Separation and identification of antioxidant chemical components in Diaphragma juglandis Fructus and functional evaluation in Caenorhabditis elegans

Abstract

Diaphragma juglandis Fructus (DJF) is rich in biologically active phytochemicals, exhibiting a wide range of biological activities. According to the results of antioxidant experiments in vitro, four compounds were isolated by chromatography and identified by NMR. (1′-methyl-2′-hydroxy) propane-O-α-D-glucopyranoside (1), (4′-hydroxyphenyl) methylene-O-β-D-glucopyranosyl-(4 → 1)-α-L-arabinopyranoside (2), 2-carboxy-5,7-dihydroxy-3-naphthyl-β-D-glucopyranoside (4) (CDG), neither of which have been isolated from DJF before. CDG exhibited the highest antioxidant capacity in vitro so that we used C. elegans to evaluate antioxidant capacity and examined the changes in metabolome by GC-TOF/MS. Our study showed that CDG could improve oxidative stress and prolong lifespan in C. elegans by improving the activities of antioxidant enzymes and reducing ROS and MDA content. Metabolomics analysis revealed that CDG affected various metabolic pathways (amino acid, carbohydrate, lipid metabolism) and further affected TCA cycle and energy status, thus reduced cellular oxidative stress. These results suggest that DJF could be a potential source of natural antioxidants, specifically, CDG could be used as an antioxidant ingredient in food and pharmaceutical industries.

Keywords

• Diaphragma juglandis Fructus
• Antioxidant activity
• 2-carboxy-5,7-dihydroxy-3-naphthyl-β-D-glucopyranoside
• Caenorhabditis elegans
• Metabolomics
• GC-TOF/MS