Beta-1,3/1,6-glucan, preparation method therefor, and application thereof in preparing immune enhancement and anti-tumor medicine and functional food

The present invention provide a beta-1,3/1,6-glucan, a preparation method therefor, and application thereof in preparing immune enhancement and anti-tumor medicine and functional food. The preparation method comprises: drying and milling antarctic brown algae; after degreasing, water extracting, calcium chloride precipitating and anion exchanging resin purification, obtaining glucan with a beta-1,3-glucose main chain and a beta-1,6-glucose branched chain, wherein a molecular weight thereof is between 5-50 kDa. The beta-glucan prepared by the present invention has an immune enhancement activity, which is indicated by swallow of neutral red by in vitro macrophages and an NO release promoting experiment, and has a tumor growth inhibiting effect and a tumor metastasis inhibiting effect which are indicated by an in vivo animal experiment. According to the present invention, beta-1,3/1,6-glucan is prepared by using the antarctic brown algae; is characterized in richness and readily availability of raw material sources, simple preparation process, high product purity, strong bioactivity and easiness for industrialization; and has a prospect of being developed into immune enhancement and anti-tumor medicine.