Ultrasound-assisted extraction of water-soluble polysaccharides from the roots of valerian (Valeriana officinalis L.)

The insoluble plant residues, obtained after preparation of medicinal tinct ures from the roots of valerian (Valeriana Officinalis L.) by classical and ultrasound-assisted extraction with aqueous ethanol in a pilot plant, were subsequently treated with hot water to isolate the accessible polysacchari de cell wall components. At almost equal amounts of the hot-water extractab le material, the yields of the recovered polysaccharides were lower in the ultrasonical experiment. This is due to the fact that a part of accessible polysaccharides were already solubilised by the aqueous ethanol and recover able from the medicinal tincture. Therefore, the net yield of extracted pol ysaccharides was enhanced in the ultrasonical procedure. This fact as well as the sugar composition and structural features of the isolated polysaccha rides suggest that ultrasonication have attacked the integrity of cell wall s, released and degraded its most accessible polysaccharides (pectic polysa ccharides and starch) and increased also the extractibility of its less acc essible components - xylan, mannan and glucan. The water-soluble polysaccha ride fractions from both the conventional and ultrasonical experiments exhi bit significant immunostimulatory activities in mitogenic and comitogenic t hymocyte tests. (C) 2002 Elsevier Science B,V. All rights reserved.