Method for preparing an antitumor dextran using Lactobacillus confusus

• US 5,424,201 A
• Filed: 03/11/1994
• Issued: 06/13/1995
• Est. Priority Date: 05/31/1990
• Status: Expired due to Fees

• Current Assignee: Sapporo Breweries Limited (Sapporo Holdings Limited)
• Original Assignee: Sapporo Breweries Limited (Sapporo Holdings Limited)
• Inventors: Nakakita, Yasukazu, Kado, Hisao
• Primary Examiner(s): Naff, David M.
• Assistant Examiner(s): PRATS, FRANCISCO CHANDLER
• Application Number:
  US08/212,295
• Time in Patent Office: 459 Days
• Field of Search: 435/72, 435/823, 435/101, 435/103, 536/112, 536/124
• US Class Current: 435/103
• CPC Class Codes: A61P 35/00 Antineoplastic agents
• CPC Class Codes: C12N 1/205 Bacterial isolates
• CPC Class Codes: C12P 19/08 Dextran
• CPC Class Codes: C12R 2001/225 Lactobacillus
• CPC Class Codes: Y10S 435/823 Acetobacter

Abstract

Lactobacillus confusus strains capable of producing a dextran which has biological activities such as an excellent antitumor activity, etc. are disclosed. Also disclosed is a method for producing said dextran using said microorganism or dextran synthetase prepared by said microorganism.

Claims

1. A process for preparing an antitumor dextran which comprises

(a) culturing a microorganism belonging to Lactobacillus confusus selected from the group consisting of strain FERM BP-2865, strain FERM BP-2866, strain FERM BP-2867, strain FERM 2868 and strain FERM BP-2869 in a culture broth comprising a carbon source containing sucrose and a nitrogen source, said microorganism having an ability of producing a dextran having the following properties:

(1) Form;

said dextran is a white powder having no taste and no smell;

(2) Solubility;

said dextran is soluble in water, formamide and dimethylsulfoxide, but insoluble in alcohols, acetone, hexane, chloroform and carbon tetrachloride;

(3) pH of Aqueous Solution;

the aqueous solution is neutral or weakly acidic;

(4) Constituent Saccharide;

said dextran is comprised solely of glucose;

(5) Elementary analysis values;

said dextran comprises 43 to 45% of C and 6.0 to 6.3% of H;

(6) Structure;

said dextran is an α

-glucan comprised mainly of linear α

-1,6 glucoside linkages;

(7) Proteins;

said dextran contains no protein by the Lowry'"'"'s method;

(8) Molecular weight;

said dextran does not permeate through a dialysis membrane and the molecular weight is considered to be higher than 10,000 daltons;

(9) Color Reaction;

said dextran is positive to anthrone sulfuric acid reaction and phenol sulfuric acid reaction, but negative to biuret reaction, the Lowry-Folin reaction, the Elson-Morgan reaction and the idione reaction;

(10) Melting Point;

said dextran has no definite melting point;

(11) Ultraviolet Absorption Spectrum;

said dextran has no characteristic ultraviolet absorption;

(12) Infrared Absorption Spectrum;

said dextran shows a characteristic absorption of α

-glucan;

(13) ¹³ C-NMR Spectrum;

said dextran exhibits a characteristic spectrum of α

-1,6-glucan;

(14) said dextran possesses antitumor activities; and

(b) collecting said dextran from the culture broth.

2. The process according to claim 1, wherein the culture broth further comprises one or more of a phosphoric acid salt, sodium chloride, a magnesium salt, a cobalt salt or an iron salt.

3. The process according to claim 2, wherein the culture broth comprises sucrose, a nitrogen source, a phosphoric acid salt, sodium chloride, a magnesium salt, a cobalt salt and an iron salt.

4. The process according to claim 1, wherein the culturing is carried out at an incubation temperature of 15°

to 45°

C.

5. The process according to claim 1, wherein the culturing is carried out at a pH of 5 to 7.4.

6. The process according to claim 1, wherein the culturing is carried out for an incubation time of 5 to 96 hours.

7. The process according to claim 3, wherein the carbon source is sucrose in a concentration of 0.5 to 70%.

8. The process according to claim 3, wherein the culturing is carried out at an incubation temperature of 15°

to 45°

C.

9. The process according to claim 3, wherein the culturing is carried out at a pH of 5 to 7.4.

10. The process according to claim 3, wherein the culturing is carried out for an incubation time of 5 to 96 hours.

11. The process according to claim 4, wherein the culturing is carried out at a pH of 5 to 7.4.

12. The process according to claim 4, wherein the culturing is carried out for an incubation time of 5 to 96 hours.

13. The process according to claim 1, wherein the culturing is carried out at a pH of 5 to 7.

14. The process according to claim 1, wherein the culturing is carried out at a pH of 7.4.