Abstract:

The effects of deionized water (dH2O), NaCl solution and phosphate buffer saline (PBS) on bovine serum
albumin (BSA)/anthocyanin (ACN) interactions and antioxidant activity were investigated by UV-visible spectroscopy,
fluorescence spectroscopy and free radial scavenging assay. ACN had a strong ability to quench the fluorescence of BSA in
a static manner and hydrogen bond and Van der Waals force were the dominant interactions between them. The BSA/ACN
interaction varied only slightly in different solutions. The highest binding constant was obtained in NaCl solution, followed
by PBS and dH2O, while the binding distance was increased in the order of NaCl ＜ PBS ＜ dH2O. Consequently, it was
speculated that the binding force between BSA and ACN was increased in the order of dH2O ＜ PBS ＜ NaCl. Moreover, the
ABTS radical scavenging rates of ACN alone and BSA/ACN complex were 60% and 50%, respectively, whereas the DPPH
radical scavenging rates were both 25%. Hence the three solutions had no obvious effects on free radical scavenging activity
of ACN alone and BSA/ACN complex.

Key words: bovine serum albumin, anthocyanin, fluorescence spectroscopy, UV-Vis spectroscopy, antioxidant activity