Search

Gentiana dahurica Fisch. (G. dahurica) is one of the legitimate sources of Qinjiao in Traditional Chinese Medicine (TCM) and grows on high-altitude plateaus. Plants develop unique biochemical accumulations to resist plateau conditions, especially the strong UV irradiation. Thus, this study aimed to investigate the polysaccharide of G. dahurica (GDP), its structure and its activity against UVB irradiation. Four GDPs were isolated and two of them were subjected to structural elucidation. The results suggested that GDP-1 has 53.5 % Ara and 30.8 % GalA as its main monosaccharides, with a molecular weight (Mw) of 23 kDa; the GDP-2 has 33.9 % Ara and 48.5 % GalA, with a Mw of 82 kDa. Methylation and NMR spectroscopy analysis revealed that GDP-1 contains →5)-α-Ara f -(1 → 5)-α-Ara f -(1 → 3,5)-α-Ara f -(1 → 3,4)-α-Gal p A-(6-OMe)-(1→ as the main chain, the branches of GalA (with esterification), and the terminal Ara; the GDP-2 contains →4)-α-Gal p A-(1 → 4)-α-Gal p A-(6-OMe)-(1 → 5)-α-Ara f -(1 → 3,5)-α-Ara f -(1→ as the main chain, the branches of →5)-α-Ara f -(1–5)-α-Ara f , and the terminal GalA. Both GDP-1 and GDP-2 exhibited concentration-dependent antioxidant activity against DPPH, ABTS and hydroxyl radicals. Moreover, GDPs significantly attenuated the decreases in viability and proliferation of HaCaT cells after UVB irradiation. They can scavenge reactive oxygen species (ROS) and improve the activities of endogenous antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH). The potential mechanism explored by flow cytometry assays of cell apoptosis and cell cycle distribution suggested that GDPs exert protective effects against UVB irradiation by reducing ROS and attenuating S phase cell arrest. In brief, the GDP-1 and GDP-2 are α-1,3- and α-1,4- arabinogalacturonan, respectively. The high content of Ara could be attributed to biochemical accumulation in resisting to the plateau environment and to prevent UVB irradiation-related damage in cells. These findings provide insight into authentic medicinal herbs and the development of GDPs in the modern pharmaceutical and cosmetics industry. [Display omitted] [ABSTRACT FROM AUTHOR]

The dried root of Pueraria mirifica (P. mirifica) is an edible foodstuff widely used in Asian countries. P. mirifica is known for its high starch content. The isolation of polysaccharides from high-starch plant parts is challenging due to the interference of starch. Therefore, this study aimed to develop a technique for isolating and investigating the structure and activity of non-glucan polysaccharides from P. mirifica (PMP). An effective starch removal process was developed using α-amylase hydrolysis and thorough membrane dialysis. Four non-glucan polysaccharides were isolated, and PMP-2 was subjected to structural elucidation. The results indicated that PMP-2 has a molecular weight of 124.4 kDa and that arabinose and galactose are the main components, accounting for 27.8 % and 58.5 %, respectively. Methylation and NMR analysis suggested that PMP-2 is an Arabinogalactan composed of 1,6-linked Gal p and 1,4-linked Gal p as the main chain, with arabinan and rhamnose as side chains. Furthermore, PMP-C and PMP-2 exhibited concentration-dependent antioxidant activities against DPPH, ABTS, and hydroxyl radicals and certain immunomodulatory activities related to the release of NO, TNF-α and IL-6. These findings suggest that PMP-2 has potential therapeutically active ingredient in functional foods. The developed method successfully removed starch and isolated non-glucan polysaccharides from the high-starch content plant P. mirifica and can be applied to other high-starch plants. [Display omitted] [ABSTRACT FROM AUTHOR]

The swollen culm (also known as Jiaobai) of Zizania latifolia is formed by the smut Ustilago esculenta invades the Z. latifolia. The new tissue formed due to the symbiotic relationship has entices the attention of researchers to study its polysaccharide structure along with biological evaluation. Five fractions of polysaccharides were obtained owing to hot water extraction, alcoholic precipitation, and chromatographic purification. Bioactivity assays showed that ZLPs have good antioxidant, hypoglycemic activities and protective activity against oxidative damage. The ZLP-1 and ZLP-2 were determined to be neutral polysaccharides with high purity, exhibiting propitious bioactivity, consequently they were subjected to indispensable structural characterization. These results showed that ZLP-1 has molecular weight (Mw) of 103 kDa and glucose (Glc) (76.68 %) as the primary monosaccharide; the ZLP-2 has Mw of 122 kDa and galactose (Gal) (41.04 %) and arabinose (Ara) (27.12 %). Structural elucidation by methylation and nuclear magnetic resonance (NMR) analysis suggested ZLP-1 is a glucan, with →3)-β-Glc p -(1→3)-β-Glc p -(1→4)-β-Glc p -(1→4)-β-Glc p -(1→3,6)-β-Gal p -(1→3)-β-Glc p -(1→ as the mainchain and the terminal Ara f and Glc p ; the ZLP-2 is a Galactoxylan, with →3,4)-β-xyl p -(1→3)-β-Gal p -(1→3,6)-β-Gal p -(1→3,6)-β-Gal p -(1→ as the mainchain and the terminal Ara f and Glc p. The structural arrangements provide a chemical basis for understanding the nutritional and pharmacological activities of polysaccharides from Zizania latifolia. [ABSTRACT FROM AUTHOR]