Metabolism and antifungal activity of safrole, dillapiole, and derivatives against botryodiplodia theobromae and colletotrichum acutatum / Metabolismo y actividad antifúngica de safrol, dilapiol, y derivados contra botryodiplodia theobromae y colletotrichum acutatum

The direct in vitro fungitoxicity and metabolism of safrole and dillapiole (isolated from Piper auritum and Piper holtonii, respectively) by Botryodiplodia theobromae and Colletotrichum acutatum were investigated. Higher values of mycelial growth inhibition for both fungi were obtained for dillapiole, as compared with safrole. B. theobromae was able to metabolize both compounds to their respective vicinal diols, reaching 65 percent relative abundance during the biotransformation of dillapiole; while C. acutatum only transformed safrole to various metabolites with relative abundances under 5 percent. According to the low antifungal activity of the major metabolic products (< 5 percent for vicinal diols), a detoxification process was implied. Studies on the influence of some substituents in the aromatic ring of safrole and dillapiole on the antifungal activity against B. theobromae were also carried out. As result, the safrole nitrated derivative, 6-nitrosafrole, showed a fungitoxicity level similar to that displayed by the commercial fungicide Carbendazim® under the conditions used. In light of this, safrole and dillapiole could be suggested as feasible structural templates for developing new antifungal agents.

Se investigó la fungitoxicidad directa in vitro y el metabolismo de safrol y dilapiol (obtenidos desde Piper auritum and Piper holtonii, respectivamente) por Botryodiplodia theobromae y Colletotrichum acutatum. Los valores mayores de inhibición del crecimiento micelial de ambos hongos se obtuvieron para dilapiol, en comparación con safrol. B. theobromae metabolizó ambos compuestos a sus respectivos dioles vecinales, alcanzando abundancias relativas del 65 por ciento durante la biotransformación del dilapiol; mientras que C. acutatum solo transformó safrol en varios metabolitos con abundancias relativas menores al 5 por ciento. De acuerdo con la baja actividad antifúngica de los productos metabólicos mayoritarios (< 5 por ciento para los dioles vecinales), se sugiere un proceso de desintoxicación. Adicionalmente, se evaluó la influencia de algunos sustituyentes en el anillo aromático de safrol y dilapiol sobre la actividad antifúngica contra B. theobromae. Como resultado, el derivado nitrado del safrol, el 6–nitro safrol, presentó un nivel de fungitoxicidad similar al exhibido por el fungicida comercial Carbendazim® bajo las condiciones usadas. A la luz de lo anterior, safrol y dilapiol podrían ser sugeridos como plantillas estructurales adecuadas para el desarrollo de nuevos agentes antifúngicos.

Quaternary ammonium salt derivatives of allylphenols with peripheral analgesic effect

Ammonium salt derivatives of natural allylphenols were synthesized with the purpose of obtaining potential peripheral analgesics. These drugs, by virtue of their physicochemical properties, would not be able to cross the blood brain barrier. Their inability to enter into the central nervous system (CNS) should prevent several adverse effects observed with classical opiate analgesics (Ferreira et al., 1984). Eugenol (1) O-methyleugenol (5) and safrole (9) were submitted to nitration, reduction and permethylation, leading to the ammonium salts 4, 8 and 12. Another strategy applied to eugenol (1), consisting in its conversion to a glycidic ether (13), opening the epoxide ring with secondary amines and methylation, led to the ammonium salts 16 and 17. All these ammonium salts showed significant peripheral analgesic action, in modified version of the Randall-Sellito test (Ferreira et al. 1978), at non-lethal doses. The ammonium salt 8 showed an activity comparable to that of methylnalorphinium, the prototype of an ideal peripheral analgesic (Ferreira et al., 1984).