In this study, we explored the mechanism of bovine serum albumin-mediated (BSA) epigallocatechin gallate (EGCg) stabilization. Intrinsic fluorescence of BSA was used as a probe to detect interaction between EGCg, epigallocatechin, or methyl gallate and BSA. Both lifetime and intensity data showed that the quenching ability of EGCg was pH-sensitive, indicating that the protonation status and redox state of EGCg may be important to the interaction. Moreover, the galloyl moiety of EGCg was responsible for quenching, and had a stronger affinity for Trp 213 in hydrophobic pocket than for Trp 134 on BSA surface. Quenching was enhanced by the epigallocatechin group of EGCg. Competitive binding experiments using HPLC and circular dichroism provided confirmation that amino side chains around Trp 213 in the hydrophobic pocket are critical in BSA- EGCg binding. Our model of EGCg-BSA interactions improves our understanding of the likely physiological fate of this green-tea derived bioactive polyphenol.

Epigallocatechin gallate interactions with serum albumin

244th National Meeting (2012)

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