Synthesis and DNA-binding affinities of monomodified berberines

Abstract Four new monomodified berberines have been synthesized in moderate to good yields starting from berberine and fully characterized by HRMS and 1 H NMR. Spectrometric titration and ethidium bromide displacement experiments indicate that these berberine derivatives, especially the one having primary amino group, strongly bind with calf-thymus DNA, presumably via an intercalation mechanism.