Abstract

Magnolia officinalis is an important Chinese traditional herb and the M. officinalispolysaccharides are considered as their main active ingredients in the decoction. In this study,M. officinalis polysaccharides were extracted by hot water and divided into three fractions. The molecular weights of the three polysaccharides fractions ranged from 3.9 to 4.2 kDa, 4.7 to 5.4 kDa and 5.6 to 9.4 kDa, respectively. And the polysaccharides were composed of fucose, xylose, mannose, glucose, galactose and arabinose. The antioxidant assays of the polysaccharides, including scavenging activity of superoxide anion and hydrogen peroxide, 2,2-diphenyl-1-picryl-hydrazyl, reducing power, chelating effect on metal ion and the total antioxidant activity were carried out in vitro. Moreover, their anti-tumor activity in vitro was determined by MTT assay with human breast carcinoma model cell line (MCF-7). The results indicated that the polysaccharides fractions with molecular weight 3.9 to 4.2 kDa exhibited the highest antioxidant activities and the strongest cytotoxic activity in MCF-7 cells. 

Key words: Polysaccharides, Magnolia officinalis, low molecular weight, antioxidant activity.