Résumé
Lapachol was chemically modified to obtain its thiosemicarbazone and semicarbazone derivatives. These compounds were tested for antimicrobial activity against several bacteria and fungi by the broth microdilution method. The thiosemicarbazone and semicarbazone derivatives of lapachol exhibited antimicrobial activity against the bacteria Enterococcus faecalis and Staphylococcus aureus with minimal inhibitory concentrations (MICs) of 0.05 and 0.10 µmol/mL, respectively. The thiosemicarbazone and semicarbazone derivatives were also active against the pathogenic yeast Cryptococcus gattii (MICs of 0.10 and 0.20 µmol/mL, respectively). In addition, the lapachol thiosemicarbazone derivative was active against 11 clinical isolates of Paracoccidioides brasiliensis, with MICs ranging from 0.01-0.10 µmol/mL. The lapachol-derived thiosemicarbazone was not cytotoxic to normal cells at the concentrations that were active against fungi and bacteria. We synthesised, for the first time, thiosemicarbazone and semicarbazone derivatives of lapachol. The MICs for the lapachol-derived thiosemicarbazone against S. aureus, E. faecalis, C. gattii and several isolates of P. brasiliensis indicated that this compound has the potential to be developed into novel drugs to treat infections caused these microbes.
Sujets)
Antibactériens/pharmacologie , Antifongiques/pharmacologie , Naphtoquinones/pharmacologie , Semicarbazones/pharmacologie , Thiosemicarbazones/pharmacologie , Cryptococcus gattii/effets des médicaments et des substances chimiques , Enterococcus faecalis/effets des médicaments et des substances chimiques , Tests de sensibilité microbienne , Paracoccidioides/effets des médicaments et des substances chimiques , Staphylococcus aureus/effets des médicaments et des substances chimiquesRésumé
Este trabalho descreve a síntese e avaliaçäo estrutural de nove tiossemicarbazonas, obtidas pela condensaçäo de ariltioacetaldeídos e artiopropanonas substituídas com cloridrato de tiossemicarbazida. Estes novos compostos foram testados in vitro pelo fitoteste Lepidium sativum. Todos eles apresentaram atividade inibidora do crescimento celular (pI50) superior àquela de 5-fluoruacila, composto anticancerígeno, utilizado como referência.
Sujets)
Animaux , Antinéoplasiques/synthèse chimique , Inhibiteurs de croissance , Techniques in vitro , Thiosemicarbazones/synthèse chimique , Aldéhydes/pharmacologie , Aldéhydes/synthèse chimique , Spectroscopie par résonance magnétique , Semicarbazones/synthèse chimique , Semicarbazones/pharmacologie , Spectrophotométrie IR , Relation structure-activité , Thiosemicarbazones/composition chimique , Thiosemicarbazones/pharmacologieRésumé
O estudo da atividade antimicrobiana de nove semicarbazonas heterociclicas foi efetuado atraves de tres metodos, ineditos para estes compostos nas condicoes em que foram efetuados. No metodo da diluicao seriada em meio liquido utilizaram-se Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans e Aspergillus niger como microorganismos testes, ao passo que no metodo da difusao em meio solido utilizaram-se apenas Staphylococcus aureus, Escherichia coli e Candida albicans. Verificou-se que a atividade dos compostos foi muito baixa quando comparada com a 5-nitro-2-furanocarboxaldeidos semicarbazona, de atividade anteriormente comprovada. Pelo metodo da bioautografia verificou-se que das nove semicarbazonas ensaiadas, seis inibiram o crescimento do Cladosporium sphaerospermum