GB818336A - A new acid aminopolysaccharide and a process for the production thereof - Google Patents

Abstract

A new acid aminopolysaccharide is obtained from hog gastric mucosa by the following steps: (1) extraction of hog gastric mucosa with water; (2) treating the resulting extract with a protein precipitating agent which does not precipitate the acid aminopolysaccharide, preferably trichloracetic acid; (3) removal of the resulting precipitate e.g. by filtration; addition to the extract of a water-miscible organic solvent, for example about 1 1/2 volumes of acetone per volume of extract; (4) collection of the resulting solid; (5) suspension of the solid to about 5 per cent (w/v) in aqueous phenol of about 95 per cent concentration; (6) again collecting the solid material; (7) addition to the solid material of a buffer solution of pH between 4 and 5, e.g. 0.1M acetate buffer; (8) removal of insoluble matter; (9) one or more extraction with a water-immiscible organic polar solvent, conveniently a 1 : 1 mixture of chloroform and amyl alcohol; (10) removal of the solute from the aqueous phase, e.g. by freeze drying; (11) dissolution of the solute in an aqueous solution of a barium salt such as a 3 per cent solution of barium acetate; (12) removal of the resulting residue; (13) successive fractional additions of a water-soluble lower aliphatic alcohol such as ethanol, each addition being followed by removal of the resulting precipitate; (14) collection together of the fractions of the resulting precipitate of substantially pure acid aminopolysaccharide, preferably the fraction precipitated in the concentration range of 20-30 per cent; (15) dissolution of the collected fractions in water; (16) addition of a soluble sulphate, such as sodium sulphate; (17) removal of the resulting precipitate of barium sulphate; (18) dialysis of the remaining aqueous solution against distilled water until substantially no sulphate can be detected; (19) isolation of the acid aminopolysaccharide from solution, for example, by freeze-drying. The new acid aminopolysaccharide has the following characteristics-a relative viscosity of 1.87 in 0.5 per cent solution in 0.9 per cent sodium chloride at 37 DEG C., (a )D25 = 95 DEG \sB 1 DEG and electrophonetic mobility in phosphate buffer at pH 6.0 = -9.3 X 10-5 centimetres per second per volt in the ascending boundary and -8.9 X 10-5 centimetres per second per volt in the descending boundary, an analysis of 0.5 per cent sulphur, 34.8 per cent carbon, 5.6 per cent hydrogen, 3.2 per cent nitrogen and 55.9 per cent oxygen, 34.7 per cent hexuronic acid, 21.1 per cent hexosamine, 25.5 per cent reducing substances, 6.1 per cent acetyl groups and 1.6 per cent mineral substance. The acid aminopolysaccharide is soluble in water and gives a negative reaction to biuret, xanthoproteic, Millon, Hopkins-Cole, and Sakaguchi tests. It possesses in vitro and in vivo clearing action upon rabbit plasma, antilipemic and hypocholesterolemic action in rabbits and in man and protective action against dietary liver steatosis. A detailed example of the extraction of the acid aminopolysaccharide from hog gastric mucosa is given.