| PATENT ASSIGNEE'S COUNTRY | USA |
| UPDATE | 12.00 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 19.12.00 |
| PATENT TITLE |
Preparation of fagopyritols and uses therefor |
| PATENT ABSTRACT |
The present invention describes isolated Fagopyritol A1, isolated Fagopyritol A2, and isolated Fagopyritol B3. Compositions which include two or more of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, Fagopyritol B3, and D-chiro-inositol, at least one of which is an isolated Fagopyritol A1, isolated Fagopyritol A2, or isolated Fagopyritol B3, are also disclosed. Methods for preparing substantially pure Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, Fagopyritol B3, or mixtures thereof from buckwheat are also described. The fagopyritols can be used to prepare pharmaceutical compositions, the administration of which can be used to treat diabetes. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 06.05.98 |
| PATENT REFERENCES CITED |
Other References Yasui, "Dissimilarity in Low Molecular Weight Carbohydrate Composition of the Seeds of Cultivated Soybean [Glycine max (L.) Merrill subsp. max]and Wild Soybean [G. max subsp. soja (SIEB. et ZUCC.)Ohashi]," Agric. Biol. Chem., 49:933-937 (1985). Quemener et al., "Ciceritol, a Pinitol Digalactoside from Seeds of Chickpea, Lentil and White Lupin," Phytochemistry, 22:1745-1751 (1983). Obendorf et al., "Seed Desiccation Tolerance and Storability: Dependence on the Flatulence-Producing Sugars," International Workshop: Desiccation Tolerance and Sensitivity of Seeds and Vegetative Plant Tissues, South Africa, Jan. 19, 1994 (Abstract of Oral Presentation). Obendorf, "Seed Set and Cessation of Seed Growth in Buckwheat," Developing a Strategic Plan for Integrated Buckwheat Research, North Dakota State University Research and Extension Center, Jul. 21, 1994, (Abstract of Oral Presentation). Obendorf et al., "Seed Set and Cessation of Seed Growth in Buckwheat," Quarterly Report to Sponsors, Apr. 1-Jun. 30, 1994. Obendorf, "Buckwheat Pharmaceuticals: 1. Characterization," "Buckwheat Pharmaceuticals: 2. Model for Industrial Isolation," "Buckwheat Pharmaceuticals: 3. Equipment," Research Proposals to MINN-DAK Growers Ltd., Nov. 27, 1995. Ogawa et al., "A new glycoside, 1D-2-O-alpha-D-galactopyranosyl-chiro-inositol from jojoba beans", Carbohydrate Research, vol. 302: 219-221, 1997. Schweizer et al., "Low Molecular Weight Carbohydrates From Leguminous Seeds; A New Disaccharide: Galactopinitol," J. Sci. Fd Agric., 29:148-154 (1978). Schweizer et al., "Purification and Structure Determination of Three .alpha.-D-galactopyranosylcyclitols From Soya Bean," Carbo. Res., 95:61-71 (1981). Shiomi et al., "A New Digalactosyl Cyclitol From Seed Balls of Sugar Beet," Agric. Biol. Chem., 52:1587-1588 (1988). Ortmeyer et al., "In vivo D-chiroinositol Activates Skeletal Muscle Glycogen Synthase and Inactivates Glycogen Phosphorylase in Rhesus Monkeys," Nutritional Biochemistry, 6:499-503 (1995). Ortmeyer et al., "Effects of D-Chiroinositol Added to a Meal on Plasma Glucose and Insulin In Hyperinsulinemic Rhesus Monkeys," Obesity Res. 3 (Supp 4):605S-608S (1995). Horbowicz et al., "Maturing Buckwheat Seeds Accumulate Galacto-chiro-inositol Instead of Stachyose," Abstract 908, Plant Physiology, 105:S-164 (1994). Horbowicz et al., "Galactosyl-chiro-inositol in Buckwheat Seeds Correlates with Desiccation Tolerance During Maturation and Germination," Agronomy Abst., 178, (1994). Horbowicz et al., "Fagopyritol B1, O-.alpha.-D-galactopyranosyl-(1.fwdarw.2)-D-chiro-inositol, a Galactosyl Cyclitol in Maturing Buckwheat Seeds Associated with Desiccation Tolerance," Planta, 205:1-11 (1998). Szczecinski et al., "NMR Investigation of the Structure of Fagopyritol B1 from Buckwheat Seeds," Bulletin of the Polish Academy of Sciences Chemistry, 46(1):9-13 (1998). |
| PATENT PARENT CASE TEXT | This data is not available for free |
| PATENT CLAIMS |
What is claimed: 1. An isolated Fagopyritol A2 having the formula: ##STR6## 2. An isolated fagopyritol according to claim 1, wherein said fagopyritol is substantially free of one or more of galactinol, myo-inositol, digalactosyl myo-inositol, phytin, aromatic materials, cell wall particles, proteins, organic acids, amino acids, nucleic acids, and salts thereof. 3. A substantially pure Fagopyritol A2. 4. A substantially pure Fagopyritol A2 according to claim 3, wherein said Fagopyritol A2 is from about 95% to about 99% pure. 5. A composition comprised of two or more of Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, and D-chiro-inositol, wherein said composition comprises the isolated fazopyritol according to claim 1. 6. A composition according to claim 5, wherein the composition is substantially free of one or more of galactinol, myo-inositol, digalactosyl myo-inositol, phytin, aromatic materials, cell wall particles, proteins, and organic acids, amino acids, nucleic acids, and salts thereof. 7. A pharmaceutical composition for use in treating type II diabetes comprising: a pharmaceutical carrier and an isolated fagopyritol according to claim 1. 8. A pharmaceutical composition according to claim 7, wherein said pharmaceutical composition further comprises a fagopyritol selected from the group consisting of Fagopyritol B1, Fagopyritol B2, and combinations thereof. 9. A pharmaceutical composition according to claim 7, wherein said pharmaceutical composition consists essentially of said pharmaceutical carrier and said isolated fagopyritol according to claim 1. 10. A method of treating type II diabetes in a patient comprising: administering to the patient an isolated fagopyritol according to claim 1 in an effective amount. 11. A method of treating type II diabetes in a patient comprising: administering to the patient a composition according to claim 5 in an effective amount. 12. A method of treating type II diabetes in a patient comprising: administering to the patient a substantially pure Fagopyritol A2 according to claim 3 in an effective amount. 13. A method of treating type II diabetes in a patient comprising: administering to the patient a pharmaceutical composition according to claim 7 in an effective amount. 14. A method for preparing Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, or a mixture thereof comprising: contacting buckwheat with a solvent under conditions effective to produce a crude extract comprising non-fagopyritol materials and one or more fagopyritols selected from the group consisting of Fagopyritol A2, Fagopyritol B1, and Fagopyritol B2; and separating the non-fagopyritol materials from the one or more fagopyritols. 15. A method according to claim 14, wherein the buckwheat comprises buckwheat seed embryos. 16. A method according to claim 14, wherein the buckwheat is buckwheat flour. 17. A method according to claim 14, wherein the non-fagopyritol materials comprise one or more of cell wall particles, large proteins, charged materials, and aromatic materials. 18. A method according to claim 14, wherein said separating comprises: evaporating the solvent under conditions effective to condense the crude extract. 19. A method according to claim 14, wherein said separating comprises: passing the crude extract through a molecular weight cut off filter under conditions effective to remove cell wall particles and large proteins from the crude extract. 20. A method according to claim 14, wherein said separating comprises: passing the crude extract through an ion exchange material under conditions effective to remove charged materials from the crude extract. 21. A method according to claim 14, wherein said separating comprises: passing the crude extract through a polyvinylprrolidone column or an activated charcoal column under conditions effective to remove aromatic materials from the crude extract. 22. A method according to claim 14 wherein the one or more fagopyritols comprises at least two fagopyritols, and wherein said method further comprises: separating one of Fagopyritol A2, Fagopyritol B1, and Fagopyritol B2 from the at least two fagopyritols. 23. A method according to claim 22, wherein said separating one of Fagopyritol A2, Fagopyritol B1, and Fagopyritol B2 from the at least two fagopyritols is carried out chromatographically. 24. A method according to claim 23, wherein said separating one of Fagopyritol A2, Fagopyritol B1, and Fagopyritol B2 from the at least two fagopyritols is carried out on a amine-functionalized silica gel. 25. A method according to claim 23, wherein said separating one of Fagopyritol A2, Fagopyritol B1, and Fagopyritol B2 from the at least two fagopyritols is carried out using an acetonitrile:water eluent. -------------------------------------------------------------------------------- |
| PATENT DESCRIPTION |
FIELD OF THE INVENTION The present invention relates to fagopyritols and to methods for using fagopyritols. BACKGROUND OF THE INVENTION Diabetes mellitus is a major global health problem which is recognized by the World Health Organization to be reaching epidemic proportions. It is now the fourth leading cause of death in most developed countries and a disease that is increasing rapidly in countries undergoing industrialization. Estimates of worldwide diabetes prevalence have increased from 30 million in 1985 to more than 100 million in 1994. Diabetes mellitus is a disease caused by defective carbohydrate metabolism and characterized by abnormally large amounts of glucose in the blood and urine. Diabetes mellitus can eventually damage the eyes, kidneys, heart, and limbs, and can endanger pregnancy. Diabetes mellitus is usually classified into two types. Type I, or insulin-dependent diabetes mellitus ("IDDM"), formerly called juvenile-onset diabetes because it occurs primarily in children and young adults, has been implicated as one of the autoimmune diseases. Rapid in onset and progress, it accounts for about 10 to 15 percent of all cases. Type II, or non-insulin-dependent diabetes mellitus ("NIDDM"), formerly called adult-onset diabetes, is usually found in persons over 40 years old and progresses slowly. Often it is not accompanied by clinical illness in its initial stages and is detected instead by elevated blood or urine glucose levels. Diabetes is considered a group of disorders with multiple causes, rather than a single disorder. The human pancreas secretes a hormone called insulin that facilitates the entry of glucose into tissues of the body and its utilization, thus providing energy for bodily activities. In a person with diabetes, however, the entry of glucose is impaired, a result either of a deficiency in the amount of insulin produced or of altered target cells. Consequently, sugar builds up in the blood and is excreted in the urine. In the Type I diabetic, the problem is almost always a severe or total reduction in insulin production. In the Type II diabetic, the pancreas often makes a considerable quantity of insulin, but the hormone is unable to promote the utilization of glucose by tissues. With adequate treatment most diabetics maintain blood-sugar levels within a normal or nearly normal range. This permits them to live normal lives and prevents some long-term consequences of the disease. For the Type I diabetic with little or no insulin production, therapy involves insulin injections. For Type II diabetics, most of whom are at least moderately overweight, therapy is based on diet control, weight reduction, and exercise. Weight reduction appears partially to reverse the condition of insulin resistance in the tissues. If a Type II patient's blood-sugar level is still high, the physician may add insulin injections to the treatment regimen. In many cases, the need for insulin injections is not due to a deficiency in insulin but, instead, due to the patient's reduced ability to utilize insulin efficiently because of a deficiency of galactosamine D-chiro-inositol, an insulin mediator. Besides the discomfort associated with its administration by injection, the problem of controlling the dose of insulin also exists. The hypoglycemia produced by an insulin overdose may lead to tremors, cold sweat, piloerection, hypothermia, and headache, accompanied by confusion, hallucinations, bizarre behavior, and, ultimately, convulsions and coma. Therefore, it would be advantageous to control a diabetic's blood-sugar level without resort to insulin injections. The present invention is directed to providing such control. SUMMARY OF THE INVENTION The present invention relates to an isolated Fagopyritol A1, an isolated Fagopyritol A2, and an isolated Fagopyritol B3. The present invention is also directed to a composition comprising two or more of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, Fagopyritol B3, and D-chiro-inositol. The composition comprises at least one isolated Fagopyritol A1, isolated Fagopyritol A2, or isolated Fagopyritol B3. The present invention also relates to a substantially pure fagopyritol selected from the group consisting of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, and Fagopyritol B3. In another aspect, the present invention relates to a method for preparing a material selected from the group consisting of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, Fagopyritol B3, and a mixture thereof. Buckwheat is contacted with a solvent under conditions effective to produce a crude extract. The crude extract contains non-fagopyritol materials and one or more fagopyritols selected from the group consisting of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, and Fagopyritol B3. The non-fagopyritol materials are then separated from the one or more fagopyritols. The isolated fagopyritols of the present invention can be used in a pharmaceutical composition which also includes a pharmaceutical carrier. This pharmaceutical composition or, alternatively, the substantially pure fagopyritols of the present invention or the isolated fagopyritols of the present invention can be administered to a patient to treat diabetes. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1D are schematic diagrams showing the components of a buckwheat seed. FIG. 1A is a vertical section through a mature buckwheat achene. FIG. 1B is a horizontal cross section of a mature buckwheat achene. FIG. 1C is a horizontal cross section of a mature buckwheat groat (dehulled buckwheat achene). FIG. 1D is a horizontal cross section of a mature buckwheat groat showing its milling fractions and fracture planes. FIG. 2 is a gas chromatogram of trimethylsilylated soluble components extracted from embryo tissues of mature buckwheat seed with ethanol:water (1:1, v:v). The peaks are labeled as follows: (a) D-chiro-inositol, (b) myo-inositol, (c) phenyl .alpha.-D-glucoside (internal standard), (d) sucrose, (e) Fagopyritol A1, (f) Fagopyritol B1, (g) galactinol, (h) raffinose, (i) unknown, (j) unknown, (k) Fagopyritol A2, (l) Fagopyritol B2, (m) unknown (probably digalactosyl myo-inositol), (n) stachyose, and (o) Fagopyritol B3. FIGS. 3A-3C are gas chromatograms of trimethylsilylated soluble components extracted from embryo tissues of 20 DAP buckwheat seed with ethanol:water (1:1, v:v). FIG. 3A is a gas chromatogram before hydrolysis; FIG. 3B is a gas chromatogram after hydrolysis with .alpha.c-galactosidase enzyme for 23 h; and FIG. 3C is a gas chromatogram after acid hydrolysis with 2 N trifluoroacetic acid ("TFA") at 70.degree. C. for 3 h. The peaks are identified as follows: (a) D-chiro-inositol, (b) myo-inositol, (c) phenyl .alpha.-D-glucoside (internal standard), (d) sucrose, (e) Fagopyritol A1, (f) Fagopyritol B1, (g) galactinol, (k) Fagopyritol A2, (l) Fagopyritol B2, (1) galactose, (2) glucose, and (3) fructose. Trimethylsilyl ("TMS") derivatives of glucose, fructose, and galactose capture the anomeric forms of the sugars as distinct TMS products. FIG. 4 is a graph showing the fractionation of fagopyritols from buckwheat seed. Mature groats were extracted with 50% ethanol, heated at 80.degree. C. for 45 min to inactivate hydrolytic enzymes and passed through a 10,000 M.sub.r cutoff filter, and the soluble fraction was evaporated to dryness. The residue was dissolved in 5 ml of acetonitrile:water (75:25, v:v) and chromatographed on a 9.times.290 mm column filled with 3-aminopropyl bonded silica gel, 9% functionalized. Components were eluted at 0.4 ml/min gravity flow with acetonitrile:water (75:25, v:v) and chromatographed on a 9.times.290 mm column filled with 3-aminopropyl bonded silica gel, 9% functionalized. Components were eluted at 0.4 ml/min gravity flow with acetonitrile:water (75:25, v:v, for fractions 1-70; and 60:40 acetonitrile: water for fractions 71-90). One ml of each 5-ml fraction was evaporated to dryness, derivatized with trimethylsilylimidazole ("TMSI"), and analyzed by gas chromatography. A 1-ml sample of selected fractions was evaporated to dryness for enzymatic and/or acid hydrolysis. Components in each fraction are identified as follows: (a) chiro-inositol plus myo-inositol plus sucrose, (b) Fagopyritol A1, (c) unknown, (d) Fagopyritol B1, (e) Fagopyritol A2, and (f) Fagopyritol B2. FIG. 5 shows structural formulas for the galactinol series. The enzyme synthase transfers a .alpha.-galactosyl from UDP-galactose to the 3-position of D-myo-inositol to form galactinol (O-.alpha.-D-galactopyranosyl-(1.fwdarw.3)-D-myo-inositol). Galactinol serves as a galactose donor to form the raffinose series oligosaccharides in many seeds. Galactinol can also serve as acceptor to form digalactosyl myo-inositol (O-.alpha.-D-galactopyranosyl-(1.fwdarw.6)-O-.alpha.-D-galactopyranosyl-(1 .fwdarw.3)-D-myo-inositol) found in seeds of vetch (Vicia sativa L.) and other legumes (Petek et al., "Isolation of Two Galactosides of myo-Inositol from Vetch Seeds," C.R. Acad. Sci. (Paris) Serie D: Sci. Nat., 263:195-197 (1966) ("Petek I"), and Petek et al., "Purification and Properties of .alpha.-Galactosidase in Germinating Vicia sativa seeds," Eur. J. Biochem., 8:395-402 (1969) ("Petek II"), which are hereby incorporated by reference). Small quantities of higher oligomers (trigalactosyl myo-inositol and tetragalactosyl myo-inositol) may occur in legume seeds (Courtois et al., "Distribution of Monosaccharides, Oligosaccharides and Polyols," in Harborne, et al. eds., Chemotaxonomy of the Leguminosae, New York:Academic Press, Inc., pp. 207-229 (1971) ("Courtois"), which is hereby incorporated by reference). FIG. 6 is a graph showing the germination and desiccation tolerance of dehulled `Mancan` buckwheat seeds harvested at 6 to 32 days after pollination ("DAP") and germinated fresh (.largecircle.) or after rapid drying at 12% relative humidity ("RH") over a saturated solution of LiCl (.circle-solid.). Germination was recorded at 10 d at 25.degree. C. on wet paper towels. FIGS. 7A-7E are graphs showing the slow-desiccation induction tolerance in immature (10 DAP) dehulled seeds of `Mancan` buckwheat by incubating at 93% RH during d 1, 87% RH during d 2, 75% RH during d 3, 51% RH during d 4, 45% RH during d 5, and 33% RH during d 6. Fresh seeds and seeds after incubation for 1 to 6 d at the successive lower RH environments (over saturated solutions of various salts) were rapidly dried at 12% RH and 22.degree. C. for 1 week. After desiccation, seeds were germinated on wet paper towels at 25.degree. C. Seeds that germinated within 7 d and had normal radicle growth were considered to be desiccation tolerant. FIG. 7A shows the desiccation tolerance (.circle-solid.) and d to 50% germination (.largecircle.) as a function of d during slow drying. FIG. 7B shows amount of cyclitols D-chiro-inositol (.circle-solid.) and myo-inositol (.box-solid.) per embryo as a function of d during slow drying. FIG. 7C shows the amount of galactosyl cyclitols Fagopyritol B1 (.circle-solid.), Fagopyritol A1 (filled triangle), and galactinol (.box-solid.) per embryo as a function of d during slow drying. FIG. 7D shows the amount of digalactosyl cyclitols Fagopyritol B2 (.circle-solid.), Fagopyritol A2 (filled triangle), and digalactosyl myo-inositol (.quadrature.) per embryo as a function of d during slow drying. FIG. 7E shows the amount of sucrose (.circle-solid.) as a function of d during slow drying. FIGS. 8A-8E are graphs showing various properties as a function of d at high relative humidity (98%) incubation of fresh 10 DAP immature dehulled `Mancan` buckwheat seeds. FIG. 8A shows the desiccation tolerance (.circle-solid.) and d to 50% germination (.largecircle.) as a function of d at high relative humidity. FIG. 8B shows the amount of cyclitols D-chiro-inositol (.circle-solid.) and myo-inositol (.box-solid.) per embryo as a function of d at high relative humidity. FIG. 8C shows the amount of galactosyl cyclitols Fagopyritol B1 (.circle-solid.), Fagopyritol A1 (filled triangle), and galactinol (.box-solid.) per embryo as a function of d at high relative humidity. FIG. 8D shows the amount of digalactosyl and trigalactosyl cyclitols Fagopyritol A2 (filled triangle), Fagopyritol B2 (.circle-solid.), Fagopyritol B3 (.largecircle.), and digalactosyl myo-inositol (.quadrature.) per embryo as a function of d at high relative humidity. FIG. 8E shows the amount of sucrose (.circle-solid.) per embryo as a function of d at high relative humidity. FIGS. 9A-9J are graphs showing the loss of desiccation tolerance and changes in saccharides and cyclitols during 0 to 48 h of germination of dehulled mature `Mancan` buckwheat seeds at 25.degree. C. on wet paper towels. FIG. 9A shows the desiccation tolerance (.circle-solid.) and onset of germination (.largecircle.) as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9B shows the axis length (.circle-solid.) as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9C shows the amount of cyclitols D-chiro-inositol (.circle-solid.) and myo-inositol (.largecircle.) per axis as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9D shows the amount of cyclitols D-chiro-inositol (.circle-solid.) and myo-inositol (.largecircle.) per cotyledon as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9E shows the amount of Fagopyritol B1 (.circle-solid.), Fagopyritol A1 (.largecircle.), Fagopyritol B2 (.box-solid.), and Fagopyritol A2 (.quadrature.) per axis as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9F shows the amount of Fagopyritol B1 (.circle-solid.), Fagopyritol A1 (.largecircle.), Fagopyritol B2 (.box-solid.), and Fagopyritol A2 (.quadrature.) per cotyledon as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9G shows the amount of sucrose (.circle-solid.) per axis as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9H shows the amount of sucrose (.circle-solid.) per cotyledon as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9I shows the amount of glucose (.circle-solid.), fructose (.largecircle.), and unknown (.box-solid.) per axis as a function of h of germination on wet paper towels at 25.degree. C. FIG. 9J shows the amount of maltose (.circle-solid.), maltotriose (.largecircle.), and maltotetraose (.box-solid.) per cotyledon as a function of h of germination on wet paper towels at 25.degree. C. FIG. 10 is a graph of the amount of various fagopyritols present in various fractions separated on a 3-aminopropyl-functionalized silica gel column. The material loaded on the column was the enriched Fagopyritol B3 fraction collected from a P2 column. FIG. 11 is a graph of the amount of various fagopyritols present in various fractions separated on a 3-aminopropyl-functionalized silica gel column. The material loaded on the column was selected fractions from a P2 column. FIG. 12 is a graph of the amount of various fagopyritols present in various fractions separated on a 3-aminopropyl-functionalized silica gel column. The material loaded on the column was the extract from 50 g of whole groat flour (Birkett Mills). FIG. 13 is a graph of the amount of various fagopyritols present in various fractions separated on a 3-aminopropyl-functionalized silica gel column. The material loaded on the column was the extract from 50 g of whole groat flour (Birkett Mills). FIG. 14 is a graph of the amount of various fagopyritols present in various fractions separated on a 3-aminopropyl-functionalized silica gel column. The material loaded on the column was the extract from 50 g of whole groat flour (Birkett Mills). FIG. 15 is a graph of the amount of various fagopyritols present in various fractions separated on a 3-aminopropyl-functionalized silica gel column. The material loaded on the column was the extract from 50 g of light buckwheat flour (Minn-Dak). DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fagopyritols. Fagopyritol is a general term used herein to mean an unspecified .alpha.-galactosyl D-chiro-inositol or its salt or derivative. More particularly, the present invention relates to isolated Fagopyritol A1, particularly Fagopyritol A1s have the following Formula I: ##STR1## and salts thereof. The present invention also relates to an isolated Fagopyritol A2, particularly Fagopyritol A2s have the following Formula II: ##STR2## and salts thereof. The present invention further relates to an isolated Fagopyritol B3, particularly Fagopyritol B3s have the following Formula III: ##STR3## and salts and derivatives thereof. Salts of the Fagopyritol A1s, A2s, and B3s of the present invention can be the reaction product of a base having a pKa (i.e., -log Ka) greater than the pKa of one or more of the fagopyritols.fwdarw. hydroxyl groups, such as a metal hydroxide of alkoxide, an amonium hydroxide, or an amine (e.g. a tertiary amine, like triethyl amine). Exemplary salts are alkali metal salts, such as lithium salts, sodium salts, and potassium salts, alkali earth metal salts, such as calcium salts and barium salts, ammonium salts, sufonium salts, and phosphonium salts. Derivatives of the Fagopyritol A1s, A2s, and B3s of the present invention include, for example, the reaction products of the fagopyritols with compounds bearing a carbon having a positive charge, such as an alkyl halide, in which case the derivative is an ether of the fagopyritol, or a carboxylic acid halide (e.g., acetyl chloride) or anhydride (e.g., acetic anhydride), in which case the derivative is an ester of the fagopyritol (e.g., the acetate). As used herein, an isolated fagopyritol is one which is substantially free of other buckwheat components with which it naturally occurs. It is to be understood that the isolated fagopyritols of the present invention can be prepared by a variety of methods including, for example, by extraction from buckwheat or other natural sources, as well as by chemical synthesis. The present invention also relates to substantially pure Fagopyritol A1, substantially pure Fagopyritol A2, and substantially pure Fagopyritol B3, preferably having Formula I, II, and III, respectively, their salts and derivatives. The present invention further relates to substantially pure Fagopyritol B1, particularly fagopyritols having the following Formula IV: ##STR4## and their salts and derivatives. The present invention also relates to substantially pure Fagopyritol B2, particularly fagopyritols having the following Formula V: ##STR5## as well as their salts and derivatives. As referred to herein, substantially pure means substantially free of other compounds or materials, such as galactinol, myo-inositol, digalactosyl myo-inositol, phytin, aromatic materials (e.g. polyphenols and pigments and other colored aromatic materials), cell wall particles, proteins, and acids (e.g. organic acids, nucleic acids, and amino acids) and their salts. Typically, substantially pure fagopyritols are those having greater than about 95% purity, such as greater than about 98% purity or from about 95% to about 99% purity. As indicated above, the fagopyritols of the present invention are not limited by their method of preparation. One particularly preferred method, involves purification of the subject fagopyritols from buckwheat. Briefly, buckwheat is contacted with a solvent under conditions effective to produce a crude extract containing non-fagopyritol materials and one or more fagopyritols selected from the group consisting of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, and Fagopyritol B3. The one or more fagopyritols are then separated from the non-fagopyritol materials. This process is described in greater detail below. Any portion of the buckwheat plant (Fagopyrum esculentum) can be used in preparing the fagopyritols of the present invention. The structure of developing buckwheat seeds has been reviewed and illustrated by Obendorf et al., "Structure and Chemical Composition of Developing Buckwheat Seed," pp. 244-251 in Janick et al., eds., New Crops, New York:John Wiley & Sons (1993) ("Obendorf"), which is hereby incorporated by reference. Photographs of mature buckwheat seeds have been illustrated in reviews by Marshall et al., "Buckwheat: Description, Breeding, Production, and Utilization," Advances in Cereal Science and Technology, 5:157-210 (1982) ("Marshall") and Pomeranz, "Buckwheat: Structure, Composition, and Utilization," CRC Critical Reviews in Food Science and Nutrition, 19:213-258 (1983), which are hereby incorporated by reference. Most of the structural information in the latter reviews originated from a study of the scanning electron microscopy of the buckwheat kernel by Pomeranz et al., "Scanning Electron Microscopy of the Buckwheat Kernel," Cereal Chemistry, 49:23-25 (1972), which is hereby incorporated by reference. The embryo is positioned with the radicle (root) of the embryo at the pointed top of the buckwheat achene (the name of the mature buckwheat fruit) as shown schematically in FIG. 1A. As described by Obendorf, which is hereby incorporated by reference, the cotyledons have extended through the soft (mostly liquid) endosperm to reach the bottom of the endosperm by 8 days after pollination. The achene is attached to the raceme (name of inflorescence or flower cluster) of the mother plant by the pedicel. The embryo, including the axis and cotyledons continues to grow through the endosperm, curling around the margins of the endosperm and reaching the maximum dry weight at 16 days after pollination. The endosperm continues to accumulate dry matter (mostly starch) until 24 to 28 days after pollination. After a few more days the buckwheat grain (achene or fruit) is mature and dry. A horizontal cross-section view (see line marked "xs view" in FIG. 1A) of the mature buckwheat achene is schematically illustrated in FIG. 1B. This "top-down" view illustrates the hull (pericarp, fruit coat) as the outer layer of the achene (black with light cross-hatch markings in FIGS. 1B and 1C). The hull is a hard fibrous structure that is usually black or dark brown in color. The hull is the first layer to be removed during milling to produce dehulled groats (the true "seed" without the pericarp) (FIG. 1C). The outer part of the dehulled groat is the "skin" or seed coat (also called testa). This is a fibrous layer composed of seed coat cells with thickened cell walls and remnants of the nucellus (perisperm; 1-3 cells thick). The outermost layer of cells in the endosperm is called the aleurone layer and usually adheres to the seed coat and nucellus tissues in mature grains. The aleurone is a single layer of small cells that have thicker cell walls than those of the central endosperm cells, do not contain starch, and remain "alive" upon drying of the seed. The remainder of endosperm cells have thinner cell walls and are packed with starch granules as illustrated in Marshall, which is hereby incorporated by reference. The buckwheat embryo has an axis (circle in center) and two thin, leaf-like cotyledons that wind through the endosperm to the margin and then bend to continue along the outer part of the endosperm near the seed coat (FIGS. 1B and 1C; embryo structures in black, endosperm structures in white, and seed coat or "skin" in shaded gray). In the mature grain, the cotyledons nearly surround the endosperm. The embryo (axis plus cotyledons) remain alive in the mature dry grain. After germination, the embryo forms the buckwheat seedling. In mature dry grain, the embryo and aleurone layer cells contain all of the fagopyritols and D-chiro-inositol in the buckwheat grain. The embryo (as well as the aleurone layer) contains most of the protein and nearly all of the oil, phytin, minerals, vitamins, and rutin, but only traces of starch. Nearly all of the starch is in the endosperm, but there is no starch in the aleurone layer, the outer most layer of the endosperm. Whole groat flour contains the entire groat (FIG. 1C ) ground without separation of fractions. Because of the fibrous nature of the seed coat, larger fragments usually form during milling of buckwheat groats. The fracture plane is usually inside the layers with thick-walled cells. Likewise in wheat, oats, and barley dry milling, the bran fraction contains the pericarp (with seed coat), nucellar remnants, aleurone, and subaleurone layers. The fracture plane is between the thicker-walled subaleurone layer and the thinner-walled central endosperm in these grains. Similarly, the aleurone layer of buckwheat usually adheres to the "bran" or "skins" fraction during milling. In the bran fraction, the "seed coat" (also known as testa), or "skin" adheres to the outer of the two cotyledons, and that part of the cotyledon tears off and separates with the bran fraction (see schematic illustration of theoretical fracture planes in FIG. 1D). Not all skins have adhering cotyledon tissues. Most of the endosperm has soft thin-walled cells that form flour during milling. In some seeds, the cotyledons in the center of the endosperm are quite loose and may flake off in larger segments of "pure" cotyledon tissue. These larger fragments of the cotyledons and axis may separate into the bran fraction also, but much of the soft embryo tissue is pulverized and separates with the light flour fraction that is rich in starch. For these reasons, the bran fractions can be rich sources of fagopyritols and D-chiro-inositol. Likewise, the light flour fraction contains fagopyritols from embryo fragments embedded in the endosperm, but the concentration is reduced due to dilution with large amounts of starch. Since the embryo matures before the endosperm, embryo size varies less than endosperm size in mature grain. In smaller seeds (less endosperm), the cotyledons are in contact with more of the seed coat while in larger seeds (more endosperm) the cotyledons are in contact with less of the total seed coats. "Purified bran" without hulls in the fraction, are rich in fagopyritols, minerals, protein, and oil. Important to this description is that the embryo cells (cotyledons and axis) and the cells of the aleurone layer are the cells that contain sucrose, fagopyritols, rutin, phytin, most of the minerals, most of the vitamins, nearly all of the oil, and a high concentration of protein. Cells of the embryo and aleurone layer are "living" cells in the dry seed, but cells of the subaleurone, central endosperm, and seedcoat (testa or skin) are dead. Cells of the hull (pericarp) also are dead in a dry seed. Thus, any fraction that is rich in embryo and aleurone layer cells will be rich in these components. The central endosperm cells are predominantly starch, and, therefore, the light flour fraction is rich in starch. However, because the embryo traverses the central endosperm, much of the embryo breaks into small fragments and ends up in the light flour fraction, but more would be in the dark flour fraction (includes the skins, too) or in whole groat flour. Preferred portions of the buckwheat plant for use in preparing the fagopyritols of the present invention are the buckwheat embryo, especially the embryonic axis, or any milling fraction rich in embryo, cotyledon, axis, or aleurone layer cells including "bran" or "purified bran" milling fractions. Because of its ready availability, it has been found that buckwheat flour, such as commercial fancy buckwheat flour (preferably having about 12.3% moisture) or whole groat flour prepared from commercial whole white groats, is an excellent source of buckwheat for the isolation of fagopyritols. Alternatively, the flour can be produced from buckwheat seeds, preferably dehulled buckwheat seeds. Irrespective of the buckwheat source, extraction is improved when the buckwheat, such as buckwheat flour, is ground to a fine powder, preferably to a powder which passes through a 100-mesh sieve. The buckwheat flour can be raw or defatted, defatting being effected by mixing the raw buckwheat with a solvent for fatty acids, such as alkane solvents, preferably hexanes. Although defatting increases the efficiency of the initial extraction steps, subsequent filtration and chromatography are generally more difficult when employing defatted flour. The flour is then extracted with a suitable solvent. Suitable solvents for the extraction process include water, alcohol, and water/alcohol mixtures. Water extracts typically contain more suspended materials, probably because of the higher solubility of proteins and starch in water. Alcohol and alcohol/water extracts generally contain less suspended materials and also minimize microbial and endogenous enzyme activities during extraction. Suitable alcohols for use in alcohol and alcohol/water extraction include methanol, ethanol, isopropanol, and n-propanol, ethanol being preferred. Water/ethanol mixtures are the preferred extraction solvents. Of these, the preferred solvent mixtures are those where the ethanol-to-water volume ratio is from about 1:2 to about 2:1, more preferably about 1:1. Extraction is carried out by mixing a suitable quantity of the extraction solvent with the buckwheat flour or other buckwheat source, preferably with agitation. Agitation can be effected with any suitable means, such as with a blender, preferably having a "high shear" polytron head, a paddle mixer, or a shearing mixer. When a blender is used as the agitation apparatus, good results are obtained when the blender is cycled 10 seconds on and then 10 seconds off for 1 or 2 min. The volume of the extraction solvent used per unit weight of flour is not particularly critical to the practice of the present invention. Typically, solvent/flour ratios (ml/g) of from about 1:1 to about 200:1 are suitable, with solvent/flour ratios of from about 10:1 to about 50:1 being preferred, and solvent/flour ratios of about 20:1 being most preferred. The temperature at which the extraction is carried out is not particularly critical to the practice of the present invention. However, after hot extraction, the mixture can be too thick (due to swelling of starch present in the buckwheat) to filter or centrifuge efficiently, resulting in low volumes of extracted fagopyritols. Cold extraction at temperatures from about 4.degree. C. to about room temperature (approximately 25.degree. C.), preferably from about 10.degree. C. to about room temperature, and most preferably at about room temperature generally produces the highest yields. The duration of the extraction process depends on a number of factors, including the type and vigorousness of agitation, the shape of the container in which extraction is carried out, the solvent-to-flour ratio, the temperature at which the extraction process is carried out, the volume of the material being extracted, the fineness of the grinding (particle size) of the material being extracted, and the like. Preferably, extraction is carried out for a period of time sufficient to produce a homogeneous material. Typically, about 15 seconds to about 1 hour, preferably from about 1 to about 5 minutes, more preferably from about 1 to about 2 minutes is effective. The yield of extracted fagopyritols can frequently be increased by repeating the extraction process one, two, or more times. Typically, on the first extraction, between 85 and 95% of the fagopyritols present are extracted. The second extraction, when performed, yields an additional 8-10%, and the third extraction generally produces yet an additional 1%. After the first and optional additional extraction steps, the homogenate is permitted to settle, and the solvent is removed. Although solvent removal can be achieved by any suitable means, filtration, particularly ultrafiltration, or centrifugation yields the best results. The crude extract (e.g., the supernatant after centrifugation or the filtrate after filtration) is then preferably heated to a temperature sufficient to inactivate any alpha-galactosidase and/or other enzymes present in the buckwheat that may hydrolyze the fagopyritols. Generally, deactivation can be effected by heating the crude extract to a temperature of from about 70 to about 90.degree. C., preferably about 80.degree. C. After cooling, the crude extract is preferably clarified by filtration, concentrated by evaporation, and then further clarified by ultrafiltration. The composition of the crude extract can be monitored during the extraction process and subsequent filtration, centrifilgation, deactivation, evaporation, or clarification, by standard methods, including gas-liquid chromatography, high performance liquid chromatography ("HPLC"), spectrophotometric analysis, dye-binding protein assays, and atomic absorption analysis. If necessary, the enriched fraction of fagopyritols can be fractionated by ethanol precipitation to remove unwanted soluble carbohydrates of higher oligomeric forms (e.g., pentasaccharides and higher). Recovery of the fagopyritols can be further enhanced by removing cell wall particles and large proteins, for example, by passing the crude extract through a filter having a cut off of from about 5000 M.sub.r to about 20,000 M.sub.r, preferably about 10,000 M.sub.r. Additionally or alternatively, the fagopyritols can be further purified by removing non-carbohydrate contaminants with, for example, food-grade ion exchange resins, such as Syburn Resin (available from Aftech, Inc., Rochester, N.Y.), polyvinylpolypyrrolidone, ("PVPP") (e.g., Polyclar-VT, available from ISP Technologies, Inc., Wayne, N.J.), bentonite (e.g., KWK Bentonite agglomerated powder, available from Presque Isle Wine Cellars, North East, Pa.), and diatomaceous earth powder (available, e.g., from Celite Corporation, Lamoc, Calif.). Illustratively, charged materials can be removed from the crude extract, by passing the crude extract through an ion exchange material, such as Amberlite IRA-94 ion exchange resin and Dowex 50WX4 ion exchange resin (both available commercially from Sigma Chemical Company, St. Louis). Further purification of the fagopyritols can be effected by removing aromatic materials, such as polyphenolic materials, aromatic pigments, and other brown-colored contaminants, by passing the crude extract through a column containing a material which absorbs aromatic materials, such as polyvinylpyrrolidone ("PVP") or activated charcoal. The fagopyritols can then be precipitated by chilling the concentrated crude extract or by adding an alcohol, such as ethanol, to the concentrated extract, or both. The resulting mixture of fagopyritols and other sugars can then be separated into its component fagopyritols, for example, chromatographically. For example, chromatographic separation can be carried out on an amine functionalized silica gel or by using a carbon-celite column or both. Generally, the carbon-celite column is better at removing water-soluble low-molecular-weight colored contaminants. The preferred amine functionalized silica gel, 3-aminopropyl-functionalized silica gel, is available commercially from Sigma-Aldrich (Milwaukee, Wis.). The degree of functionalization of the silica gel is not critical to the practice of the present invention. Preferably, this silica gel is from about 5% to about 15% functionalized, and, more preferably, it is about 9% functionalized. Suitable solvents for loading the crude extract on and eluting the various fagopyritols from the 3-aminopropyl-functionalized silica gel can be readily ascertained by those skilled in the art. Preferably, the separation is carried out using an acetonitrile/water eluent. More preferably, the crude extract is loaded as an acetonitrile:water (70:30, v:v) solution and is eluted, stepwise, with 70:30 (v:v) acetonitrile:water, 60:40 (v:v) acetonitrile:water, and then 50:50 (v:v) acetonitrile:water. Subsequent to elution, the 3-aminopropyl functionalized silica gel can be regenerated by with 60:40 (v:v) acetonitrile:water. Generally, the order of elution when using a 3-aminopropyl-functionalized silica gel is as follows: monosaccharides, D-chiro-inositol, myo-inositol, sucrose, trehalose, Fagopyritol A1, Fagopritol B1, galactinol, Fagopyritol A2, Fagopritol B2, di-galactosyl myo-inositol, and Fagopyritol B3. When a celite-carbon column is employed to effect chromatographic separation, suitable columns include those which contain a mixture of carbon (e.g., Darco-G60, J. T. Baker, Phillipsburg, N.J.) and celite (e.g., Celite 545-AW, Spelco, Bellefonte, Pa.). Generally, the column material is prepared by slurrying the carbon and celite in distilled water. The slurry is then packed into a suitably sized column, and the packed column is then washed with distilled water. The crude extract can be loaded using any suitable solvent, water being preferred. The carbon-celite column can be eluted with, for example, water, alcohol (e.g., ethanol), or combinations thereof Illustratively, elution can be carried out using 50% ethanol (i.e., a 50:50 (v/v) mixture of ethanol and water). Alteratively, the elution can be carried out stepwise, first eluting with distilled water, and then eluting with a series of mixtures of ethanol and water having increasing ethanol content. For example, the column can be first eluted with distilled water, then with 5% ethanol, then with 10% ethanol, then with 20% ethanol, then with 30% ethanol, then with 40% ethanol, and then with 50% ethanol. In some cases, one or more of the elution steps can be omitted. For example, elution can proceed directly from the 20% ethanol elution to the 50% elution without conducting the 30% and 40% ethanol elutions. Alternatively, elution can be carried out using a water/ethanol gradient solventsystem. Generally, the order of elution when using carbon-celite is as follows: D-chiro-inositol, myo-inositol, monosaccharides, Fagopyritol B1, galactinol, Fagopyritol A1, trehalose, Fagopyritol B2, sucrose, di-galactosyl myo-inositol, Fagopyritol A2, and Fagopyritol B3. The composition of various fractions can be analyzed by evaporating aliquots from the fractions to dryness, derivitizing with trimethylsilylimidazole ("TMSI") in pyridine (1:1) to produce trimethylsilyl ("TMS") derivatized carbohydrates, and analyzing the TMS-derivatized carbohydrates by, for example, high resolution gas chromatography. By pooling fractions containing one particular fagopyritol and evaporated to dryness, substantially pure fagopyritol is produced. Fractions containing mixtures of fagopyritols can be rechromatographed to effect their separation. The present invention also relates to a composition which includes two or more of Fagopyritol A1, Fagopyritol A2, Fagopyritol B1, Fagopyritol B2, Fagopyritol B3, and D-chiro-inositol. Preferably, this composition includes at least one isolated Fagopyritol A1, Fagopyritol A2, or Fagopyritol B3. Illustrative compositions are those which include isolated Fagopyritol A1 and isolated Fagopyritol A2, Fagopyritol B2 and isolated Fagopyritol B3, D-chiro-inositol and isolated Fagopyritol B3, and the like. Preferably, the composition is substantially free of one or more of galactinol, myo-inositol, digalactosyl myo-inositol, phytin, aromatic materials (e.g. polyphenols and pigments and other colored aromatic materials), cell wall particles, proteins, and acids (e.g. organic acids, nucleic acids, and amino acids) and their salts. It was observed that a mixture of fagopyritols was degraded within 6 hours in the presence of human fecal bacteria under in vitro conditions in the laboratory. Therefore, it is believed that the fagopyritols pass to the lower digestive tract where they are digested by bacteria to release free D-chiro-inositol for uptake. The aforementioned fagopyritols and compositions are useful in treating diabetes in patients, such as mammals, including dogs, cats, rats, mice, and humans, by administering an effective amount of the above-described isolated fagopyritols, substantially pure fagopyritols, or compositions to such patients. For example, the substantially pure fagopyritols, the compositions, or one or more of the isolated fagopyritols of the present invention can be administered alone, or the isolated fagopyritols of the present invention can be administered in combination with suitable pharmaceutical carriers or diluents. The diluent or carrier ingredients should be selected so that they do not diminish the therapeutic effects of the fagopyritols or compositions of the present invention. Suitable pharmaceutical compositions include those which include a pharmaceutical carrier and, for example, an isolated Fagopyritol A1, an isolated Fagopyritol A2, or an isolated Fagopyritol B3. The pharmaceutical composition can, additionally, contain Fagopyritol B1, Fagopyritol B2, or both. The fagopyritols and compositions herein can be made up in any suitable form appropriate for the desired use; e.g., oral, parenteral, or topical administration. Examples of parenteral administration are intraventricular, intracerebral, intramuscular, intravenous, intraperitoneal, rectal, and subcutaneous administration. The preferred route for administration is oral. In cases where the fagopyritols are administered topically or parenterally, it is preferred that the fagopyritols be pre-hydrolyzed. Suitable dosage forms for oral use include tablets, dispersible powders, granules, capsules, suspensions, syrups, and elixirs. Inert diluents and carriers for tablets include, for example, calcium carbonate, sodium carbonate, lactose, and talc. Tablets may also contain granulating and disintegrating agents, such as starch and alginic acid; binding agents, such as starch, gelatin, and acacia; and lubricating agents, such as magnesium stearate, stearic acid, and talc. Tablets may be uncoated or may be coated by known techniques to delay disintegration and absorption. Inert diluents and carriers which may be used in capsules include, for example, calcium carbonate, calcium phosphate, and kaolin. Suspensions, syrups, and elixirs may contain conventional excipients, such as methyl cellulose, tragacanth, sodium alginate; wetting agents, such as lecithin and polyoxyethylene stearate; and preservatives, such as ethyl-p-hydroxybenzoate. Dosage forms suitable for parenteral administration include solutions, suspensions, dispersions, emulsions, and the like. They may also be manufactured in the form of sterile solid compositions which can be dissolved or suspended in sterile injectable medium immediately before use. They may contain suspending or dispersing agents known in the art. For oral administration either solid or fluid unit dosage forms can be prepared. For preparing solid compositions, such as tablets, a suitable fagopyritol or composition, as disclosed above, is mixed with conventional ingredients, such as talc, magnesium stearate, dicalcium phosphate, magnesium aluminum silicate, calcium sulfate, starch, lactose, acacia methylcellulose, and functionally similar materials as pharmaceutical diluents or carriers. Capsules are prepared by mixing the disclosed fagopyritols or compositions with an inert pharmaceutical diluent and filling the fixture into a hard gelatin capsule of appropriate size. Soft gelatin capsules are prepared by machine encapsulation of a slurry of the fagopyritol or composition with an acceptable vegetable oil, light liquid petrolatum, or other inert oil. Fluid unit dosage forms for oral administration such as syrups, elixirs, and suspensions can be prepared. The water-soluble forms can be dissolved in an aqueous vehicle together with sugar, aromatic flavoring agents, and preservatives to form a syrup. An elixir is prepared by using a hydro-alcoholic (ethanol) vehicle with suitable sweeteners, such as sugar and saccharin, together with an aromatic flavoring agent. Suspensions can be prepared with a syrup vehicle with the aid of a suspending agent, such as acacia, tragacanth, methylcellulose, and the like. When the fagopyritols or compositions are administered orally, suitable daily dosages can be based on suitable doses of free D-chiro-inositol, such as those described in U.S. Pat. No. 5,124,360 to Larner et al., which is hereby incorporated by reference. It is believed that about half of the fagopyritols as extracted is D-chiro-inositol, mostly as bound D-chiro-inositol with small amounts of free D-chiro-inositol. Therefore, suitable doses of fagopyritol are about twice the suitable doses of D-chiro-inositol. Typically, for oral administration, suitable daily doses are from about 50 mg to about 200 mg of the fagopyritol or composition per kilogram of the subject's body weight. Alternatively, the fagopyritols of the present invention can be administered orally in foodstuffs. For example, fagopyritols can be incorporated in purified form or in the form of buckwheat bran in bread, bread rolls, or other foodstuffs to form an edible product for consumption of fagopyritols. Fortification of breads, bread rolls, and other foodstuffs with extracted fagopyritols can provide a way to incorporate larger quantities of fagopyritols into a daily diet. Suitable procedures for bread preparation can be found, for example, in Brown, The Tassajara Bread Book, Boston: Shambhala Publications (1986), which is hereby incorporated by reference. For parenteral administration, fluid unit dosage forms are prepared utilizing the aforementioned fagopyritols or compositions and a sterile vehicle, water being preferred. The fagopyritol or composition, depending on the vehicle and concentration used, can be either suspended or dissolved in the vehicle. In preparing solutions, the fagopyritol or composition can be dissolved in water for injection and filter sterilized before filling into a suitable vial or ampule and sealing. Advantageously, adjuvants, such as a local anesthetic, preservative, and buffering agents, can be dissolved in the vehicle. To enhance the stability, the fluid unit dosage form can be frozen after filling into the vial, and the water removed under vacuum. The dry lyophilized powder is then sealed in the vial, and an accompanying vial of water for injection is supplied to reconstitute the liquid prior to use. Parenteral suspensions are prepared in substantially the same manner except that the fagopyritol or composition is suspended in the vehicle instead of being dissolved, and sterilization cannot be accomplished by filtration. The fagopyritol or composition can be sterilized by exposure to ethylene oxide before suspending in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in the parenteral suspension to facilitate uniform distribution of the fagopyritol or composition. Parenteral dosages can range from about 5 mg to about 200 mg of fagopyritol or composition per kilogram of the subject's body weight per day. Preferably, the daily parenteral dosage would be considerably less than the dose per kilogram of subject body weight, considering that, in oral administration, the galactose from the fagopyritols would be consumed by microbes in the digestive tract whereas, in parenteral administration the galactose would contribute to blood sugar levels. Alternatively, the fagopyritol or composition can be incorporated into a sustained release formulation and surgically implanted using conventional methods. Suitable sustained release matricies include those made of ethylene vinyl acetate and other bicompatible polymers. As indicated above, it is believed that the fagopyritols are digested in the digestive tract by bacteria to release free D-chiro-inositol for uptake. It is known that D-chiro-inositol is an anti-oxidant and, more particularly, a hydroxyl radical scavanger. Accordingly, the fagopyritol and compositions of the present invention can also be used as a source of the antioxidant D-chiro-inositol, for example, by administering, preferably orally, the subject fagopyritols and compositions to a subject. |
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