RESUMO
The increase in antibiotic resistance due to multiple factors has encouraged the search for new compounds which are active against multidrug-resistant pathogens. In this context, chalcones, dihydrochalcones, hydrazones and oxadiazoles were tested against Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus (MRSA) isolates, which were obtained from clinical laboratories and were characterized as MRSA using traditional and molecular methods. Among 65 tested compounds, two chalcones, one dihydrochalcone and two hydrazones were active against MRSA. Based on the minimal inhibitory concentration and cytotoxicity, hydrazones provided a better selectivity index than chalcones. Active hydrazones are promising antibiotic-like substances and they should be the subject of further microbiological studies.
Assuntos
Antibacterianos/farmacologia , Chalconas/farmacologia , Hidrazonas/farmacologia , Staphylococcus aureus Resistente à Meticilina/metabolismo , Meticilina/farmacologia , Oxidiazóis/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/metabolismo , Animais , Chalconas/química , Chlorocebus aethiops , Humanos , Hidrazonas/química , Testes de Sensibilidade Microbiana , Modelos Químicos , Infecções Estafilocócicas/microbiologia , Células VeroRESUMO
In order to obtain new compounds with antibacterial activity, the derivatives 2,4-dihydroxy-6-methylbenzoic acid (orsellinic acid) and 2,4-dihydroxy-6-methylbenzoates (orsellinates) were obtained through alcoholyses of lecanoric acid. All these substances were tested against Gram-positive and Gram-negative bacteria by a microdilution method. Staphylococcus aureus, Xanthomonas campestris var. vesicatoria and Ralstonia solanacearum were most sensitive to n-propyl 2,4-dihydroxy-6-methylbenzoate, n-pentyl 2,4-dihydroxy-6-methylbenzoate and n-hexyl 2,4-dihydroxy-6-methylbenzoate with MIC (Minimal Inhibitory Concentration) values ranging from 62.5 to 7.8 µg×mL¹. These results showed that homologation in carbon chain may lead to compounds with more pronunced activities.
Para obter novos compostos com atividade antibacteriana, foram preparados os derivados 2,4-diidróxi-6-metilbenzoatos (orselinatos) e o ácido 2,4-diidróxi-6-metilbenzóico (ácido orselínico) através de reações de alcoólise do ácido lecanórico. Todas as substâncias foram testadas contra bactérias Gram-positivas e Gram-negativas pelo método da microdiluição. Staphylococcus aureus, Xanthomonas campestris var. vesicatoria and Ralstonia solanacearum foram mais sensíveis ao 2,4-diidróxi-6-metilbenzoato de n-propila, 2,4-diidróxi-6-metilbenzoato de n-pentila e 2,4-diidróxi-6-metilbenzoato de n-hexila com valores de CIM (Concentração Inibitória Mínima) variando de 62,5 a 7,8 µg.mL¹. Esses resultados mostraram que a homologação da cadeia carbônica pode conduzir a compostos mais ativos.