spectroscopic studies on the interaction of anti cancer rosemary with ctdna

background some herbal anticancer agents have direct interactions with dna. objectives the present study aimed to investigate the interaction of ctdna with rosemary flowers. materials and methods we used uv-vis, fluorescence and circular dichroism (cd) spectroscopic techniques. results the absorption of dna at 260 nm increased on addition of rosemary. herb extract quench the fluorescence of etbr bound to ctdna. the stern-volmer constant (k) value for rosemary extract is 0.39 (mg/ml)-1. finally, the cd spectra indicate that rosemary induces some conformational changes in ctdna structure such as b to c-form transition. conclusions our results illustrate that rosemary extracts interact with ctdna through minor groove binding. this is one of the molecular mechanisms underlying anticancer effects of rosemary.