PURPOSE: To obtain a novel polysaccharide substance having specific physical and chemical properties, extremely low toxicity and excellent antitumor activity, by culturing a microbial strain belonging to Lactobacillus genus.
CONSTITUTION: A microbial strain belonging to Lactobacillus genus and capable of producing polysaccharide substance LK-100 (e.g. Lactobacillus sp. Glico 1569, FERM P-8887, etc.) is cultured to obtain the objective polysaccharide substance LK-100 having the following physical and chemical properties: Elemental analysis, C=38.46%, H=6.35%, N=0.04%, O=55.15%; specific rotation, [α]25D=+72.5° (C=0.5%); melting point, discoloration takes place from about 230°C, begins to melt at about 260°C and decomposes at about 280°C to form dark brown material; solubility, soluble in water and insoluble in methanol, ethanol, acetone and ether; liquid nature, pH of 0.5% aqueous solution is about 5.0; color of the substance, freeze-dried product is white fibrous substance; composition of constituent sugar, glucose:galactose=1:0.8; infrared absorption spectrum (KBr method), shown in the figure.
KAWAMOTO HISASHI
MIZUTANI TAKEO
KOJIMA SETSURO
TAMURA SHINJI
NAGANUMA KIYOSHI
RIKAGAKU KENKYUSHO