Comparison of classical and ultrasound-assisted extraction of polysaccharides from Salvia officinalis L.

After preparation of medicine tinctures from the herbal plant Salvia officinalis by classical and ultrasound-assisted extraction with aqueous ethanol, the insoluble plant residues were subsequently treated with hot water and dilute alkali to isolate polysaccharide cell wall components. The yields of the hot water extract as well as total extracted polysaccharides were higher in the case of the ultrasound-treated plant in both laboratory and pilot plant experiments. The water-extractable polysaccharide fractions, in all cases, contained glucose, galactose and arabinose as main sugar components, whereas the alkali-extractable fractions were rich in xylans. The fractions also contained considerable amounts of proteins. The water-soluble polysaccharides may contribute to the biological activity of the plant decoction. The results indicate that the addition of a subsequent extraction step during the preparation of the herbal tincture might contribute to a better exploitation of the raw material. (C) 1999 Elsevier Science B.V. All rights reserved.