[Inhibition of the reactions of DNA hydrolysis and RNA synthesis by the alkaloid sanguinarine].

The increase of the contour length of the low molecular linear duplex DNA in the complex with an alkaloid sanguinarine has been evidenced by the viscometric method. The enzymatic hydrolysis of modified DNA by pancreatic deoxyribonuclease I and RNA synthesis of DNA by rat liver nuclear RNA polymerase were studied. Sanguinarine has been shown to inhibit the first stages of DNA hydrolysis. This alkaloid is a weaker inhibitor than ethidium bromide, a more potent inhibitor than actinomycin D and exerts an inhibiting effect similar to that of distamycin A. Sanguinarine also decreases the rate of the labelled precursor incorporation into the acid-insoluble fractions by nuclear RNA polymerase from rat liver. A 50% inhibition by sanguinarine was observed at the same alkaloid concentration as that of ethidium bromide.