Electrochemical studies of the interaction of the anticancer herbal drug emodin with DNA

The interaction between anticancer herbal drug emodin and DNA was studied with differential pulse voltammetry (DPV) and cyclic voltammetry (CV) at the bare or DNA modified GCE and ultraviolet–visible (UV) spectra. The DPV of emodin showed that peak potentials shifted to more positive value and peak currents decreased with the addition of DNA. UV spectra exhibited that the absorption of emodin at about 440 nm decreased with red shift. The results showed that the herbal drug emodin interacted with DNA by intercalating into the double helix of DNA. Under our experiment conditions, the decrease of peak current was proportional to DNA concentration, which can be applied to determining DNA concentration. The combining constant (β) and combing number (m) of DNA–mEM were determined too.