tiliroside and Necrosis

Two polyphenolics, kaempferol 3-O-beta-D-(6"-E-p-coumaroyl)-glucopyranoside (tiliroside) (1) and methyl brevifolincarboxylate (2) isolated from aerial parts of Potentilla argentea L. (Rosaceae) were evaluated for their cytotoxicities against human breast carcionoma cell line (MCF-7) and their DNA-binding ability. The DNA-binding ability of these compounds was studied by means of the human DNA topoisomerase I and II inhibition assay and ethidium displacement assay using calf thymus DNA, poly(dA-dT)2 and poly(dG-dC)2. Compound 2 was much more active and showed a higher level of cytotoxic potency than compound 1, with IC50 values of 1.11 +/- 2 microM and 21.60 +/- 2 microM, respectively. In DNA topoisomerase I and II inhibition in vitro assays both investigated compounds 1 and 2 were more effective against topoisomerase II than I. The results of DNA binding studies reveal that methyl brevifolincarboxylate had a greater DNA binding affinity that tiliroside, which correlates with its greater potency as a topoisomerase I/II inhibitor.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Benzopyrans; Camptothecin; Cell Line, Tumor; DNA; DNA, Neoplasm; Enzyme Inhibitors; Ethidium; Female; Flavonoids; Humans; Necrosis; Poly dA-dT; Poly G; Potentilla; Topoisomerase I Inhibitors; Topoisomerase II Inhibitors