TRI-VALENT CHROMIUM COMPOUNDS, COMPOSITIONS AND METHODS OF USE

FIELD OF THE INVENTION

[0001] This application claims the benefit of priority from provisional patent application serial number 60/791,286, filed April 12, 2006, which is incorporated in its entirety by reference herein.

[0002] The present invention relates to novel trivalent chromium complexes, which possess the ability to improve insulin sensitization, glucose tolerance, blood lipid profiles, and lean body mass through increased chromium bioavailability, efficacy and safety.

BACKGROUND OF THE INVENTION

[0003] Trivalent chromium (Cr ⁺³ ) has long been known to be essential for proper insulin function and, thus, plays a vital role in protein, fat and carbohydrate metabolism. In the U.S., studies show that the diets of nine out of 10 Americans are deficient in chromium, while chromium levels are known to decline with age. Stress, exercise and pregnancy are known to increase chromium losses from the body. Chromium deficiency can lead to symptoms associated with adult-onset diabetes, obesity and cardiovascular disease. In studies, supplemental trivalent chromium has improved blood sugar levels or other symptoms in people with glucose intolerance, type 1 diabetes, type 2 diabetes, steroid-induced diabetes and gestational diabetes. Chromium is also known to increase lean body mass, improve blood lipid profiles and lower blood pressure levels. Chromium bioavailability and biological activity are dependent upon the ligand to which chromium is bound. Inorganic chromium chloride, for example, is poorly absorbed by the body and only certain forms, such as niacin-bound chromium, are known to potentiate the action of insulin. Elucidating the structure, function and mode of action of the biologically active form of chromium, however, has proved enigmatic. (Mertz W. Chromium in human nutrition: a review. /. Nutr. 1993; 123:626-633; Lukaski H. C. Chromium as a supplement. Annu. Rev. Nutr. 1999; 19:279- 301.)

[0004] There are a number of proposals that have been developed on the composition of biologically active chromium, called glucose tolerance factor (GTF). Walter Mertz has suggested that brewer's yeast contained a biologically active form of trivalent chromium comprised of Cr ³⁺ , glycine, glutamate, cysteine, and nicotinic acid, which strongly potentiated the action of insulin and possess an ultraviolet absorbance maximum at about 260 nm. (Schwartz K, Mertz W: A glucose tolerance factor and its differentiation from factor 3.

Arch Biochem Biophys 72: 515-518, 1957; Topher EW, Mertz W, Polansky MM, Roginski EE, Wolfe WR: Preparation of chromium containing material of glucose tolerance factor activity from Brewer's yeast extracts and by synthesis. /. Agricul Food Chem 25: 162-166, 1977.)

[0005] John Vincent has proposed a naturally occurring oligopeptide, low-molecular- weight chromium-binding substance (LMWCr) or chromodulin. Chromodulin has been proposed to activate insulin receptor kinase activity. The oligopeptide possesses a molecular weight of 1500 Da and is comprised of four types of amino acid residues: glycine, cysteine, glutamate and aspartate. (Vincent J. B: The quest for the molecular mechanism of chromium action and its relationship to diabetes. Nutr. Rev. 58, 2000.)

[0006] Taken together, the ligands of four amino acids, glycine, cysteine, glutamate and aspartate, and niacin are important for bioactive chromium complexes. (Yamamoto A., Wada O, Ono T: Isolation of a biologically active low-molecular-mass chromium compound from rabbit liver. Eur. J. Biochem. 165: 627-631, 1987; Davis CM, Vincent JB, Chromium oligopeptide activates insulin receptor tyrosine kinase activity. Biochemistry 36: 4382-4385, 1997.)

[0007] A third proposal supports the use of the amino acid histidine for GTF activity, U.S. Patent No. 6,689,383, which is incorporated by reference in its entirety. Chromium histidine is said to be absorbed at least 50 percent better than chromium picolinate. In tests, men and women absorbed an average 3.1 μg of chromium from the chromium-histidine complex, compared with 1.8 μg from chromium picolinate, 0.4 μg from chromium chloride and 0.2 μg from chromium polynicotinate.

[0008] Alternatively, Yang et al. have shown the use of triphenylalanine as a ligand for a bioactive form of chromium. (Yang X, Palanichamy K, Ontko AC, Rao MNA, Fang C, Ren J, Sreejayan N: A newly synthetic chromium complex - chromium triphenylalanine improves insulin responsiveness and reduces whole body glucose tolerance, FEBS Letters 579 1458 - 1464, 2005.)

[0009] Synthesis of chromium amino acid nicotinate complex with mixture of glycine, glutamic acid and cysteine has been disclosed in U.S. Patent No. 5,536,838, which is incorporated by reference in its entirety.

SUMMARY OF THE INVENTION

[0010] Disclosed herein are chromium complexes, compositions comprising chromium complexes, and methods of using these complexes to promote or improve various health conditions and functions of the body. The chromium complexes discloses herein exhibit increased chromium bioavailability and efficacy once administered to a subject.

[0011] Thus, in one aspect, chromium complexes having two nicotinate ligands and a third ligand are disclosed. Typically, the third ligand is another carboxylate ligand. In some embodiments, the third ligand is an amino acid (e.g., glycine, alanine, aspartic acid, asparagine, arganine, cysteine, glutamic acid, glutamine, histidine, isoleucine, lysine, leucine, methionine, phenylalanine, proline, serine, threonine, tyrosine, tryptophan, or valine) or a compound that has alone been shown to have beneficial health benefits (e.g., hydroxycitric acid, 5-hydroxytryptophan, gallic acid, or cinnamic acid). In various embodiments, the chromium complexes are isolated and purified. In specific embodiments, the chromium complexes are chromium dinicotinate tryptophan, chromium dinicotinate 5- hydroxytryptophan, chromium dinicotinate glutamate, or chromium dinicotinate cinnamate.

[0012] In still another aspect, the chromium complexes are complexes of trivalent chromium and at least one and no more than three tyrosine or tryptophan ligands. In specific embodiments, the present invention provides chromium complexes such as chromium (III) tris(tryptophan) and chromium (III) tris(tyrosine).

[0013] In another aspect, the chromium complexes are complexes of trivalent chromium and one or more compounds extracted from plants. The plants from which these compounds are extracted are typically plants shown to have beneficial health benefits, such as genus Garcinia, Groffonia simplicifolia, cinnamon bark, gallnuts, sumac, witch hazel, tea leaves, and oak bark. In specific embodiments, the present invention provides chromium complexes such as chromium hydroxycitrate, chromium hydroxytryptophan, chromium cinnamate, and chromium gallate.

[0014] In still another aspect, disclosed herein are compositions comprising the present chromium complexes. The compositions can include a pharmaceutically acceptable carrier or a food safe carrier. The present compositions are typically water soluble and heat stable. In some embodiments, the amount of chromium complex in the composition is about 0.000001% to about 1% by weight of the total composition. In various cases, the amount of chromium that is provided in each dose of the present compositions is about 10 to about 1000

μg. In various embodiments, the compositions disclosed herein are formulated as a pill, tablet, capsule, powder, lozenge, gum, liquid, solution, dietary supplement, food, beverage, or topical composition.

[0015] In yet another aspect, methods are disclosed for improving or promoting healthy insulin function, glucose tolerance, blood sugar levels, blood lipid levels, blood pressure levels, inflammation, and/or lean body mass comprising administering a therapeutically effective amount of a composition as disclosed herein to a subject in need thereof, wherein the composition provides sufficient chromium to the subject and improves or promotes one or more of the identified health conditions which are now known or are discovered to be responsive to chromium levels in the subject. In various embodiments, the subject is a mammal. In specific embodiments, the subject is human or swine. In alternative embodiments, the subject is avian.

[0016] Novel chromium compounds, which improve insulin sensitization, glucose metabolism or tolerance, blood lipid metabolism, bioavailability and/or safety as compared to chromium nicotinate, chromium picolinate and chromium histidine are disclosed. These compounds are evaluated in terms of solubility, in vitro insulin sensitization, stability, and absorption as compared to chromium nicotinate, chromium picolinate and chromium histidine. The most promising chromium compounds can be tested for their animal in vivo bioavailability, glucose metabolism, lipid metabolism and acute toxicity.

[0017] These present chromium compounds (alternatively called chromium complexes) include dinicotinate chromium complexes having a carboxylate ligand as a third ligand. The third ligand can be a simple carboxylate (e.g., priopionate), a carboxylate having other coordinating functionality (e.g., amino acids or hydroxy-acids), and/or a carboxylate having pi electrons available for potential secondary bonding to chromium through chromium's d- orbitals (e.g., tyrosine or tryptophan).

DETAILED DESCRIPTION OF THE INVENTION

[0018] Chromium complexes disclosed herein are complexes of chromium and one, two, or three ligands having a carboxylate functional group, such as glycine, glutamate, cysteine, aspartate, tryptophan, cinnamate, nicotinate, and the like. These complexes can be compared in various biologically assays for their ability to increase and/or influence the bioavailability and/or biological activity of chromium. By assaying these complexes, it can be determined

which ligands, if any, have any effect on the solubility, bioavailability and biological activity of chromium.

[0019] In various cases, the ligand(s) has/have the ability to bond to chromium via its carboxylate functional group as well as through pi electron-d orbital interaction. This secondary interaction between the ligand and chromium can increase the bioavailability and absorption of chromium.

[0020] In some cases, the ligand has known biological function alone. Examples include, but are not limited to, hydroxycitric acid, 5-hydroxy typtophan, gallate, and cinnamate.

Chromium Hydroxycitrate

[0021] Hydroxycitric acid (HCA) is a naturally occurring acid found in the rinds of the fruit of Garcinia cambogia, Garcinia indica, Garcinia mangostana, and Garcinia atrovirides. The dried fruit rind of G. cambogia, also known as Malabar tamarind, is commonly used in Southeast Asia (particularly southern India) as a food preservative, flavoring agent and carminative. The primary mechanism of action of (-)-HCA appears to be related to act as a competitive inhibitor of the enzyme ATP-citrate lyase, which catalyzes the conversion of citrate and coenzyme A to oxaloacetate and acetyl coenzyme A (acetyl-CoA), building blocks of fatty acid synthesis. Extensive experimental studies suggest that (-)-HCA suppresses fatty acid synthesis, lipogenesis and food intake, thus leading to weight reduction. In addition to suppression of fatty acid and fat synthesis, (-)-HCA is thought to suppress food intake via loss of appetite by stimulation of liver gluconeogenesis. Various researchers have evaluated HCA for its weight control properties, fat burning properties, lipid level lowering effect, appetite regulation, metabolic rate increase and other effects. A number of patents have been granted based on the above studies and various methods of extraction of HCA from the fruit. The isolation and chemical nature of (-)-HCA from Garcinia rind are well studied. (See, e.g., Lewis, Y.S. et al, Phytochemistry, 4, 619-625, 1965; US Pat. No. 5,656,314, which is incorporated by reference in its entirety.) Recent literature reveals that (- )-HCA acts as a glucose absorption regulator. (See, e.g., Wielinga, Y. P. et al. Hydroxycitric acid delays glucose absorption in rats, Am. J. Physiol. Gastrointest. Liver Physiol. , 288: 1144- 1149, 2005). Since HCA alone has been shown to have beneficial effects in regulating glucose absorption and in weight control, HCA complexed to chromium provides a doubly beneficial effect - through the effect of HCA and through the effect of bio available chromium.

Chromium Cinnamate or Chromium Gallate

[0022] Cinnamic acids are widely distributed in plant kingdom and are reported as antioxidants. These compounds impart nutraceutical traits to foods by way of their abilities to serve as cellular antioxidants, anti-inflammatory agents or inhibitors of enzymes involved in cell proliferation. These activities are important in ameliorating chronic diseases such as cancer, arthritis and cardiovascular disease, which in some cases may be caused by free radicals. Because of proven safety of cinnamic acids like caffeic acid and phenolic benzoic acids like gallic acid, chromium complexes of cinnamic acid and gallic acid may have insulin sensitizing capacity.

Chromium 5-Hvdroxytrvptophan Complex

[0023] 5-Hydroxytryptophan (5-HTP) is a natural compound isolated from the seeds of an African plant called Griffonia simplicifolia. Substances which increase brain serotonin (5- hydroxytryptamine, 5-HT) are effective anorectic agents to help obese patients lose weight and to decrease cravings for sweets and carbohydrates. Experimental studies have proven that 5-HTP increases brain serotonin (5-HT), a neurotransmitter involved in appetite control, sleep and mood. Chromium complexes of 5-hydroxytryptophan may exhibit these same beneficial effects in addition to the beneficial effects due to bioavailable chromium.

Screening of Novel Chromium Complexes

[0024] Three phases of screening of chromium compounds are conducted. Phase I involves synthesis and chemical/physical characterization of the novel chromium complexes in comparison to know (reference or control) compounds. Phased II includes in vitro insulin sensitization, absorption and stability tests on all of the synthesized chromium complexes as compared to reference or control compounds, such as chromium nicotinate, chromium picolinate, chromium histidine and chromium triphenylalanine. Phase III includes in vivo bioavailability, glucose metabolism, lipid metabolism and acute toxicity, and be carried on to the most promising compounds from Phase II.

[0025] Still another set of chromium complexes disclosed herein are chromium having three different carboxylate ligands. By varying ligands from nicotinic acid, glutamate, cystinate, aspartate, argininate, tyrosine and tryptophan, at least 30 possible chromium complexes are produced. Each of these compounds can be assessed for their ability to provide chromium in a bioavailable form using the assays disclosed herein.

[0026] Some chromium compounds contemplated include, but are not limited to, the following: Chromium dinicotinate tryptophan; Chromium dinicotinate tyrosine; Chromium dinicotinate hydroxycitrate; Chromium dinicotinate cinnamate; Chromium dinicotinate gallate; Chromium dinicotinate 5-hydroxytryptophan; Chromium dinicotinate aspartate; Chromium dinicotinate glutamate; Chromium dinicotinate arginate; Chromium tris(tryptophan); Chromium tris(tyrosine); Chromium tris(hydroxycitrate); Chromium tris(5- hydroxytryptophan); Chromium tris(cinnamate); and Chromium tris(gallate).

Compositions of Chromium Complexes

[0027] The chromium complexes disclosed herein can be incorporated into a composition. These compositions can further comprise a pharmaceutically acceptable carrier or excipient or a food safe carrier or excipient. The amount of the chromium complex is typically about 0.000001% to about 1% by weight of the total composition. The chromium complex can be about 0.00001% to about 0.5%; about 0.00001% to about 0.1%; about 0.001% to about 0.5%, or about 0.001% to about 0.01% by weight.

[0028] The compositions disclosed herein typically provide a total amount of chromium upon administration to a subject in need of about 10 μg to about 1000 μg. The amount of chromium provided can be about 20 μg to about 500 μg; about 20 μg to about 250 μg; about 100 μg to about 750 μg; about 250 μg to about 750 μg; or about 500 μg to about 1000 μg.

[0029] An "effective amount" of the disclosed complexes refers to the amount or quantity of the complex, which is sufficient to elicit the required or desired prophylactic or therapeutic response, or in other words, the amount which is sufficient to elicit an appreciable biological response when administered to a subject. For example, an effective amount of a chromium complex as disclosed herein may reduce blood pressure or blood sugar levels in a subject. The actual effective amount for a particular subject can be readily determined by a person of ordinary skill in the art by various dosing tests and evaluations of chromium complexes for their effect on, for instance, blood pressure levels, cholesterol levels, and the like.

[0030] The compositions disclosed herein comprise a pharmaceutically acceptable carrier or a food safe carrier. Such carriers can be those that are approved by regulatory agencies, such as the U.S. Food and Drug Administration and its national counterparts or those carriers generally regarded as safe (GRAS) in the relevant industry. Exemplary carriers include phosphate buffered saline solution, and 5% aqueous solution of dextrose. The present compositions can be in the form of an emulsion, such as an oil/water or water/oil emulsion,

and various types of wetting agents and/or adjuvants, that are approvable by a competent regulatory authority as suitable for administration. Suitable pharmaceutical carriers and formulations are described in Remington's Pharmaceutical Sciences, 19th Ed. (Mack Publishing Co., Easton, 1995).

[0031] Preferred pharmaceutical carriers depend upon the intended mode of administration of the active agent. Typical modes of administration include enteral (e.g., oral) or parenteral (e.g., subcutaneous, intramuscular, intravenous, intraperitoneal or intrathecal injection; or topical, transdermal, or transmucosal including intrapulmonary administration). Pharmaceutically acceptable ingredients are well known for the various types of compositions and may be for example binders such as natural or synthetic polymers, excipients, lubricants, surfactants, sweetening and flavoring agents, coating materials, preservatives, dyes, thickeners, adjuvants, antimicrobial agents, antioxidants and carriers for the various formulation types. Nonlimiting examples of binders useful in a composition described herein include gum tragacanth, acacia, starch, gelatin, and biological degradable polymers such as homo- or co-polyesters of dicarboxylic acids, alkylene glycols, polyalkylene glycols and/or aliphatic hydroxyl carboxylic acids; homo- or co-polyamides of dicarboxylic acids, alkylene diamines, and/or aliphatic amino carboxylic acids; corresponding polyester-polyamide-co-polymers, polyanhydrides, polyorthoesters, polyphosphazene and polycarbonates. The biological degradable polymers may be linear, branched or crosslinked. Specific examples are poly-glycolic acid, poly-lactic acid, and poly-d,l-lactide/glycolide. Other examples for polymers are water-soluble polymers such as polyoxaalkylenes (polyoxaethylene, polyoxapropylene and mixed polymers thereof, poly-acrylamides and hydroxylalkylated polyacrylamides, poly-maleic acid and esters or -amides thereof, poly- acrylic acid and esters or -amides thereof, poly-vinylalcohol und esters or -ethers thereof, poly-vinylimidazole, poly-vinylpyrrolidon, und natural polymers like chitosan.

[0032] Nonlimiting examples of excipients useful in a composition described herein include phosphates such as dicalcium phosphate. Nonlimiting examples of lubricants use in a composition described herein include natural or synthetic oils, fats, waxes, or fatty acid salts such as magnesium stearate.

[0033] Surfactants for use in a composition described herein can be anionic, anionic, amphoteric or neutral. Nonlimiting examples of surfactants useful in a composition described herein include lecithin, phospholipids, octyl sulfate, decyl sulfate, dodecyl sulfate, tetradecyl sulfate, hexadecyl sulfate and octadecyl sulfate, Na oleate or Na caprate, 1-

acylaminoethane-2- sulfonic acids, such as l-octanoylaminoethane-2- sulfonic acid, 1- decanoylaminoethane-2- sulfonic acid, l-dodecanoylaminoethane-2- sulfonic acid, 1- tetradecanoylaminoethane-2- sulfonic acid, l-hexadecanoylaminoethane-2- sulfonic acid, and l-octadecanoylaminoethane-2- sulfonic acid, and taurocholic acid and taurodeoxycholic acid, bile acids and their salts, such as cholic acid, deoxycholic acid and sodium glycocholates, sodium caprate or sodium laurate, sodium oleate, sodium lauryl sulphate, sodium cetyl sulphate, sulfated castor oil and sodium dioctylsulfosuccinate, cocamidopropylbetaine and laurylbetaine, fatty alcohols, cholesterols, glycerol mono- or -distearate, glycerol mono- or - dioleate and glycerol mono- or -dipalmitate, and polyoxyethylene stearate.

[0034] Nonlimiting examples of sweetening agents useful in a composition described herein include sucrose, fructose, lactose, aspartame, saccharine, or sucralose. Nonlimiting examples of flavoring agents for use in a composition described herein include peppermint, oil of wintergreen or fruit flavors such as cherry or orange flavor. Nonlimiting examples of coating materials for use in a composition described herein include gelatin, wax, shellac, sugar or other biological degradable polymers. Nonlimiting examples of preservatives for use in a composition described herein include methyl or propylparabens, sorbic acid, chlorobutanol, phenol and thimerosal.

[0035] Additionally or alternatively, the present chromium compositions can be incorporated into food or beverages. Juices, energy drinks, diet drinks, protein bars, and the like can be used as a vehicle for oral delivery of the present chromium compositions.

Synthesis and characterization of chromium complexes and reference compounds.

[0036] Synthesis and characterization of chromium complexes disclosed herein is performed according to the methods disclosed in the examples below.

[0037] Chromium compounds are screened employing the following in vitro assays as compared to known chromium complexes: chromium nicotinate, chromium picolinate, chromium histidine, chromium triphenylalaine and chromium nicotinoglycinate: 1. Solubility analysis; 2. Insulin sensitivity and glucose metabolism / utilization assay; 3. Stability analysis (time, temperature and pH); 4. Cytotoxicity assay (lactate dehydrogenese leakage assessment); 5. Absorption study using the intestinal reperfusion model.

[0038] Expanded in vivo testing of the most promising compounds employing the following assays as compared to other chromium complexes: chromium nicotinate, chromium picolinate, chromium histidine, chromium triphenylalaine and chromium

nicotinoglycinate: 1. Bioavailability; 2. Glucose metabolism/uptake/utilization; 3. Insulin sensitivity; 4. Lipid metabolism (animal in vivo); 5. Acute toxicity (LD ₅₀ ).

Tryptophan-Chromium Complex Method I

[0039] The synthesis was made effective through an intermediate of tris-(ethylenediamine) chromium.

Synthesis of tris(ethylenediamine)chromium.

[0040] Zinc metal (Ig) was added to a solution of chromium(III) chloride (CrCl ₃ -OH ₂ O, 26.6 g, 0.11 mole) in methanol (5OmL). The mixture was refluxed at 70-80 ⁰ C. Anhydrous ethylenediamine (36 g, 0.6 mole) was added drop-wise to the refluxing chromium salt solution and the refluxing was continued for one hour. The solution was cooled, filtered and the yellow product, washed first with 10% ethylenediamine solution in methanol (75 mL) and then with ether. Finally the product was dried in air (yield 19 g).

Synthesis of tris(tryptohanato)chromium

[0041] Tris(ethylenediamine)chromium (0.6 g, 1.9 mmole) was added to a stirred suspension of hot L-tryptophan ( 2.0 g, 9.6 mmole) in water (30 mL). The mixture was heated at 80-90 ⁰ C refluxed further for 5 hour and the solid product obtained was filtered while hot. The solid was washed with hot water (200 mL) to remove the unreacted starting materials. The product was vacuum dried ( 0.8 g, 64 %). The Electrospray Ionization Mass Spectrum of the compound indicated the peak corresponding to the product.

Method II

[0042] A suspension of tryptophan (4.59 g, 22.5 mmol) in water (120 mL) was heated to 70-80 ⁰ C. A solution of chromium chloride (CrCl ₃ -OH ₂ O, 1.995 g, 7.5 mmol) in water (15 mL) was added to it and was maintained at this temperature under stirring for 7 h. The resulting mixture was cooled to room temperature, frozen at -80 ⁰ C and lyophilized. After lyophilizing for 48 h, the dark purple solid was washed with acetone and air dried to obtain the pure product. The product was subjected to elemental analysis: Calculated for Cr(TRP) ₃ .3HC1.2H ₂ O: C 49.11, H 5.00 N 10.41; Observed: C 49.84; H 5.18; N 10.41; Electro Spray Ionization Mass Spectrometry: Calculated for Cr(TRP) ₃ : 661; Observed a peak at 662.3 (M+l)

Tyrosine-Chromium Complex Method I

[0043] Due to poor solubility of Tyrosine, even in DMSO, the method I using Cr(en)3 complex did not work well, therefore the second method was adopted for the synthesis.

Method II

[0044] A suspension of tyrosine (8.145 g, 44.95 mmol) in water (350 mL) was heated to reflux. A solution of Chromium chloride (CrCl ₃₁ OH ₂ O, 2.66 g, 10 mmol) in DI water (35 mL) was added to it and was maintained refluxing overnight, under stirring. Cooled to room temperature, and filtered the purplish solution (containing lot of un-dis solved white material). The solution was frozen at -80 ⁰ C and lyophilized. After lyophilizing for 48 h, the dark purple solid was washed with acetone and finally dried in air to get the pure product. Elemental analysis: Calculated for Cr(TYR) ₃ .3HC1.7H ₂ O: C 39.16, H 5.72 N 5.07; Observed: C 39.59; H 5.12; N 4.33. Electro Spray Ionization Mass: Calculated for Cr(TYR) ₃ 592; Observed a peak at 593 (M+l).

5-Hvdroxytrvptophan Chromium Complex

[0045] A suspension of 5-Hydroxytryptophan (2.20 g, 10 mmol) in DI water (100 mL) was heated to 70-80 ⁰ C. A solution of Chromium chloride (CrCl ₃ .6H ₂ O, 0.88 g, 3.31 mmol) in DI water (20 mL) was added to it and was maintained at this temperature under stirring for 9 h. Cooled to room temperature, frozen at -80 ⁰ C and lyophilized. After lyophilizing for 48 h, the dark purple solid was washed with acetone and finally dried in air to get the pure product. Elemental analysis: Calculated for Cr(HTRP) ₃ .3HC1.2H ₂ O: C 46.35, H 4.72 N 9.83; Observed: C 46.17; H 4.84; N 9.53. Electro Spray Ionization Mass: Calculated for Cr(TYR) ₃ 709; Observed a peak at 710 (M+l).

Dinicotino Glutamino Chromium Complex

[0046] A suspension of nicotinic acid (3.60 g, 29.24 mmol) in DI water (120 mL) was heated to 70-80 ⁰ C. Glutamic acid (2.22 g, 15.1 mmol) was added to it and continued heating. Once the whole material was dissolved a solution of Chromium chloride (CrCl ₃ .6H ₂ O, 4.05 g, 15.2 mmol) in DI water (20 mL) was added to it. The mixture was stirred at 70-80 ⁰ C for 9h and cooled to room temperature, frozen at -80 ⁰ C and lyophilized. The dark solid obtained was collected and washed with acetone and dried to get the product.

Elemental analysis: Calculated for Cr(NIC) ₂ (GLU).3HC1.3H ₂ O: C 33.73, H 4.16 N 6.94; Observed: C 33.40; H 3.70; N 6.91

Dinicotino Aspartato Chromium Complex

[0047] A suspension of nicotinic acid (3.60 g, 29.24 mmol) in DI water (120 mL) was heated to 70-80 ⁰ C. Aspartic acid (1.99 g, 15.1 mmol) was added to it and continued heating. Once the whole material was dissolved a solution of Chromium chloride (CrCl ₃ .6H ₂ O, 4.05 g, 15.2 mmol) in DI water (20 mL) was added to it. The mixture was stirred at 70-80 ⁰ C for 9h and cooled to room temperature, frozen at -80 ⁰ C and lyophilized. The dark solid obtained was collected and washed with acetone and dried to get the product.

Evaluation of Chromium (III) Complexes as Disclosed Herein

[0048] Chromium complexes are evaluated for bioavailability and in vivo activity. Chromium tris(tryptophan), chromium tris(5-hydroxytryptophan), chromium dinicotinate glutamate, and chromium tris(cinnamate) were all evaluated using the following assays.

In Vivo Assessment: Obese Zucker rats are used as an ideal type II diabetic animal model for this evaluation. Each compound is tested at 200 μg elemental chromium (III) human equivalency dosage. The study is conducted and the following parameters are monitored: (1) Body weight; (2) Lean body mass; (3) Blood Pressure; (4) mean plasma glucose levels; (5) Lipid profile (total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL), and triglycerides (TG)); (6) Glycosylated hemoglobin (HbAIc); (7) Plasma lipid peroxidation and RBC lipid peroxidation; (8) Plasma TNFα; (9) Plasma C-reactive protein; (10) Serum ALT, BUN and CK levels; and (11) chromium (III) content in liver, pancreas, kidney, blood and skeletal muscle.

[0049] Numerous modifications and variations in the practice of the invention are expected to occur to those skilled in the art upon consideration of the presently preferred embodiments thereof. Consequently, the only limitations which should be placed upon the scope of the invention are those which appear in the appended claims.