Glucans
The present invention relates to a glucan having a weight average molar mass of 15,000 to 50,000 g/mol on a single chain basis and a weight average molar mass in aqueous solution on an aggregate basis of 4 to 20×10 5 g/mol and existing in gel form in aqueous solution at a concentration ≧1% at 25° C. and neutral pH and having a melting temperature (gel to sol) of 30 to 44° C. when the glucan is dissolved in water at a concentration of 2%, methods for the production thereof, medical uses thereof, physical supports having the glucan applied thereto or impregnated thereon and in vitro methods of proliferation of skin cells which comprise contacting a population of skin cells with the glucan.
1. A method of producing a gel glucan product, said method comprising the following steps:
a) heating an aqueous solution of soluble yeast glucan molecules to a temperature of 120° C. to 130° C. and holding the solution at that temperature for 10 to 30 minutes; and
b) cooling the glucan solution to a temperature of 35° C. to 50° C., over a time period of less than 80 minutes, wherein said glucan is present in said gel glucan product at a concentration of 1 to 6% and, with a weight average molar mass on an aggregate basis of 4 to 20×10 5 g/mol and a weight average molar mass on a single chain basis of 15,000 to 50,000 g/mol, wherein the gel glucan product has a gel to sol melting temperature between 30 and 44° C.
2. The method of claim 1 wherein in step a) the aqueous solution of glucan molecules is heated to a temperature of 120° C. to 125° C.
3. The method of claim 1 wherein in step a) the glucan is held at the temperature of 120° C. to 125° C. or 120° C. to 130° C. for about 20 minutes.
4. The method of claim 1 wherein the glucan is cooled over a time period of 50 to 60 minutes.
5. The method of claim 1 wherein step a) is preceded by a formolysis step wherein a particulate glucan starting material is suspended in formic acid in order to remove β-(1,6) linked glucosyl side chains and to solubilise the particulate glucan.
6. The method of claim 5 wherein the formolysed product is filtered through a mesh of about 0.2μ.
7. The method of claim 1 , wherein the glucan has a weight average molar mass of 20,000 to 40,000 g/mol on a single chain basis.
8. The method of claim 7 , wherein the glucan has a weight average molar mass of 25,000 to 30,000 g/mol on a single chain basis.
9. The method of claim 1 , wherein the glucan is present in said gel glucan product at a concentration of 2% to 4%.
10. The method of claim 9 , wherein the glucan is present in said gel glucan product at a concentration of about 2%.
11. The method of claim 1 , wherein the glucan is derived from Saccharomyces cerevisiae.
12. The method of claim 1 , wherein the glucan is a beta glucan comprising a backbone of β-(1,3)-linked glucosyl residues and side chains comprising 2 or more β-(1,3)-linked glucosyl residues, the sidechains being attached to the backbone via a β-(1,6)-linkage.
13. The method of claim 1 , wherein the glucan is essentially free of repetitive β(1,6) linked glucosyl residues.
14. A method of assisting wound or ulcer healing or treating oral mucositis or cancer in a subject in need thereof which comprises administering to said subject the gel glucan product of claim 1 .
15. The method of claim 14 wherein said ulcer is a diabetic ulcer.
16. The method of claim 14 wherein the glucan is topically applied to a subject.