Title:  Bioactive rice flour extract useful for treatment of haemophilus influenzae infections

United States Patent:  6,248,372

Assignee:  Abbott Laboratories (Abbott Park, IL)

Filed:  October 27, 1999

The present invention is directed to a rice flour extract (RFE) which can be used in the prophylaxis and treatment of bacterial infections, particularly bacterial infections caused by Haemophilus influenzae and to a method of preparing and using such an antibacterial rice flour extract. The anti-Haemophilus influenzae rice flour extract of the present invention can be prepared from commercial food grade rice flours or non-commercial food grade rice flours.

DISCLOSURE OF THE INVENTION

The present invention is directed to a rice flour extract (RFE) which can be used in the prophylaxis and treatment of bacterial infections, particularly bacterial infections caused by Haemophilus influenzae and to a method of preparing and using such an antibacterial rice flour extract. The anti-Haemophilus influenzae rice flour extract of the present invention can be prepared from commercial food grade rice flours or non-commercial food grade rice flours. For example, food grade rice flour can be obtained in large quantities from several commercial sources. Useful suppliers include the following: Comet Rice Ingredients Company of Los Angeles, Calif.; Rivland Partnership of Houston, Tex.; and California Natural Products of Lathrop, Calif. A non-food grade rice flour can be obtained from ICN Biochemicals of Aurora, Ohio.

The rice flour extract of the present invention can be obtained in the following manner with commonly available reagents and materials. After selecting a rice flour, the rice flour is extracted under heat with an extraction solution having a neutral to alkaline pH until the rice flour solution becomes cloudy but does not completely gelatinize. For the purposes of this application, "gelatinization" occurs when one is not able to separate the liquid portion of the solution from the solid portion of the solution. A person of skill in the art is able to conduct viscosity measurements to determine the point at which complete gelatinization would be about to occur. Heat is used to break apart the starch granule but not to cause complete gelatinization of the rice flour. Useful aqueous extraction solutions include, but are not limited to, phosphate buffer solution (PBS) having a pH of about 7.20; a 0.1-0.2 N ammonium bicarbonate solution having a pH of from about 7.9 to about 8.0; or a 1% ammonium hydroxide solution having a pH of about 10.4.

Desirably, the rice flour solution is heated for at least about five minutes and, more desirably, it is heated for about five minutes to about two hours. The rice flour solution is heated at a temperature of about 30^oC. to about 80^oC. More desirably, the rice flour solution is heated at a temperature of about 37^oC. to about 68^oC. and, most desirably, it is heated at a temperature of about 50^oC. to about 68^oC. The extraction solution desirably has a pH of from about 4 to about 10.4. More desirably, the extraction solution has a pH of from about 7 to about 10 and, most desirably, the extraction solution has a pH of from about 7 to about 8.5.

The extract may then be diluted with additional extraction solution to facilitate the separation of insoluble residues and the filtration of extracts. Desirably, the diluted extract is centrifuged to separate a crude extract from insoluble residues. It is also desirable that the crude extract is sterile filtered.

Claim 1 of 22 Claims

We claim:

1. A rice flour extract characterized by being soluble in water, having a molecular weight of less than or equal to about 1000 dalton, having an IC₅₀ of about 0.01 mg/mL to about 0.6 mg/mL for inhibiting the adhesion of Haemophilus influenzae to nasopharyngeal cells, and being insoluble in a solvent mixture consisting essentially of chloroform, methanol and water at a ratio of 1:1:0.2 by volume.

____________________________________________
If you want to learn more about this patent, please go directly to the U.S. Patent and Trademark Office Web site to access the full patent.