Antibacterial activity of adamantyl substituted cyclohexane diamine derivatives against methicillin resistant Staphylococcus aureus and Mycobacterium tuberculosis

A series of forty two adamantyl based cyclohexane diamine derivatives were synthesized and the antibacterial activities of these compounds were assessed against 29 strains of methicillin resistant Staphylococcus aureus (MRSA) and a virulent strain of Mycobacterium tuberculosis. The compounds showed potent to moderate activity against MRSA while moderate to weak activity against the virulent strain of M. tuberculosis. The compound 8e showed the most potent activity against MRSA having minimum inhibitory concentration (MIC) values in the range of 8-64 μg mL^-1 against 26 MRSA strains out of the 29 strains examined. It exhibited improved inhibitory activity compared to oxacillin. Compound 8i with an MIC value of 13.7 μM against M. tuberculosis, was bactericidal with rapid kill kinetics demonstrating a 4 log reduction in viability of M. tuberculosis within 7 days.