Antimicrobial assesment of aroylhydrazone derivatives in vitro

Abstract Aroylhydrazones 1–13 were screened for antimicrobial and antibiofilm activities in vitro. N′ -(2-hydroxy-phenylmethylidene)-3-pyridinecarbohydrazide ( 2 ), N′ -(5-chloro-2-hydroxyphenyl-methylidene)-3-pyridinecarbohydrazide ( 10 ), N′ -(3,5-chloro-2-hydroxyphenylmethylidene)-3-pyridinecarbohydrazide ( 11 ), and N′ -(2-hydroxy-5-nitrophenylmethylidene)-3-pyridinecarbohydrazide ( 12 ) showed antibacterial activity against Escherichia coli , with MIC values (in µmol mL −1 ) of 0.18–0.23, 0.11–0.20, 0.16–0.17 and 0.35–0.37, resp. Compounds 11 and 12 , as well as N′ -(2-hydroxy-3-methoxyphenylmethylidene)-3-pyridinecarbohydrazide ( 6 ) and N′ -(2-hydroxy-5- methoxyphenylmethylidene)-3-pyridinecarbohydrazide ( 8 ) showed antibacterial activity against Staphylococcus aureus , with the lowest MIC values of 0.005–0.2, 0.05–0.12, 0.06–0.48 and 0.17–0.99 µmol mL −1 . N′ -(2-hydroxy-5-methoxyphenylmethylidene)-3-pyridinecarbohydrazide ( 7 ) showed antifungal activity against both fluconazole resistant and susceptible C. albicans strains with IC 90 range of 0.18–0.1 µmol mL −1 . Only compound 11 showed activity against C. albicans ATCC 10231 comparable to the activity of nystatin (the lowest MIC 4.0 ×10 −2 vs . 1.7 × 10 −2 µmol mL −1 ). Good activity regarding multi-resistant clinical strains was observed for compound 12 against MRSA strain ( MIC 0.02 µmol mL −1 ) and compounds 2 , 6 and 12 against ESBL+ E. coli MFBF 12794, with the lowest MIC for compound 12 ( IC 50 0.16 µmol mL −1 ). Anti-biofilm activity was found for compounds 2 ( MBFIC 0.015–0.02 µmol mL −1 against MRSA) and 12 ( MBFIC 0.013 µmol mL −1 against EBSL+ E. coli ). In the case of compound 2 against MRSA biofilm formation, MBFIC values were comparable to those of gentamicin sulphate, whereas in the case of compound 12 and EBSL+ E. coli even more favourable activity compared to gentamicin was observed.