acronine and thioacridone

The well-reported, but moderate antitumor activity of the acronycine alkaloid led us to synthesize a novel series of thioacridone compounds related to acronycine, as potential anticancer agents. Compounds were designed either as DNA intercalating agents, or as DNA intercalating agents with covalent bond forming potential. Bathochromic shifts of the compounds upon complexation with salmon testis DNA suggested intercalation as the mode of DNA binding. The binding interaction of the compounds was found to be approximately 10(2) M(-1), with that of the most potent compound 1-(2-dimethylaminoethylamino)-9(10H)-thioacridone, 10(4) M(-1). In vitro cytotoxic activity (IC50) against HL-60 cells was found to range between 3.5 and 22 microg/mL. QSAR analyses yielded a multiple linear regression equation with an r2 of 0.847 for DNA binding and an r2 of 0.575 for cytotoxicity. The physicochemical parameters used in the QSAR analyses were logP, polar surface area, and calculated molar refractivity. Docking studies were also performed to compare the binding of the most potent and least potent compounds in the study in order to predict desirable chemical characteristics for further exploitation in drug design efforts. The thioacridone compounds in this series demonstrate cytotoxic activity in vitro that merit future in vivo evaluation.

Topics: Acridines; Acronine; Antineoplastic Agents, Phytogenic; DNA; HL-60 Cells; Humans; Magnetic Resonance Spectroscopy; Models, Molecular; Quantitative Structure-Activity Relationship

A series of thioacridone compounds that were previously shown to have DNA binding interaction, were screened for antimalarial activity. The new compounds were assessed for in vitro antimalarial activity against a chloroquine sensitive (D10) strain of the malaria parasite Plasmodium falciparum, using a lactate dehydrogenase (PfLDH) assay. In the series, the IC(50) values ranged from 0.4 to 27 microg/ml. 1-(2-Dimethylaminoethylamino)-9(10H)-thioacridone was found to be the most potent against P. falciparum (D10) with an IC(50) value of 0.4 microg/ml. This compound was also evaluated against a South African chloroquine resistant (RSA 11) P. falciparum strain and was found to have an IC(50) value of 1 microg/ml, compared with 0.16 microg/ml for chloroquine. Quantitative structure-activity relationships of this series were also investigated and a multiple linear regression r(2) of 0.58 was found for the best fit equation. The most potent compound, 1-(2-dimethylaminoethylamino)-9(10H)-thioacridone, was docked into the chloroquine binding site of PfLDH and it was found that the slightly lower activity of this compound, compared with chloroquine, is likely due to steric interference within a restricted binding pocket.

Topics: Acridines; Acronine; Alkaloids; Animals; Antimalarials; Plasmodium falciparum; Quantitative Structure-Activity Relationship