ISOLATION AND PARTIAL CHARACTERIZATION OF BIOLOGICALLY-ACTIVE POLYSACCHARIDES FROM PLANTAGO-MAJOR L

Polysaccharide fractions were isolated from Plantago Major L. leaves b y extraction with cold water, hot water and with dimethylsulphoxide (D MSO). Each of the three crude extracts obtained was further separated by ion-exchange chromatography. Only the two acidic fractions from the 50 degrees C crude extract were biologically active, demonstrated by in vitro testing of activation of the complement system and induction of tumour necrosis factor alpha (TNF-a) production from human monocyte s. One of the fractions, PM I-50 contains polysaccharide material comp rising arabinose, galactose and xylose with smaller proportions of gal acturonic acid, glucose, mannose and rhamnose. This fraction was furth er fractionated by size exclusion chromatography to give three fractio ns PM I-a, PM I-b and PM I-c. PM I-a is probably an arabinogalactan an d PM I-b is mainly a 1,4-linked xylan. The other biologically active f raction, PM II50 is composed of 75% galacturonic acid, 3% rhamnose, 6% arabinose and 8% galactose. Structure analysis indicates that PM II50 is a pectin type polysaccharide.