Noncovalent Interaction of Lactoferrin with Epicatechin and Epigallocatechin: Focus on Fluorescence Quenching and Antioxidant Properties

Junliang Chen; Shuhua Ma; Xin Chen; Xin Dai; Li Zhang; Yunxia Yuan; Linlin Li; Hui Zhang; Gangtian Liu; Guangyue Ren; Xu Duan; Qinggang Xie; Weiwei Cao

doi:10.1021/acsomega.3c06560

Noncovalent Interaction of Lactoferrin with Epicatechin and Epigallocatechin: Focus on Fluorescence Quenching and Antioxidant Properties

ACS Omega. 2023 Oct 25;8(44):41844-41854. doi: 10.1021/acsomega.3c06560. eCollection 2023 Nov 7.

Authors

Junliang Chen¹, Shuhua Ma¹, Xin Chen¹, Xin Dai¹, Li Zhang¹, Yunxia Yuan¹, Linlin Li¹, Hui Zhang¹, Gangtian Liu¹, Guangyue Ren¹, Xu Duan¹, Qinggang Xie², Weiwei Cao¹

Affiliations

¹ College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, Henan 471023, China.
² Heilongjiang Feihe Dairy Co., Ltd., Beijing 100015, China.

Abstract

Lactoferrin (LF) from bovine milk possesses antioxidant activity, immune regulatory and other biological activities. However, the effects of epicatechin (EC) and epigallocatechin (EGC) interacting with LF on the antioxidant activity of LF have not been investigated. Therefore, this study aimed to explore their interaction mechanism and the antioxidant activity of LF. UV spectra revealed that EGC (100 μM) induced a higher blue shift of LF at the maximum absorption wavelength than that of EC (100 μM). Fluorescence spectra results suggested that LF fluorescence was quenched by EC and EGC in the static type, which changed the polarity of the microenvironment around LF. The quenching constants K_sv (5.91 × 10³-9.20 × 10³) of EC-LF complexes at different temperatures were all higher than that (1.35 × 10³-1.75 × 10³) of the EGC-LF complex. EC could bind to LF via hydrophobic interactions while hydrogen bonding and van der Waals forces drove the binding of EGC to LF. Both the EC-LF complex and EGC-LF complex could bind to LF with one site. EGC formed more hydrogen bonds with LF than that of EC. The antioxidant activity of LF was increased by the high addition level of EC and EGC. These findings would provide more references for developing LF-catechin complexes as functional antioxidants.