A new heteropolysaccharide from the seed husks of Plantago asiatica L. with its thermal and antioxidant properties.

A new heteropolysaccharide (PMH) with a molecular weight of 1.4 × 103 kDa was isolated from the seed husks of Plantago asiatica L. The monosaccharide composition of PMH was determined as glucose, xylose, arabinose, rhamnose, galactose and galacturonic acid with a molar ratio of 1.0 : 1.8 : 2.4 : 3.8 : 4.9 : 8.5. The backbone of PMH consisted of 1,4-ß-d-GalpA with the side chains mainly composed of 1,3-α-d-Galp and 1,2-α-d-Galp which were attached to the O-3 of GlapA. The thermal analysis using the Flynn-Wall-Ozawa (FWO) method revealed that PMH had an apparent activation energy (Ea) of 173.1 kJ mol-1. PMH experienced a major decomposition during the heating process at a temperature of 91.1 °C with a dry weight loss of 31.1%. Moreover, PMH exhibited stronger antioxidant ability than commercial psyllium, partially due to its higher content of uronic acid. The results suggested that PMH could be used in functional foods due to its structural, thermal and antioxidant characteristics.

A novel alkali extractable polysaccharide from Plantago asiatic L. Seeds and its radical-scavenging and bile acid-binding activities.

A new acidic polysaccharide (PLP) was isolated and characterized from Plantago asiatic L. seeds by hot alkali extraction and chromatographic purification using DEAE cellulose and Sephacryl S-400 columns. PLP has a molecular weight of 1.15 × 10(6) Da, and a monosaccharide composition of xylose (Xyl), arabinose (Ara), glucuronic acid (GlcA), and galactose (Gal) in a molar ratio of 18.8:7.2:6.1:1. The results of methylation analysis, FT-IR, and 1D and 2D NMR indicated that PLP was a highly branched heteroxylan of ß-1,4-linked Xylp backbone with three α-GlcAp-(1→3)-Araf attached to the O-3 position and one α-T-linked-GlcAp and one α-Araf-(1→5)-Araf attached to the O-2 position every eight monosaccharide residues. PLP exhibited scavenging abilities against hydroxyl, peroxyl anion, and DPPH radicals in vitro and showed significant binding capacities against cholic and chenodeoxycholic acids, suggesting its possible cholesterol-lowering activity. The results demonstrated the potential use of PLP in functional foods and nutraceuticals.