizonte, MG, Brazil. lcab@ufmg.br.|Department of Chemistry, Federal University of Viçosa, Av. P. H. Rofls, s/n, Viçosa, MG, 36570-000, Brazil. lcab@ufmg.br.
authors.forename: Luiz C A
authors.initials: LC
authors.lastname: Barbosa
authors.affiliation: Department of Entomology, Federal University of Viçosa, Av. P. H. Rofls, s/n, Viçosa, MG, 36570-000, Brazil.
authors.forename: Marcelo C
authors.initials: MC
authors.lastname: Picanço
authors.affiliation: Department of Life Science and Biotechnology, University of Ferrara, via L. Borsari 46, IT-44121, Ferrara.
authors.forename: Samuele
authors.initials: S
authors.lastname: Giberti
authors.affiliation: Department of Life Science and Biotechnology, University of Ferrara, via L. Borsari 46, IT-44121, Ferrara. flg@unife.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Forlani
mesh_terms: D000588:Amines / Q000737:chemistry*; D000818:Animals; D016227:Benzoquinones / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D018553:Cucumis sativus / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D006540:Herbicides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D007313:Insecta / Q000187:drug effects; D015394:Molecular Structure; D045868:Sorghum / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000588:Amines; D016227:Benzoquinones; D006540:Herbicides; C004532:quinone
keywords: 2,5-Bis(alky/arylamino)-1,4-benzoquinones; Algicidal activity; Herbicidal activity; Insecticidal activity; Photosynthetic inhibitors