Synthesis and DNA-binding affinities of monomodified berberines

Four new monomodified berberines have been synthesized in moderate to good yields starting from berberine and fully characterized by HRMS and H-1 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. (c) 2005 Elsevier Ltd. All rights reserved.