Studies on interaction of norbixin with DNA: Multispectroscopic and in silico analysis

• The interaction between food colorant norbixin with CTDNA.
• Partial intercalation and groove binding of norbixin with CTDNA.
• Lowest conformation energy of norbixin.

The interaction of food colorant norbixin with calf thymus DNA (CTDNA) was investigated through UV–Visible spectroscopy, Fourier Transform Infrared (FTIR), Circular Dichroism (CD), Nuclear Magnetic Resonance (NMR), DNA melting studies, electrophoretic analysis, histological staining technique and molecular docking studies. The results indicated that norbixin interacted with CTDNA by partial intercalation mode. The binding constant (K) of norbixin with CTDNA was calculated to be 5.08 × 105 Mol−1 L. FTIR and CD studies were coupled with 1H NMR spectra revealed that norbixin intercalates partially and binds to the groove’s, phosphate group, deoxyribose sugar of DNA and also induces conformational transition of B-form to A-form DNA. Agarose gel electrophoretic and histological staining technique results further prove that, norbixin specifically binds to the DNA in the cell. Moreover, molecular docking studies on the specific binding of norbixin with CTDNA have exhibited lowest conformation energy score of −3.2. Therefore, this food colorant has the ability to interact with DNA and it could emerge as a promising class of natural DNA targeted therapeutic.

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