Synthesis of linear Geranylphenols and their effect on mycelial growth of plant pathogen Botrytis cinerea.
Natural geranyl compounds are known to exhibit important biological activities. In this work a series of geranylphenols were synthesized to evaluate their effect on the mycelial growth of Botrytis cinerea. Geranyl derivatives were synthesized by direct geranylation reactions between the corresponding phenol derivatives and geraniol, using BF3.OEt2 as catalyst and AgNO3 as secondary catalyst. Previously reported molecules [geranylhydroquinone (2), geranylhydroquinone diacetate (6) and geranylphloroglucinol (9)], and new substances [(E)-4-(3,7-dimethylocta-2,6-dienyl)benzene-1,2,3-triol (geranyl-pyrogallol, 7), (E)-4-(3,7-dimethylocta-2,6-dienyl)benzene-1,2,3-triyl triacetate (8), (E)-2-(3,7-dimethylocta-2,6-dienyl)benzene-1,3,5-triyl triacetate geranylphloroglucinol triacetate (10), 2,4-bis((E)-3,7-dimethylocta-2,6-dienyl)benzene-1,3,5-triyl triacetate (11), 2,6-bis((E)-3,7-dimethylocta-2,6-dienyl)-3,5-dihydroxyphenyl acetate (12)], were obtained. All compounds were characterized by IR, HRMS and NMR spectroscopic data. The inhibitory effect of the synthesized compounds on the mycelial growth of Botrytis cinerea was tested in vitro. Excepting compound 11, all substances constrained the mycelial growth of Botrytis cinerea. The antifungal activity depends on the chemical structure of geranylphenol derivatives. Compounds 2 and 9 were the more effective substances showing inhibition degrees higher than those obtained with the commercial fungicide Captan, even at lower concentrations. Monosubstitution on the aromatic nucleus by a geranyl chain seems to be more effective for the inhibition of mycelial growth than a double substitution. These results suggest that the new derivatives of geranylphenols have the ability to block the mycelial development of the plant pathogen B. cinerea and that this capacity depends strongly on the structural features and lipophilicity of the compounds.
Departamento de Química, Universidad Técnica Federico Santa María, Av. España No. 1680, Valparaíso 2340000, Chile. luis.espinozac@usm.cl.
Luis
L
Espinoza
Departamento de Química, Universidad Técnica Federico Santa María, Av. España No. 1680, Valparaíso 2340000, Chile. lautaro.taborga@usm.cl.
Lautaro
L
Taborga
Departamento de Química, Universidad Técnica Federico Santa María, Av. España No. 1680, Valparaíso 2340000, Chile. katy.diaz@usm.cl.
Katy
K
Díaz
Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Quillota 980, Viña del Mar 2520000, Chile. aolea@unab.cl.
Andrés F
AF
Olea
Dirección de Investigación, Universidad de Valparaíso, Blanco 951, Valparaíso 2340000, Chile. hugo.pena@uv.cl.
Hugo
H
Peña-Cortés
D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D020171:Botrytis / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity; D005659:Fungicides, Industrial / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D025282:Mycelium / Q000187:drug effects* / Q000254:growth & development; D010636:Phenols / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D010944:Plants / Q000382:microbiology*; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D013729:Terpenes / Q000737:chemistry / Q000494:pharmacology
D000935:Antifungal Agents; D005659:Fungicides, Industrial; D010636:Phenols; D013729:Terpenes; C026301:geranylhydroquinone