The affinity and mode of interaction of four novel organogermanium sesquioxides with calf thymus DNA（CT-DNA） and two synthetic oligonucleotides, d（AT）22d（AT）22 and d（GC）22d（GC）22, were investigated by a combination of absorption spectroscopy, DNA thermal denaturalization method, viscosity method, fluorometric technique, and competitive binding study with ethidium bromide（EB）. The results show that the organogermanium compounds can interact with DNA by intercalation, the binding ability of the compounds to CT-DNA and the synthetic oligonucleotides was found to be modest（in comparison to the proven intercalators）, With binding constants on the order of 10^3-10^5 L/mol, respectively. Generally, the binding of the organogermanium sesquioxides with naphthalene moiety to DNA is stronger than that of the compounds with anthraquinone moiety. And the compounds with anthraquinone moiety have preference for binding to AT-rich duplexes, whereas the compounds with naphthalene moiety have a little preference for binding to GC-rich duplexes. DNA may be the primary effect target.
