Influence of environmental pH on the interaction properties of WP-EGCG non-covalent nanocomplexes.

作者：Zixuan Dongye, Shuangling Zhang, Li Wang, Zhenru Li, Mengchen Kang, Yaru Qian, Xiaofang Cheng, Yuhang Ren, Cheng Chen · 发表于：The Journal of the Science of Food and Agriculture · 年份：2023 · DOI：10.1002/jsfa.12611 · 被引用次数：36 · 研究领域：Medicine

BACKGROUND WP-EGCG covalent conjugates and non-covalent nanocomplexes were prepared and compared using Fourier-transform infrared spectra. The pH (2.6, 6.2, 7.1, and 8.2) effect on the non-covalent nanocomplexes' functional properties and the WP-EGCG interactions were investigated by antioxidant, emulsification and fluorescence quenching, molecular docking, respectively. RESULTS The amide band decreased; the -OH peak disappeared; the antioxidant activities of WP-EGCG non-covalent complexes were 2.59- and 2.61-times stronger than WP-EGCG covalent conjugates for the DPPH and FRAP, respectively (particle size: 137 vs. 370 nm). The antioxidant activities (DPPH 27.48-44.32%, FRAP 0.47-0.63) were stronger at pH 6.2-7.1 than at pH 2.6 and pH 8.2 (DPPH 19.50% and 26.36%, FRAP 0.39 and 0.41). Emulsification was highest (EAI 181 m2 /g, ESI 107%) at pH 7.1. The interaction between WP and EGCG was stronger under neutral and weakly acidic conditions: KSV (5.11-8.95 × 102 L/mol) and Kq (5.11-8.95 × 1010 L/mol/s) at pH 6.2-7.1. Binding constants (pH 6.2 and pH 7.1) increased with increasing temperature. Molecular docking suggested that hydrophobic interactions played key roles at pH 6.2 and pH 7.1 (∆H > 0, ∆S > 0). Hydrogen bonding was the dominant force at pH 2.6 and pH 8.2 (∆H < 0, ∆S < 0). CONCLUSION Environmental pH impacted the binding forces of WP-EGCG nanocomplexes. The interaction between WP and EGCG was stronger under neutral and weakly acidic conditions. Neutral and weakly aci...