Fig 1.
The presence of key SIL components, including (A) silybin A and B, silydianin, silychristin, and isosilybin A and B, and (B) taxifolin are indicated.
Fig 2.
Spectroscopic characterization of SIL A, SIL B, and their respective nanoparticles.
(A and B) The UV − vis spectra of SIL A/Nano A and SIL B/Nano B, respectively, prepared in a final concentration of 20 μg/mL. (C and D) The fluorescence emission spectra of SIL A and SIL B, respectively, excited at different wavelengths. Further details are provided in the text.
Fig 3.
Microscopic characterization of Nano A and Nano B.
(A and B) AFM images, and (C and D) HR-TEM images of Nano A and Nano B, respectively. In AFM images the scale bars represent 500 nm.
Fig 4.
DPPH-based antioxidant activity of SIL A, SIL B, and their respective nanoparticles.
The results are calculated as a fraction of 25 µg/mL ascorbic acid.
Fig 5.
The effect of (A) SIL A, (B) SIL B, (C) Nano A, and (D) Nano B on the kinetics of human insulin amyloid fibrillation monitored by increasing fluorescence intensity of ThT.
Protein samples were incubated at 57 °C while begin stirred at 250 rpm. The ThT fluorescence signal was recorded in 20 min intervals, but for simplifying the figure, signals in the plateau phase are indicated at 1 h intervals. The solid lines show fitting developed by AmyloFit [47].
Fig 6.
The effect of SIL A/Nano A and SIL B/Nano B on (A) amyloid fibrillation and (B) surface hydrophobicity of human insulin monitored by ThT and NR fluorescence microscopies, respectively.
The protein samples were incubated under amyloidogenic condition either alone or with increasing concentrations of compounds for 15 h, followed by microscopy imaging. The scale bars represent 500 nm.
Fig 7.
The effect of SIL A, SIL B, Nano A, and Nano B on the amyloid fibrillation of
α-syn. (A-D) The kinetics of α-syn amyloid fibril formation monitored by measuring fluorescence intensity of ThT in the presence of increasing concentrations of SIL A, SIL B, Nano A, and Nano B, respectively. The solid lines show fitting developed by AmyloFit [47]. (E) AFM images of α-syn samples incubated alone or with increasing concentrations of SIL A, SIL B, Nano A, and Nano B for 96 h. The scale bars represent 500 nm.
Fig 8.
Protective effects of SIL A, SIL B, and their respective nanoparticles against cytotoxicity induced by human insulin and
α-syn aggregates measured by MTT assay. (A and B) Cytotoxicity evaluation of human insulin and (C and D) α-syn aggregates produced in the absence or presence of increasing concentrations of SIL A, SIL B, or their respective nanoparticles, respectively. #p < 0.01, significantly different from control cells. *p < 0.01, significantly different from cells exposed only to human insulin or α-syn amyloid fibrils.