Interaction of asterriquinone with deoxyribonucleic acid in vitro

The interaction of asterriquinone (ARQ), a novel antitumor agent isolated from Aspergillus fungi, with deoxyribonucleic acid (DNA), has been studied. The binding of ARQ in vitro with DNA (calf thymus) was ascertained by its behavior in gel filtration using a Sephadex G-25 column at pH 5.4. Some ARQ analogs having no, or less, antitumor activity did not exhibit any evidence of interaction with DNA under the same condition. From the results obtained in this work, the pKa value of ARQs seemed to be critical between 6 and 7 for their binding to DNA and for exhibition of antitumor activity. Also, ARQ showed serious membrane deformations and an inhibitory effect on the membranous adenosine triphosphatase of Ehrlich carcinoma cells.