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The anti-aging activities on Caenorhabditis elegans of a polysaccharide, O -acetyl glucomannan (LPR), purified from roots of Lilium davidii var. unicolor Cotton, were assessed by observing the mean lifespan, reproduction, pharyngeal pumping and stress response on nematodes. Additionally, the fluorescence intensity of lipofuscin and the level of reactive oxygen species (ROS) were detected. Also the activities of superoxide dismutase (SOD), catalase (CAT) and contents of malondialdehyde (MDA) were determined by the kit method. The results showed that LPR effectively delayed the aging of C. elegans in a dose-dependent manner. When the concentration reached 4 mg/mL, LPR extended the mean lifespan of C. elegans by up to 40%, 61% (P < 0.01) and 50% (P < 0.05) under normal, thermal and oxidative stress culture conditions, respectively. Moreover, LPR remarkably increased the reproduction duration of the nematodes at a concentration of 1 mg/L, and significantly decreased the ROS and lipofuscin level of C. elegans in three dosage groups. Further study illustrated that LPR at 4 mg/mL strongly increased the activity of SOD and CAT by 39.03% (P < 0.01) and 41.89% (P < 0.05), and decreased the lipid peroxidation of MDA level in C. elegans by 52.59% (P < 0.005) compared to a control. It was inferred that LPR provided stress resistance to heat and oxidation, and prolonged the lifespan of wild type N2 C. elegans mainly by elevating the function of nematode antioxidant defense systems and by scavenging free radicals. These findings provided evidence for the anti-aging properties of this polysaccharide from L. davidii. Unlabelled Image [ABSTRACT FROM AUTHOR]

A polysaccharide (LPR) was separated from the roots of Lilium davidii var. unicolor Cotton with hot water extraction, ethanol precipitation, and purification by anion-exchange and gel-permeation chromatography. LPR was characterized. The weight-average molecular weight (M W) of LPR was 5.12 × 104 g/moL. Glucose and mannose comprised LPR with a molar ratio of 2.9:3.3. IR, NMR and methylation analysis showed that LPR was a natural O -acetyl glucomannan, the backbone mainly contained β-(1 → 4)-linked d -glucopyranosyl and β-(1 → 4)-linked D-mannopyanosyl, and the branches probably linked at O-2 and/or O-3 of the mannosyl and glucosyl residues. The acetyl groups mainly attached at O-2 or O-3 of mannosyl residues. X-ray diffractometric (XRD) analysis and scanning electron microscopy (SEM) analysis revealed that LPR was a semi-crystalline substance with porous lamellar structure. Bioassays in vitro indicated that LPR had distinct scavenging activities on hydroxyl radical and DPPH radical. These findings provided a reference for functional underutilization roots of L. davidii as natural antioxidant in food and pharmaceutical industry. Unlabelled Image • First report structure and bioactivities of polysaccharide (LPR) purified from the roots of L. davidii. • LPR was a glucomannan with O -acetyl group attached. • LPR was a semi-crystalline substance with porous lamellar structure. • LPR to scavenge hydroxyl radical stronger than that of Vc (especially the concentration < 0.3 mg/mL). [ABSTRACT FROM AUTHOR]