Isolation, Purification, Structral Analysis And Functional Properties Of A Polysaccharide From Plantago Asiatic L. Seeds

Plantago asiatic L. belongs to the genus Plantago L.(Plantaginaceae) and it grows widely in China. A novel polysaccharide(PLP) was isolated and characterized from the seeds of Plantago asiatic L. by hot alkali extraction and chromatographic purification using DEAE Cellulose and SephacrylTM S-400 columns. PLP has a molecular weight of 1.15 × 106 Da with a purity of 99.2%. According to monosaccharide composition analysis, PLP consisted of xylose, arabinose, glucuronic acid and galactose in a molar ratio of 18.8: 7.2: 6.1: 1. The results of methylation and GC-MS analysis, FT-IR, 1D and 2D NMR indicated that PLP was a highly branched heteroxylan of β-1, 4-linked Xylp backbone with three α-GlcAp-(1â†'3)-Araf attached to O-2 position and one α-T-linked-GlcAp and one α-Araf-(1â†'5)-Araf attached to O-3 position every eight monosaccharide residues. PLP exhibited scavenging abilities against hydroxyl, peroxyl anion, and DPPH radicals, and inhibited pro-inflammatory cytokine IL-1β, IL-6 and COX-2 gene expressions. PLP also showed significant binding capacities against cholic and chenodeoxycholic acids, suggesting its possible cholesterol lowering activity. The results demonstrated that the PLP might be further developed as functional foods and nutraceuticals.