Understanding the interaction of telmisartan and DNA: Mechanisms and prospects for therapy

Investigating DNA-drug interaction mechanisms plays a crucial role in designing therapeutic agents with high efficacy and low toxicity. This study investigates the interaction of telmisartan, a commonly prescribed anti-hypertensive drug, with calf thymus DNA (ct-DNA) by multiple spectroscopic and physicochemical procedures. Ultraviolet-Visible (UV-Vis) absorption studies revealed a significant increase in hyperchromicity with the addition of telmisartan, suggesting strong binding to DNA. Fluorescence quenching experiments further confirmed this interaction, yielding a Stern-Volmer quenching constant (Ksv) of 4.6 × 10³ M-¹. Displacement assay by utilizing acridine orange (AO) and ethidium bromide (EB) indicated that telmisartan largely binds to DNA via intercalation. The binding strength was quantified by Ksv, determined to be 2.8 × 10³ M-¹ for AO and 2.6 × 10³ M-¹ for EB. Alterations in the DNA’s helical structure upon binding with telmisartan was also demonstrated by circular dichroism (CD), and viscosity measurements demonstrated an increase in DNA length, further supporting intercalation. In addition, an increment of 5 °C was observed in melting temperature (Tm) of DNA by adding telmisartan, indicating enhanced DNA helical stability. In conclusion, the above findings provide valuable insights into the DNA-telmisartan interaction, contributing to the future design of more effective therapeutic agents.