Valorization and evaluation of acidic and neutral polysaccharides from Panax ginseng processing residues for the...

Ginsenoside extraction generates notable quantities of underutilized by-products, which hold substantial potential for sustainable resource recovery and valorization in bioactive compound development. In the present study, acidic and neutral polysaccharides (GAP and GNP) were isolated and characterized from ginseng-processing byproducts using diethylaminoethyl cellulose-52 (DEAE-52) chromatography. Structural analysis revealed that GAP (12.7 kDa) was an acidic heteropolysaccharide containing uronic acid, whereas GNP (1.15 kDa) consisted of glucose, arabinose, and galactose. Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed α-d-glucopyranose conformations and amorphous structures. In vitro, GNP exhibited superior 2,2-diphenyl-1-picrylhydrazyl (DPPH)/2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) scavenging (91.94 % / 66.52 %), while GAP showed stronger hydroxyl/superoxide radical scavenging (42.51 % / 61.27 %) and tyrosinase inhibition. In vivo, both GNP and GAP attenuated oxidative stress in mice with d-galactose-induced aging mice by restoring skin hydroxyproline levels, reducing malondialdehyde levels, and enhancing superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. Histopathological analysis demonstrated that both fractions, particularly GNP, improved dermal thinning, collagen fiber disorder, and type I collagen reduction. Importantly, no toxicity or adverse effects were observed, confirming their biocompatibility and potential as nutraceutical agents to combat oxidative skin aging.