Cichoric acid from witloof inhibit misfolding aggregation and fibrillation of hIAPP

March 24, 2020

Title

Cichoric acid from witloof inhibit misfolding aggregation and fibrillation of hIAPP

Author

Zhuoying Luo, Guanbin Gao, Zhongjie Ma, Qian Liu, Xiaobing Gao, Xintong Tang, Zhenxing Gao, Chaoyang Li, Taolei Sun

Year

2019

Journal

International Journal of Biological Macromolecules

Abstract

The misfolding, aggregation and fibrillation of human islet amyloid polypeptide (hIAPP) has been acknowledged as a hallmark event in type-II diabetes. Hence, inhibiting the misfolding, aggregation and fibrillation of hIAPP have been accepted as a vital factor to treat the disease. Here cichoric acid was extracted from witloof to explore its inhibition effects on misfolding, aggregation and fibrillation of hIAPP. Thioflavin-T (ThT) fluorescence assay, dynamic light scattering (DLS) and atomic force microscopy (AFM) images showed that cichoric acid inhibited the aggregation and fibrillation of hIAPP in a dosage-dependent manner. Circular dichroism (CD) spectra showed that cichoric acid inhibited the misfolding of hIAPP from unfolded to β-sheet. Molecular docking and further experiments revealed interactions between hIAPP and cichoric acid. Cichoric acid could bind to K1 and R11 of hIAPP via electrostatic interaction. In addition, cichoric acid could form π-π stacking with hIAPP residues F15 and F23. These interactions inhibited the misfolding, aggregation and fibrillation of hIAPP. These results, together with cichoric acid's good cytocompatibility and significant protective effects in hIAPP lesioned cell models, not only showed that cichoric acid could be used to fight against amyloidosis, but also brought a new perspective for Chinese herbal medicine as natural compound's medical potential.

Instrument

J-1500

Keywords

Circular dichroism, Protein folding, Secondary structure, Chemical stability, Aggregation, Biochemistry