Physicochemical, structural, and functional characterization of key bioactive proteins from Coptis chinensis leaf and...

In recent years, there has been growing interest in identifying bioactive proteins from medicinal plants and elucidating their mechanisms of action. In this study, we investigated the structural, physicochemical, and functional properties of bioactive proteins extracted from Coptis chinensis, a traditional Chinese herbal medicine. Our analysis revealed that C. chinensis primarily contains proteins with molecular weights of approximately 25 kDa and 60 kDa. The 25 kDa proteins mainly consisted of chitinase, glutathione transferase, and germin-like proteins, while the 60 kDa proteins mainly consisted of β-glucosidase, pectinesterase, and several uncharacterized proteins. Proteins derived from the leaves and roots of C. chinensis also exhibited different structural and physicochemical differences, including secondary structures, tertiary structures, spectroscopic properties and thermal stabilities. Functionally, the proteins demonstrated promising attributes for potential food applications, with water holding capacity up to 12.8 g/g, oil holding capacity up to 12.7 g/g, emulsification activity up to 57.9 m²/g, and emulsification stability lasting up to 78 min. Antioxidant assays confirmed their strong antioxidant capacity, while cell culture cytotoxicity assay indicated that they had good biocompatibility and anti-inflammatory effects. These findings elucidated the structural and bioactive profiles of C. chinensis proteins, supporting their integration as functional ingredients. Future research into their stability, bioavailability, and molecular mechanisms is essential to translate these insights into industrial applications.