Low molecular weight glycoprotein from Amomum villosum Lour.: Preparation of directed enzymatic hydrolysis, structural identification and antioxidant activity in Caenorhabditis elegans based on metabolomics

Glycoproteins are critical active ingredients in Amomum villosum Lour. (AV), and low molecular weight glycoproteins had higher nutritional value than high molecular weight glycoproteins. In this study, low molecular weight AV glycoprotein (AG) was selectively prepared through different enzymatic hydrolysis, ethanol fractionation and purification, and it was found that the AV crude extract obtained by papain enzymatic hydrolysis had excellent in vitro antioxidant activity, and the in vitro antioxidant activity of alcohol soluble AV crude extract (low molecular weight) was superior to that of alcohol insoluble AV crude extract. AG was a glycoprotein mainly composed of glucan with a molecular weight of 215, 577 Da, which had significant antioxidant capacity by scavenging DPPH and ABTS free radicals in vitro , significantly reducing the MDA levels in Caenorhabditis elegans ( C. elegans ), and increasing antioxidant enzyme related T-SOD, GSH-Px and CAT levels, exerting potential in vivo antioxidant activity. In addition, AG significantly regulated the metabolite levels in C. elegans , which nucleoside metabolism, glutathione metabolism and pentose phosphate pathway were key metabolic pathways for enhancing the antioxidant ability. These results provided reference for elucidating the metabolic mechanism of AG enhancing antioxidant capacity and the development of antioxidant related functional foods. The data that support the findings of this study are available from the corresponding author upon reasonable request.