*3.6. UV-Visible Spectroscopy of PSC*

The UV-visible spectrum of PSC from *Nibea japonica* skin was determined by a Shimadzu spectrophotometer (Shimadzu, Kyoto, Japan). The lyophilized PSC samples were dissolved in 0.5 M acetic acid and then centrifuged at 12,000 rpm for 10 min at 4 ◦C. The absorbance of the supernatant was measured at different wavelengths (from 200 nm to 700 nm) to get its UV-visible spectrum.

### *3.7. FTIR Spectra of PSC*

FTIR spectra of lyophilized PSC samples were measured on a Bruker Tensor 27 FTIR spectrometer (Bruker, Rheinstetten, Germany) using the method described by previous studies. The spectra were produced with a wavelengths range from 4000 to 450 cm−<sup>1</sup> at a resolution of 1 cm−<sup>1</sup> for a single scan.
