Abstract:
A composition for inhibiting absorption of fat and cholesterol from the gut and a method for making and using the composition. The composition comprises β-sitosterol bound irreversibly to pectin to form a β-sitosterol/pectin complex.

Description:
This is a continuation of application Ser. No. 08/430,136, filed Apr. 26, 1995 (now abandoned) which is a continuation of application Ser. No. 08/083,340, filed Jun. 25, 1993 (now abandoned). 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a composition and method for the reduction of serum cholesterol and weight reduction. 
     BACKGROUND OF THE INVENTION 
     Cholesterol is an essential molecule in animals, required for the synthesis of cell membranes and as a precursor of steroid hormones and bile salts. However, high levels of serum cholesterol, especially low density lipoprotein (LDL), and serum lipids have been correlated with an increased risk of coronary heart disease. Deposition of lipid plaques on the intima of arteries (atheroma), resulting in atherosclerosis, appears to occur most readily when serum lipids are elevated in concentration. 
     The average diet in the United States provides about 40 percent of calories as lipids and approximately 57% of adult Americans have borderline high cholesterol (greater than 200 mg/dl). Coronary heart disease constitutes a leading cause of mortality and morbidity in the United States. Its principle underlying cause, atherosclerosis, is responsible for a large percentage of deaths and disabilities. 
     Dietary management is generally recommended to lower total and LDL cholesterol concentrations by reducing the intake of saturated fats and cholesterol and weight reduction for those overweight, by eliminating excess calories. However, many people at moderate to high risk for coronary heart disease are unwilling to change to a low risk diet or find that such a change is not feasible. As an alternative several medications and dietary supplements such as cholestyramine resin, probucol, colestipol HCl, nicotinic acid, mevinolin, pectin, guar gum and oat bran have been proposed for use to control serum cholesterol levels. However, for the most part these medications are unpleasant to take and may have undesirable side effects. Brans and fibers as dietary supplements must be taken in large volumes to be minimally effective. Even if these dietary supplements are effective in reducing serum cholesterol they will not affect weight reduction unless fat intake is limited. 
     Another naturally occurring compound reported to be effective in lowering serum cholesterol is a plant steroid, β-sitosterol. β-sitosterol has been shown to impair adsorption of cholesterol. However the compound can be absorbed and result in xanthomatous deposits and can have an estrogen like activity. 
     There is a need for a dietary supplement which lowers cholesterol, especially low density lipoprotein, by altering dietary fat and cholesterol absorption. Such a supplement should be palatable and non-toxic for extended use. 
     SUMMARY OF THE INVENTION 
     A composition for inhibiting absorption of fat and cholesterol from the gut is described. The composition comprises β-sitosterol bound irreversibly to pectin to form a β-sitosterol/pectin complex. 
     The β-sitosterol/pectin complex is prepared by a method comprising mixing β-sitosterol and pectin and suspending the β-sitosterol/pectin mixture in water. The suspension is then heated to complex β-sitosterol and pectin and then acidified. The acidified β-sitosterol/pectin is then heated to form a β-sitosterol/pectin complex. 
     The composition is useful for weight reduction when administered to a patient desiring a reduction in body weight and for reducing serum cholesterol levels in a patient suffering from elevated serum cholesterol. 
     DETAILED DESCRIPTION 
     The present invention relates to a complex of pectin and β-sitosterol. The compounds are each known to be effective in reducing cholesterol, however, to be effective they are required in large quantities. Also β-sitosterol has toxic or at least undesirable side effects. 
     β-sitosterol is derived from soy and rice and has a structure similar to cholesterol, except for the substitution of an ethyl group at C-24 of its side chain. Pectin is a polysaccharide derived primarily from citrus rind. It has a molecular weight of 20,000-40,000, of partial methyl ester of α-(1→4) linked D-galacturonate sequences interrupted with (1→2)-L-rhamnose residues. Neutral sugars, D-galactose, L-arabinose, D-xylose and L-fructose, form side chains of the pectin molecule. Pectin is not broken down by enzymes of the gastrointestinal tract and is, therefore, a dietary fiber. 
     For use in the present invention pectin is irreversibly complexed with β-sitosterol to form a complex which is not degraded by pH changes or enzymes of the gut, thus rendering the β-sitosterol non-absorbable by the gut. 
     To prepare the β-sitosterol/pectin complex, about 300 mg of β-sitosterol (Sigma Chemical Co. of St Louis Mo., Cat. No. S9889) is mixed with about 30 mg pectin (Sigma Chemical Co., Cat. No. P2157) the mixture is dried at room temperature for about five minutes. About 30 ml of distilled water is added to the mixture and the suspension is stirred at room temperature for about 5 minutes to hydrate the β-sitosterol and pectin. The suspension is then heated at about 93° C. for about 2 minutes to complex the β-sitosterol with the pectin. The complexed suspension is then cooled at room temperature for about 5 minutes and acidified by the addition of about 15 ml of rice wine vinegar (4.3% v/v acetic acid). The acidified complex is stirred at room temperature for about 5 minutes, heated at about 93° C. for about 6 minutes and then sized by pushing the acidified suspension through a 20 mesh sieve. 
     Excipients are then added. About 335 mg of calcium carbonate and about 2 ml of water are added and the mixture stirred at about 40° C. for about 10 minutes. About 18 mg of calcium silicate, about 18 mg of silicon dioxide and about 18 mg of croscarmellose sodium are then added and the mixture is stirred at about 40° C. for about 10 minutes. About 10 mg of magnesium stearate is then added and the mixture is stirred for about 5 minutes. The mixture is pressed into about a 700 mg tablet with about 20,000 psi pressure. 
     One tablet of about 700 mg is taken about 30 minutes before a meal. 
    
    
     EXAMPLE 1 
     300 mg of β-sitosterol was mixed with 30 mg pectin and dried at room temperature for five minutes. 30 ml of distilled water was added to the mixture and the resultant suspension was stirred at room temperature for 5 minutes to hydrate the β-sitosterol and pectin. The suspension was then heated at 93° C. for 2 minutes to complex the β-sitosterol with the pectin. The complexed suspension was cooled at room temperature for 5 minutes and acidified by the addition of 15 ml of rice wine vinegar. The acidified complex was stirred at room temperature for 5 minutes, heated at 93° C. for 6 minutes and sized by pushing the β-sitosterol/pectin complex through a 20 mesh sieve. 
     334 mg of calcium carbonate and 2 ml of water were added and the mixture was stirred at 40° C. for 10 minutes. 18 mg of calcium silicate, 18 mg of silicon dioxide and 18 mg of croscarmellose sodium were then added and the mixture was stirred at 40° C. for 10 minutes. 10 mg of magnesium stearate was then added and the mixture was stirred for an additional 5 minutes. The resultant mixture was pressed into 727 mg tablet with 20,000 psi pressure. 
     The resultant pill was placed in distilled water, pH 7, and broke down to a soft, whitish, pleasant smelling flocculent within 30 minutes. 
     EXAMPLE 2 
     Pills prepared as described in Example 1 were crushed and suspended in 100 ml of distilled water, adjusted to pH 3 with acetic acid. The suspension was heated at 36° C. for 30 minutes with vigorous agitation. The suspension was then cooled for 5 minutes and a suspension sample was collected. The remaining suspension was filtered through 100 micron filter paper and the filtrate collected. The suspension sample and the filtrate were analyzed by infrared Fourier resonance spectroscopy (IFRS). Samples were also dried and the residue weight determined. Solutions of β-sitosterol alone, pectin alone and an uncomplexed mixture of β-sitosterol and pectin where used for comparison in the IFRS analysis. 
     The dry weight of the β-sitosterol/pectin complex and the filtrate indicated that less than 1% w/w of the complex was solubilized by the solubilization conditions at pH 3. The IFRS analysis indicated that the β-sitosterol/pectin complex retained double and single carbon-carbon bonds different from either β-sitosterol and pectin. 
     The pH of the stomach is normally about pH 3, therefore, the β-sitosterol/pectin complex retains its structure and is expected to pass through the stomach intact. 
     EXAMPLE 3 
     Pills prepared as described in Example 1 were crushed and suspended in 100 ml of distilled water, adjusted to pH 11 with sodium hydroxide. The suspension was heated at 36° C. for 60 minutes with vigorous agitation. The suspension was cooled for 5 minutes and a suspension sample was collected. The remaining suspension was filtered through 100 micron filter paper and the filtrate collected. The suspension sample and the filtrate were analyzed by IFRS. Samples were also dried and the residue weight determined. Solutions of β-sitosterol alone, pectin alone and an uncomplexed mixture of β-sitosterol and pectin where used for comparison in the IFRS analysis. 
     The dry weight of the β-sitosterol/pectin complex and the filtrate indicated that about 50% w/w of the β-sitosterol/pectin complex was solubilized by the solubilization conditions at pH 11. The IFRS analysis indicated that the β-sitosterol/pectin complex retained double and single carbon-carbon bonds different from either β-sitosterol and pectin. 
     The pH of the distal small intestine is about pH 11. Therefore, the β-sitosterol/pectin complex is expected to be solubilized in the small intestine where it will be available for complexing cholesterol and fat receptors. 
     EXAMPLE 4 
     Five patients were given a 727 mg tablet, prepared as described in Example 1, about 30 minutes before each meal for two weeks. At the end of the two week period serum samples were obtained and analyzed for β-sitosterol by gas chromatography as described by Vanhanen et al., Circulation Supplement II, 2390, (1991), incorporated herein by reference. 
     No β-sitosterol was detected in the samples, indicating that β-sitosterol was not absorbed from the gut and remains complexed to the pectin. 
     EXAMPLE 5 
     Fourteen patients with mixed lipoproteinemia, on a diet of 500 mg of cholesterol/day, were given a 727 mg tablet of β-sitosterol/pectin complex, prepared as described in Example 1, about 30 minutes before each meal for eight weeks in a double blind, cross-over study. Total cholesterol, LDL and HDL were performed prior to beginning the administration of the β-sitosterol/pectin complex and at monthly intervals thereafter, were determined enzymatically in an enzyme linked assay using cholesterol esterase, cholesterol oxidase and peroxidase, by methods well known to those skilled in the art and as described in Sigma procedure No. 352 (Sigma Chemical Co., St Louis Mo.), incorporated herein by reference. Body weight was also determined. The results are set out in Tables I-IV. 
     
                       TABLE I______________________________________TOTAL CHOLESTEROL&#34;Normal&#34; =    Pre-     1 Month    2 Months                               3 Months100-200.sup.1    Admin.   Admin.     Admin. Admin.______________________________________Average  277      231        241    241Range    192-352______________________________________ .sup.1 mg/dl 
    
     After administration for 1 month a reduction of 16.4% was observed in the serum cholesterol of the patients in the study. A statistically significant reduction was maintained over three months. 
     
                       TABLE II______________________________________LDL CHOLESTEROL&#34;Normal&#34; =    Pre-     1 Month    2 Months                               4 Months&gt; 130.sup.1    Admin.   Admin.     Admin. Admin.______________________________________Average  223      157        175    156.sup.2Range    120-252  118-218    128-224______________________________________ .sup.1 mg/dl .sup.2 results for 2 patients whose LDL cholesterol began at 389 mg/dl 
    
     A decrease of 15.2% was observed in LDL cholesterol levels of the patients in the study at 1 month and a statistically significant decrease was maintained over 4 months. 
     
                       TABLE III______________________________________HDL RATIOS      Pre-    1 Month    2 Months                                4 Months&#34;Normal&#34; = Admin.  Admin.     Admin. Admin.______________________________________Average    6.8     6.8        6.7    7.6.sup.1______________________________________ .sup.1 for 3 patients 
    
     No significant difference was observed in the HDL ratio. 
     
                       TABLE IV______________________________________BODY WEIGHT                        2 MonthsPre-Admin.       1 Month Admin.                        Admin.______________________________________Average 82.1.sup.1   86.6        76.2Range   57.2-113.9   68.5-100.2  57.2-78______________________________________ .sup.1 kg 
    
     A body weight increase of 5.5% was observed after one month of administration of the β-sitosterol/pectin complex. However, after two months administration there was a decrease of 7.2% from the pre-administration average weight. 
     The patients in the study were also monitored for liver and kidney function and interference of the β-sitosterol/pectin complex with current medication. No change, during the course of the study, was attributed to the administration of the complex. Additionally, no adverse reactions such as nausea, vomiting, diarrhea, constipation, skin rash, headache, etc. were suffered by the patients during the period they were taking the β-sitosterol/pectin complex. 
     Therefore, the β-sitosterol/pectin complex is effective in reducing total cholesterol and LDL cholesterol. The β-sitosterol/pectin complex is also effective in body weight reduction. 
     EXAMPLE 6 
     Fat was tagged with retinoic acid and given to a patient with a measured meal, as described in See et al., Clinical Research (April, 1991) incorporated herein by reference. A second patient was given ox bile (cholic acid) in addition to the tagged fat and a third patient was given β-sitosterol/pectin complex prepared as described in Example 1, in addition to tagged fat, 30 minutes prior to the ingestion of the meal. The serum levels of the retinoic acid tag were determined for each patient at two hourly intervals. The results are summarized in Table V. 
     
                       TABLE V______________________________________Retinoic Acid Absorption        0   2 hr.      4 hr.  6 hr.______________________________________Tagged Fat      45.sup.1                62         67   52Tagged fat + ox bile          52    55         78   77Tagged fat +   38    47         43   42β-sitosterol/pectin______________________________________ .sup.1 μg/dl retinoic acid 
    
     The results indicate that tagged fat is taken up and reaches a maximum in 2-4 hours after ingestion. By 6 hours the serum levels have dropped to about baseline. The addition of ox bile results in a greater increase in fat absorption and serum fat levels which remain at an elevated level after 6 hours. In contrast β-sitosterol/pectin complex results in a lower absorption of the retinoic acid tag, about half the amount absorbed when tagged fat was given alone, after two hours. By 4 hours the fat absorption had dropped to baseline indicating that β-sitosterol/pectin complex inhibits dietary fat absorption. 
     The present invention is not limited to the specific embodiment given. It will be obvious to one skilled in the art that other doses and timing of the dosage could be used to advantage to suit the needs of different individuals and that other excipients could be used. Therefore, the present invention is not intended to be limited to the working embodiments described above. The scope of the invention is defined in the following claims.