Supplementary Material for: Interaction Studies of an Anticancer Alkaloid, (+)-(13aS)-Deoxytylophorinine, with Calf Thymus DNA and Four Repeated Double-Helical DNAs

<i>Background:</i> Phenanthroindolizidine alkaloids are a family of plant-derived compounds with significant antineoplastic activity. The specific biomolecular targets of these alkaloids have not yet been clearly identified. (+)-(13aS)-deoxytylophorinine is a new phenanthroindolizidine alkaloid originally extracted from the roots of <i>Tylophora atrofolliculat</i>a and <i>Tylophora ovata</i> in our institute. (+)-(13aS)-deoxytylophorinine exerts both in vitro and in vivoanticancer activities. <i>Methods:</i> The in vivo anticancer effects and toxicity of this compound were investigated in mice, and interactions between this compound and double-helical DNA sequences were studied in detail with circular dichroic spectroscopy and fluorescence spectroscopy. Viscosity measurements were applied to check the interactive mode between this compound and DNA. <i>Results:</i> Potent anticancer effects were observed in vivo. Also, concentration-dependent interactions were observed and this compound seemed to interact in a sequence-specific manner with AT-repeated sequences of double-helical DNA. Such interactions were proved to be intercalating by viscosity measurements. <i>Conclusions:</i> Anticancer alkaloid (+)-(13aS)-deoxytylophorinine can have sequence-specific interactions with DNA in an intercalating manner.