New camphor hybrids: lipophilic enhancement improves antimicrobial efficacy against drug-resistant pathogenic microbes and intestinal worms

AbstractUsing the Blanc reaction, new derivatives of camphor (1a–g) and camphor sulfonic acid (2a–g) were synthesized. Chemical structures of the new derivatives were supported by IR,1H-NMR,13C-NMR, and LC-MS/MS (ESI) spectrometric analyses. The new compounds (1a–g/2a–g) and the parent compounds (a–g) were tested for their antimicrobial efficacy against the following drug-resistant pathogens: methicillin-resistantStaphylococcus aureus (MRSA), multi-drug resistantKlebsiella pneumonia (MDR-Kb),Escherichia coli (FDA control),Acinetobacter baumannii, Pseudomonas aeruginosa, Candida albicans (CLSI: Clinical and Laboratory Standards Institute strain) andCryptococcus neoformans var. grubii. The linking of camphor to quinoxalin-2,3(1H, 4H)-dione (1a) enhances the antibacterial efficacy approximately 8-folds (MIC: 24  µM) against MRSA. Camphor linking with isatin (1g) increased efficacy againstAcinetobacter baumannii by 8-fold (MIC: 26  µM) and by 4-fold (MIC: 51 µM) against MRSA, MDR-Kb,E. coli, P. auruginosa andC. albicans. Among the series, derivatives of benzoin (1e) and salicylic acid (1f) exhibited greater efficacy against drug-resistant Candida albicans, MDR-Kb andAcinetobacter baumannii, whereas 6, 7-biphenylquinoxalin 2-sulfonamide/sulphonyl chloride (1b/1d) selectively inhibited the growth of Gram-negative bacteria. None of these compounds were active againstCryptococcus neoformans var. grubii. Furthermore, these new derivatives were tested for anthelminti...
Source: Medicinal Chemistry Research - Category: Chemistry Source Type: research