Structural characterization and in vitro hepatoprotective activity of an acidic polysaccharide from Dendrobium nobile...

This study aimed to investigate the structural characterization, conformational properties, and hepatoprotectiveactivity of acidic polysaccharide (DNLPS-3) from Dendrobium nobile flower. DNLPS-3 with molecular weights of 15.65 KDa was composed of Fuc: Rha: Ara: Gal: Glc: Xyl: GalA: GlcA in a molar ratio of 0.26%: 2.38%: 4.47%: 3.55%: 0.43%: 17.84%: 69.80%: 1.26%. Structural analysis with methylation indicated that DNLPS-3 mainly contained T-Ara(f), T-Xyl(p), T-Gal(p)A, 3-Gal(p)A, 4-Gal(p)A, 3,4-Gal(p)A, 3,4-Glc(p), 2,4-Gal(p)A, 2,3,4-Gal(p), 4,6-Gal(p), 3,4,6-Gal(p). NMR results show that DNLPS-3 may be a pectin polysaccharide with →4)-α-Gal(p)A-(→main chain. In vitro experiments showed that DNLPS-3 exhibited significant hepatoprotective effects. The effect was achieved by reducing the activities of ALT and AST, suppressing the production of LDH and MDA, and enhancing the anti-oxidant activities of SOD and GSH, and the specific mechanism of its hepatoprotective effect is that DNLPS-3 up-regulates Nrf2/HO-1 pathway protein expression.