Phytogrowth- and photosynthesis-inhibiting properties of nostoclide analogues.
Six nostoclide analogues were synthesised from 3-benzyl-2(5H)-furanone in one step, with yields ranging from 10 to 71%, and subjected to several biological assays. The two most active of these, 5d and 5e, were shown to be phytogrowth inhibitors of the radicle of Lolium multiflorum Lam, while enhancing the root growth of Physalis ixocarpa Brot. Both compounds inhibited electron flow (basal, phosphorylating and uncoupled) from water to methylviologen (MV); both acted as Hill reaction inhibitors, since the synthesis of ATP was prevented. The uncoupled electron transport from photosystem II (PSII) (water to 2,6-dichlorophenol-indophenol (DPIP)) and photosystem I (PSI) (2,6-dichlorophenol-indophenol reduced (DPIPred) to MV) was inhibited with 500 microM of 5d by 22 and 14% respectively. In addition, 400 microM of 5d inhibited PSI (from tetramethyl-p-benzohydroquinone (TMQH(2)) to MV) by 40%. Thus 5d inhibited electron transport at the b(6)f complex. Finally, 500 microM of 5e inhibited electron flow (basal and phosphorylating) by 25%, and 300 microM of 5e enhanced light-activated membrane-bound Mg(2+)-ATPase by 66%. Thus 5e behaved as a weak Hill reaction inhibitor and an uncoupler. In general, the phytotoxicity of the synthetic lactones was only weakly related to inhibition of photosynthesis.
Departamento de Química, Universidade Federal de Viçosa, 36571-000 Viçosa, MG, Brazil. lcab@ufv.br
Luiz Ca
LC
Barbosa
Antônio J
AJ
Demuner
Elson S
ES
de Alvarenga
Alberto
A
Oliveira
Beatriz
B
King-Diaz
Blas
B
Lotina-Hennsen
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D006540:Herbicides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008129:Lolium / Q000187:drug effects*; D015394:Molecular Structure; D010788:Photosynthesis / Q000187:drug effects*; D032321:Physalis / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D018724:Spinacia oleracea / Q000187:drug effects
D006540:Herbicides; C510490:nostoclide I; C510491:nostoclide II; D017301:Ca(2+) Mg(2+)-ATPase; D015107:4-Butyrolactone