Synthesis of neamine–carboline conjugates for RNA binding and their antibacterial activities

Three types of neamine-β-carboline conjugates were synthesized in good yields by the coupling of neamine and β-carboline-3-carboxylic acids using aliphatic diamine as a linker. The binding properties of these conjugates to 16S rRNA and 18S rRNA were evaluated by surface plasmon resonance (SPR), showing that some conjugates had stronger binding affinities than neamine. In vitro antimicrobial activities were also evaluated and the results showed that some synthetic compounds exhibited better antibacterial activities than neamine. The preliminary structure–activity relationship was discussed. The present experimental data demonstrated that synthetic neamine–carboline conjugates might hold the potential as new antibiotics.