Spectral and computational features of the binding between riparins and human serum albumin

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2018-02, Vol.190, p.81-88
• Main Authors: Camargo, Cintia Ramos, Caruso, Ícaro Putinhon, Gutierrez, Stanley Juan Chavez, Fossey, Marcelo Andres, Filho, José Maria Barbosa, Cornélio, Marinônio Lopes
• Format: Article
• Language: English
• Subjects: Binding density function; Computational methods; Drug displacement; Fluorescence; Human serum albumin; Riparin
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2017.08.068

The green Brazilian bay leaf, a spice much prized in local cuisine (Aniba riparia, Lauraceae), contains chemical compounds presenting benzoyl-derivatives named riparins, which have anti-inflammatory, antimicrobial and anxiolytic properties. However, it is unclear what kind of interaction riparins perform with any molecular target. As a profitable target, human serum albumin (HSA) is one of the principal extracellular proteins, with an exceptional capacity to interact with several molecules, and it also plays a crucial role in the transport, distribution, and metabolism of a wide variety of endogenous and exogenous ligands. To outline the HSA–riparin interaction mechanism, spectroscopy and computational methods were synergistically applied. An evaluation through fluorescence spectroscopy showed that the emission, attributed to Trp 214, at 346 nm decreased with titrations of riparins. A static quenching mechanism was observed in the binding of riparins to HSA. Fluorescence experiments performed at 298, 308 and 318 K made it possible to conduct thermodynamic analysis indicating a spontaneous reaction in the complex formation (ΔG