Abstract :

Capsaicin, the primary pungent compound in chili peppers (Capsicum species), exhibits a wide range of pharmacological and biological activities. Investigating its interaction with proteins is crucial for understanding its behaviour in biological systems and potential physiological effects. This study explores the binding of capsaicin with two model proteins, hemoglobin (Hb) and bovine serum albumin (BSA), using circular dichroism (CD) spectroscopy to evaluate structural changes induced by ligand interaction. Far-UV CD spectra of Hb and BSA reveals characteristic negative bands around 208 nm and 222 nm, consistent with their predominantly α-helical secondary structures. Upon titration with capsaicin, significant changes in the intensity of these bands were observed, indicating partial alterations in α-helical content and conformational adjustments in both proteins. These structural modifications suggest that capsaicin binds to Hb and BSA, likely through hydrophobic interactions and potential hydrogen bonding with specific amino acid residues. Comparative analysis showed differences in the extent of conformational change between Hb and BSA, reflecting variations in their binding affinity and interaction modes with capsaicin. The results highlight the impact of capsaicin on protein stability and secondary structure and demonstrate the utility of CD spectroscopy as an effective tool for probing protein–ligand interactions. This study provides valuable insights into the molecular mechanisms of capsaicin–protein binding, which may inform its physiological and therapeutic relevance.

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Keywords :

Capsaicin, Circular dichroism, metalloprotein., Serum albumin

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