Composition comprising cinnamon extract

Abstract

The invention concerns a composition for lowering the glycemic index comprising, or consisting of an alcoholic extract of cinnamon in an amount of at least 10% by weight compared to the total weight of the composition, and optionally a carrier, a food composition comprising a composition for lowering the glycemic index in an amount ranging from 0.1% to 5% by weight compared to the total weight of the food composition, the use of a composition for lowering the glycemic index or of a food composition as a glycemic index lowering agent.

Claims

1. A method for reducing glycemic index of food, said method comprising adding to said food an extract of cinnamomum zeylanicum, obtained by the process comprising the following steps: a) contacting dried milled cinnamomum zeylanicum bark with an alcohol based extraction solvent at a temperature of around 50° C.; b) filtering out the solids and collecting alcoholic extract; c) washing said solids by stirring with an alcohol based extraction solvent; d) filtering out the solids and collecting alcoholic extract; e) combining said alcoholic extracts; f) removing non-soluble residues by decantation, filtration, centrifugation or a combination thereof; g) evaporating the solvents from the combination at a temperature inferior or equal to 50° C.; and h) recovering a dry extract, wherein the extract of cinnamomum zeylanicum comprises at least 25% by weight polyphenols, and wherein the food comprises starch and the weight ratio cinnamon extract/starch is of 1/30 or more.

2. The method for reducing glycemic index of food according to claim 1, said method comprising adding said extract to the food comprising starch, wherein the weight ratio extract/starch is 1/500 or more, 1/1000 or more or 1/10000 or more.

3. The method according to claim 1, wherein the alcohol based extraction solvent further comprises water and the weight ratio water/alcoholic solvent ranges from 5/95 to 50/50.

4. The method according to claim 1, wherein the alcohol based extraction solvent further comprises water and the weight ratio water/alcoholic solvent is 50/50.

5. The method according to claim 1, wherein the alcohol based solvent is chosen from methanol, ethanol, n-propanol, iso-propanol, 2-butanol, and combination thereof.

6. The method according to claim 5, wherein the solvent is ethanol.

7. The method according to claim 6, wherein the solvent further comprises water and the weight ratio water/ethanol is 50/50.

8. The method according to claim 1, wherein steps a) and b) are repeated using said solvent extract obtained in step b) and a new batch of dried cinnamomum zeylanicum.

9. The method according to claim 1, wherein steps a) and b) are repeated using said solvent extract obtained in step b) in successive batches of dried cinnamomum zeylanicum to obtain saturation of the solvent with the extract.

10. The method according to claim 1, wherein step a) is performed for 1 to 5 hours.

11. The method according to claim 10, wherein step a) is performed for at least 2 hours.

12. A method for producing a food product with a reduced glycemic index, said method comprising reducing the glycemic index of food with the method of claim 1 and recovering said food product.

Description

(1) FIG. 1 shows the effect of the cinnamon extract on the glycemic index of starch.

(2) FIG. 2 shows the effect of ethanol and water cinnamon extracts on the the glycemic index of starch.

(3) FIG. 3 exhibits the effect of cinnamon extract and amount of starch ingested on the glycemic index of starch.

(4) FIG. 4 shows the effect of the cinnamon extract on the glycemic index of starch and on glucose.

(5) FIG. 5 presents the effect of the cinnamon extract on the insulinic response to starch.

(6) FIG. 6 exhibits the effect of the cinnamon extract on digestion enzymes: alpha-glucosidase, alpha-amylase, and lipase.

(7) FIG. 7 demonstrates that using high temperature during the process reduces the effect of the cinnamon extract on digestion enzymes and on glycemic response to starch.

(8) FIG. 8 presents the effect of the cinnamon extract incorporated in food matrixes.

EXAMPLES

Example 1: Preparation of a Cinnamon Extract

(9) The cinnamon extract was prepared according to the following steps: contacting dried milled cinnamon cinnamomum zeylanicum bark with 10 times their weight of a 1/1 weight ratio ethanol-water mixture and agitating for 2 hours at a temperature of 50° C., the solids are filtered out and the alcoholic extract is collected, the remaining wet solids are washed by stirring with a 1/1 weight ratio ethanol-water mixture, with a volume corresponding to 10 times the weight of the dry solids, for 30 minutes, the solid are filtered out and the alcoholic extract collected, the extraction solutions are combined and left for decantation or filtered to remove non-soluble residues, the water and ethanol are evaporated under vacuum, leading to a brown syrup, the concentrate is then frozen for lyophilisation, and the dry cinnamon extract is recovered.

(10) The cinnamon extract is named Alpha-401.

Example 2: Preparation of a Cinnamon Extract

(11) The cinnamon extract was prepared according to the following steps: contacting dried milled cinnamon cinnamomum zeylanicum bark with 7 times their weight of a 1/1 volume ratio ethanol-water mixture and agitating for 2 hours at a temperature of 50° C., the solids are filtered out and the alcoholic extract is collected, the remaining wet solids are washed by stirring with a 1/1 volume ratio ethanol-water mixture, with a volume corresponding to minimum of 2 times the weight of the dry solids, for a minimum of 30 minutes, the solid are filtered out and the alcoholic extract collected, the extraction solutions are combined and left for decantation or filtered to remove non-soluble residues, the water and ethanol are evaporated under vacuum, leading to a brown syrup, the concentrate is then frozen for lyophilisation or using a vacuum oven at 50° C., and the dry cinnamon extract is recovered.

(12) The cinnamon extract is named Alpha-401.

Example 3: Dose Effect in Rats

(13) Six-week old Wistar rats (Janvier Laboratories, France) weighing around 250 g were used for the experiment. One day before the test, rats were randomly assigned to the different experimental groups (8 animals per group) according to their body weight values.

(14) Starch tolerance test (STT) was performed by the administration by oral gavage of a 7.5% purified wheat starch solution at 1.5 g/kg or 20 ml/kg of body weight. The actual volume administered to each rat was calculated and adjusted based on the most recent body weight of each animal.

(15) STT onset was between 12 h00 and 13 h00 on animals fasted overnight. Blood samples (one drop) were collected via the tail vein for glucose determination using a hand-held glucometer (OneTouch Ultra 2, LifeScan) before and 15, 30, 60, and 120 min after starch administration.

(16) In this experiment, the effect of starch alone and starch containing escalating doses of an alcoholic extract of cinnamomum zeylanicum (named Alpha-401): 6.25, 12.5, 25, 50, and 100 mg/kg of body weight were compared.

(17) The FIG. 1 represents mean values+/− standard error of the mean (sem; n=8) and shows that the alcoholic extract of cinnamomum zeylanicum reduced the glycemic index of starch in a dose-dependent manner. On the graph representing the area under the curve (AUC) between 0 and 120 min, this effect is significant from 12.5 mg/kg of body weight (t-test p<0.05).

Example 4: Comparison with Aqueous Extracts

(18) The protocol was the same than Example 2.

(19) In this experiment the effect of alcoholic and aqueous cinnamon extracts mixed to starch at the dose of 50 mg/kg of body weight were compared. The aqueous extracts are commercial extracts.

(20) The FIG. 2 shows that two different aqueous extracts presented no effect on the glycemic index of starch. In the same conditions, the alcoholic extract named Alpha-401 (from Example 1) significantly reduced the peak of glycemia at 15 and 30 min (t-test p<0.001 and p<0.05, respectively) and the AUC between 0 and 120 min (t-test p<0.05). This shows the extract according to the invention is having an effect on glycemic index of starch, whereas a water extract has no effect on glycemic index of starch.

Example 5: Effect Dependant of the Quantity of Starch

(21) The protocol was the same than for Example 2 at the difference that 3 different quantities of starch were given to the rats: 1.5, 1, and 0.5 g/kg of body weight.

(22) Then, the effect of an alcoholic extract of cinnamomum zeylanicum (named Alpha-401) given at the dose of 50 mg/kg of body weight on the glycemia induced by the digestion of different amount of starch were compared.

(23) The FIG. 3 shows that an alcoholic extract of cinnamomum zeylanicum decreased the glycemic index of 1.5 g/kg of body weight of starch in normal rats but when the amount of starch is reduced to 1 or 0.5 mg/kg of body weight this effect is lost. Thus, the effect of cinnamon extract on the glycemic index of starch is depending on the quantity of ingested starch.

Example 6: Specific Effect on Starch Versus Glucose

(24) The protocol was the same than for Example 2, at the difference that starch or glucose were given to the animals. Then, the effect of an alcoholic extract of cinnamomum zeylanicum (named Alpha-401) given at the dose of 50 and 100 mg/kg of body weight on the glycemia induced by the ingestion of starch and glucose were compared.

(25) The FIG. 4 shows that an alcoholic extract of cinnamomum zeylanicum decreased the glycemic index of starch in a dose-dependent manner whereas, in the same conditions, it presented no effect on the glycemia induced by the ingestion of pure glucose (glucose tolerance). This example suggests that the main effect of cinnamon extract is done through a reduction of starch digestion.

Example 7: Effect of the Cinnamon Extract (Alpha-401) on the Insulinic Response to Starch in Rats

(26) The protocol was the same than Example 2, at the difference that only the dose at 50 mg/kg was tested and blood samples were connected to measure insulin levels using an ELISA kit (Ultrasensitive Mouse Insulin ELISA, Mercodia).

(27) The FIG. 5 shows that the cinnamon extract Alpha-401 significantly reduced the glycemic response to starch but also reduced the insulinic response to starch. Then, this extract reduced glycemic index of starch without stimulating insulin secretion. On the contrary, the cinnamon extract put the pancreas at rest.

Example 8: Effect of the Cinnamon Extract (Alpha-401) on Digestion Enzymes

(28) Alpha-glucosidase activity was assayed as follow: 50 μL of the solutions to be tested containing the inhibitors or distilled water (used as control) were added to 100 μL of the enzymatic solution consisting of 1 U/mL of Saccharomyces cerevisiae alpha-glucosidase (Sigma-Aldrich) in 50 mM phosphate buffer saline at pH6.9 and pre-incubated during 10 min at room temperature. 50 μL of substrate solution, consisting of 5 mM p-nitrophenyl-alpha-D-glucopyranoside (PNP-G; Sigma-Aldrich) in 50 mM phosphate buffer saline at pH6.9, was added and the mixture was incubated during 5 min at room temperature. The reaction was stopped by the addition of a solution of sodium carbonate 100 mM and the absorbance read at 405 nm. The assay was run in triplicates. The anti-diabetic drug acarbose was used as positive control.

(29) The FIG. 6 shows that the cinnamon extract Alpha-401 inhibits alpha-glucosidase activity with an IC50 of 10 μg/mL.

(30) Alpha-amylase activity was assayed using the Enzymatic assay of alpha-amylase inhibitor (Sigma-Aldrich) using alpha-amylase from porcine pancreas and starch from potato. The assay was run in triplicates. The anti-diabetic drug acarbose was used as positive control.

(31) The FIG. 6 shows that the cinnamon extract Alpha-401 inhibits alpha-amylase activity with an IC50 of 23 μg/mL.

(32) Lipase activity was assayed as follow: 25 μL of the solutions to be tested containing the inhibitors or distilled water (used as control) were added to 25 μL of the enzymatic solution consisting of 1 mg/mL of lipase from porcine pancreas (Sigma-Aldrich) in distilled water and pre-incubated during 5 min at room temperature. 50 μL of substrate solution, consisting of 0.1 mM 4-Methylumbelliferyl oleate (MUO; Sigma-Aldrich) in Dulbecco's phosphate buffer saline, was added and the mixture was incubated during 20 min at room temperature. The reaction was stopped by the addition of a solution of sodium citrate 100 mM and the luminofluorescence was read at 320 nm stimulation and 450 nm emission wavelengths. The assay was run in triplicates.

(33) The FIG. 6 shows that the cinnamon extract Alpha-401 inhibits lipase activity with an IC50 of 44 μg/mL.

Example 9: Importance of the Temperature Used During the Extraction Process on the Efficacy of the Cinnamon Extracts

(34) The protocols were the same than for Example 2 for starch tolerance test and than for Example 7 for the alpha-glucosidase test.

(35) Sample Alpha-401 50° C. and Alpha-401 60° C. were dried at 50 and 60° C., respectively, during the extraction process.

(36) The FIG. 7 shows that an extraction process using excessive temperature abolishes in vivo the effect of cinnamon extract on the reduction of glycemic response to starch and reduces in vitro the inhibition effect of cinnamon extract on alpha-glucosidase activity. This example demonstrates that high temperatures during the extraction process reduce the efficacy of cinnamon extract on starch glycemic index.

Example 10: Effect of the Cinnamon Extract (Alpha-401) Incorporated in Food Matrixes on the Glycemic Response in Rats

(37) The protocol was the same than Example 2, at the difference that the cinnamon extract was incorporated in food matrixes at different levels (0.5 to 2%). The formulated foods were then put in suspension to be given to the rats.

(38) For the bakery applications, breads were made by a baker following the regular process of confectioning and cooking but by incorporating in the pastry different amounts of cinnamon extract. Then, suspensions of bread were given to the rat at the dose of 1.6 g of bread/kg of body weight. The FIG. 8 shows that the cinnamon extract dose-dependently reduced the glycemic index of bread. This effect is already significant at an incorporation rate of 0.5%.

(39) For pet food applications, a dog food diet was supplemented with 2% of the cinnamon extract Alpha-401, put in suspension and given to rats at 3 g of dog food/kg of body weight. The FIG. 8 demonstrates that the cinnamon extract reduced the glycemic response to a pet food diet.