Synthesis of isatin thiosemicarbazones derivatives: In vitro anti-cancer, DNA binding and cleavage activities

•New derivatives of thiosemicarbazone Schiff base with isatin moiety were synthesized.•The interaction of these compounds with calf thymus CT-DNA exhibited high intrinsic binding constant.•The electrophoresis studies show the higher cleavage activity of L1–L3.•Compounds (L3, L6 and L2) exhibited good anticancer activity.

New derivatives of thiosemicarbazone Schiff base with isatin moiety were synthesized L1–L6. The structures of these compounds were characterized based on the spectroscopic techniques. Compound L6 was further characterized by XRD single crystal. The interaction of these compounds with calf thymus (CT-DNA) exhibited high intrinsic binding constant (kb = 5.03–33.00 × 105 M−1) for L1–L3 and L5 and (6.14–9.47 × 104 M−1) for L4 and L6 which reflect intercalative activity of these compounds toward CT-DNA. This result was also confirmed by the viscosity data. The electrophoresis studies reveal the higher cleavage activity of L1–L3 than L4–L6. The in vitro anti-proliferative activity of these compounds against human colon cancer cell line (HCT 116) revealed that the synthesized compounds (L3, L6 and L2) exhibited good anticancer potency.

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