MX2008005999A - Method of purifying episesamin - Google Patents

Abstract

A method of purifying episesamin capable of obtaining an episesamin-rich composition having a high content of episesamin by bringing a mixture of sesamins containing sesamin, episesamin and the like into contact with an aqueous medium thereby to obtain a slurry mixture and then separating asolid matter from the resulting mixture or dissolving the mixture of sesamins by heating in an appropriate aqueous medium and carrying out recrystallization by gradually cooling the resulting solution is disclosed. According to the invention, episesamin can be simply and efficiently purified from a mixture of sesamins containing mainly sesamin and episesamin.

Description

METHOD TO REFINE EPISESAMINE TECHNICAL FIELD This invention relates to a method for refining episesamin from a mixture of sesamin components.

PREVIOUS TECHNIQUE Various types of sesame lignan are found in sesame seeds and are known to usually contain not only sesamin in about 0.1-0.5% by weight, but also sesamol, sesamolin, sesaminol and the like. Unrefined sesame oil expressed from sesame seeds contains approximately 0.5-1.0% by weight of sesamin as a sesame lignan. It is also known that when sesame seeds are treated with mineral acids such as sulfuric acid, activated clay, or the like, sesamin compounds are formed, including not only sesamin but also episesamin which is an optically converted sesamin product and which inherent is not present in sesame seeds (non-patent reference 1 and non-patent reference 2). Such sesame lignans mainly comprise components of sesamin which are known to have various physiological activities including, example, the action of inhibiting A5-unsaturation enzymes, antioxidant action against lipids, antihypertensive action, the action of improving liver functions, the action of purifying active oxygen, action of reducing cholesterol, and the action of preventing disease derived from drinking and, therefore, they are expected to prove useful as a healthy food. As a method by which products containing sesamin components at high concentrations can be separated from sesame seeds, it has been proposed to press sesame seeds, subject the thought seeds to extraction with an organic solvent, and perform molecular distillation in the extract. Specific examples include: (1) distilling sesame oil with steam under reduced pressure and subjecting the distillate to molecular distillation (see patent reference 1); (2) distilling sesame oil with steam under reduced pressure, carrying out esterification reaction and / or ester exchange reaction in the distillate, and subjecting the reaction product to molecular distillation (see patent reference 2); (3) distilling sesame oil with steam, mixing the distillate with an aqueous solvent, and performing crystallization in the mixed system in the presence of an alkali (see patent reference 3); (4) distill sesame oil with steam under reduced pressure, mix the distillate with an aqueous ethanol solution containing at least 40% by weight of ethanol, separate the solution fraction from the mixed system, and add an alkali to the fraction of solution for crystallization (see patent reference 3); (5) distill sesame oil with steam under reduced pressure, mix the distillate with an ethanol solution aqueous containing at least 40% by weight of ethanol, separating the solution fraction from the mixed system, performing adsorption treatment in the separated solution fraction with an adsorbent, and performing desorption / elution from the adsorbent (see patent reference 4). ); and similar. It has also been described that the molecular distillation, crystallization or desorption / elution performed in (1) - (5) above can be followed even by recrystallization treatment to increase the concentrations of sesamin components (where the term is defined as "sesamin components" comprises sesamin, episesamin and sesamolin) (patent references 1-2). Recent studies on the differences between the physiological activities of sesamin and episesamine have revealed the superiority of the episesamin with respect to sesamin, as exemplified by higher transfer to the organs, improved gene expression of ß-oxidation enzymes in the liver, and marked improvement of the enzymatic activity (non-patent reference 3 and non-patent reference 4). [Patent reference 1] the official gazette of JP 7-25764 B. [Patent reference 2] the official gazette of JP 2003-183172 A. [Patent reference 3] the official gazette of JP 10-7676 A. [Reference of patent 4] the official gazette of JP 6-89353 B. [Reference of no patent 1] Namiki et al., "Goma - - Sounded Kagaku to Kinousei (Sesame - Its science and functions)", Maruzen Planet Co., Ltd (1998).

[Non-patent reference 2] Fukuda, Y. et al., J. Am. Oil Chem. Soc, 63, 1027-1031 (1986). [Non-Patent Reference 3] Sawada, R. et al., Lipids, 34, 633 (1999). [Non-patent reference 4] Kushiro, M. et al., J. Nutr. Biochem., 1 3, 289-295 (2002).

BRIEF DESCRIPTION OF THE INVENTION Problems to be solved by the invention As described above, various methods have been proposed as techniques by which products containing sesamin components at high concentrations can be separated from sesame oil; however, in order to retinal episesamin from a mixture of sesamin components, in particular, a mixture containing sesamin and episesamin, very few methods including isolation by column chromatography have been available, but such methods involve complicated operations and, what is more, they produce small amounts of the composition while presenting only a low efficiency. It is an object of the present invention to provide a method by which episesamine having high in vivo activity can be efficiently refined from the mixture of sesamin components.

Means for solving the problems As a result of intensive studies carried out in order to achieve the aforementioned object, the present inventors found that the components of sesamin, ie sesamin, episesamin and diasesamin, had different solubilities in aqueous media, i.e., water , water-soluble media, or aqueous solutions of said media. Then, the present inventors contacted the aqueous medium with a mixture of sesamin components that was in a solid state or at least part of which was in a dissolved state, thus forming a slurry, and then separated the solids from the mixture to produce an enriched episesamin composition with an increased relative episesamin content. Specifically, the mixture of sesamin components containing sesamin, episesamine and diasesamine was dissolved in the aqueous medium under heating and then the solution was slowly cooled to recrystallize, thus allowing the production of an enriched episesamin composition with an increased relative episesamin content. . The present inventors further found that when the concentration of episesamin in the mixture of sesamin components before recrystallization was greater than about 50% by weight, in particular, by 64% by weight and above, the relative content of episesamin in the Crystal formed by recrystallization was markedly increased; this discovery has led to the realization of the present invention.

Therefore, the present invention relates to the following methods for refining episesamin. 1 . A method for refining episesamine comprising contacting with an aqueous medium a mixture of sesamin components which is in a solid state or at least part of which is in a dissolved state, thereby forming a slurry, and then separating the solids of the mixture or carry out recrystallization with an aqueous medium, thus producing an enriched composition of episesamine with an increased relative episesamin content. 2. The method for refining episesamine as described in 1 above, wherein the mixture of sesamin components to be refined is a mixture of sesamin components containing at least sesamin and episesamin. 3. The method for refining episesamine as described in 2 above, wherein the enriched episesamin composition has an episesamin concentration greater than 55% by weight, preferably at least 70% by weight, based on the total weight of sesamin and episesamin. 4. The method for refining episesamine as described in any of 1-3 above, wherein the aqueous medium is water, a water-soluble medium or an aqueous solution of a water-soluble medium. 5. The method for refining episesamine as described in 4 above, wherein the aqueous medium is water, an alcohol, or an aqueous alcohol solution. 6. The method for retinating episesamine as described in above, wherein the aqueous medium is ethanol or an aqueous ethanol solution. 7. The method for retinating episesamine as described in any of 1-6 above, including recrystallizing the mixture of sesamin components with the aqueous medium to produce the enriched episesamin composition. 8. The method for retinating episesamine as described in any of 1-7 above, wherein the mixture of sesamin components with an improved episesamin concentration has been produced by the following steps: (1) dissolving the mixture of sesamin components in an oil or fat under heating; and (2) selectively crystallizing episesamine by means of a recrystallization technique to produce a composition containing episesamin with an improved episesamin concentration. 9. The method for retinating episesamine as described in 8 above, wherein the content of episesamin in the mixture of sesamin components is at least 64% by weight. 10. The method for retinating episesamine as described in 8 or 9 above, wherein the oil or fat having the mixture of sesamin components dissolved therein is subjected to treatment with an acid catalyst. eleven . The method for retinating episesamine as described in any of 1-7 above, wherein the mixture of sesamin components with an improved episesamin concentration has been produced by means of the following steps: (1) perform molecular distillation in a mixture that contains sesamin components that has been refined from sesame oil, thus giving a fraction in which the sesamin components are enriched; and (2) dissolving the fraction in water, a water-soluble solvent or a mixture thereof, optionally adding an alkali, and then precipitating the sesamin components to produce a sesamin / episesamin mixture with an improved episesamin concentration. . 12. The method for retinating episesamine as described in 1 1 above, wherein the enriched episesamin composition has an episesamin concentration greater than 55% by weight, preferably at least 70% by weight, based on the total weight of the sesamin and episesamin.

EFFECTS OF THE INVENTION In accordance with the method of the present invention for retinating episesamine, a mixture of sesamin-like components in structure, ie, a mixture of episesamin and a! less a selected component of sesamin and diasesamin can be treated to produce an enriched episesamin composition with an episesamin content improved relative, specifically one containing episesamine at a concentration greater than 55% by weight.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a CLAR diagram for the samples of the examples. Figure 2 is a graph showing how the concentration of episesamine (% by weight) that was attributed to the mixture of sesamin components varied in the samples of the examples before and after recrystallization. The mixture having an episesamine concentration before recrystallization as gratified on the horizontal axis was recrystallized to provide a final episesamin concentration (as plotted on the vertical axis). Figure 3 is a graph showing how the concentration of episesamine (% by weight) that was attributed to the mixture of sesamin components waned when the recrystallization was carried out with water, ethanol or an aqueous ethanol solution (ethanol v / v) used as an aqueous medium. Figure 4 is a graph showing how the concentration of episesamin (% by weight) that was attributed to the mixture of sesamin components varied when the recrystallization was carried out with water, ethanol or an aqueous ethanol solution (ethanol v / v) used as an aqueous medium.

Figure 5 is a graph showing how the concentration of episesamin (% by weight) that was attributed to the mixture of sesamin components varied when the recrystallization was carried out with an aqueous ethanol solution (ethanol v / v), a solution of aqueous ethanol + HCl (1 N) or a solution of aqueous ethanol + NaOH (1 N) used as an aqueous medium. Figure 6 is a graph showing how the episesamin concentration (% by weight) that was attributed to the mixture of sesamin components varied when cooling during recrystallization was performed at 20 ° C, 4 ° C or -20 ° C.

PREFERRED MODALITIES OF THE INVENTION Mixing of sesamin components As used herein, the mixture of sesamin components means episesamin containing lignan compounds or an extract comprising mainly such lignan compounds. The mixture of sesamin components to be refined usually contains not only episesamin but also lignan compounds such as sesamin and diasaminase, as well as impurities such as water. The refining method of the present invention can be applied to mixtures of sesamin components that are prepared by conventional known methods. Examples include: the method as described in the official gazette of Japanese Patent No. 3001589, which comprises adding an organic solvent to sesame oil treated with activated clay, leaving the mixture to stand, then completely separating the filtrate or the overlying liquid, and completely distilling the organic solvent to produce lignan compounds (a mixture of sesamin compounds); he. method as described in the official gazette of Japanese Patent No. 3205315, which comprises adding an aqueous ethanol solution for foaming as a by-product to the sesame oil production process (the distillate from the deodorizing step), letting the mixture stand overnight so that the soluble fraction of solvent is completely separated in layer, and precipitate lignan compounds (a mixture of sesamin components) in the presence of an alkali; the method as described in the official gazette of JP 2003-192562 A, which comprises deoxidizing sesame oil extracted from sesame seeds by pressing, then deodorizing and decolorizing deoxidized sesame oil with activated clay, distilling the sesame oil thus treated with steam under reduced pressure, mixing the distillate with an aqueous solvent, and carrying out precipitation in the mixed system in the presence of an alkali to produce a composition containing sesamin components at high concentrations; the composition containing sesamin components at high concentrations can optionally be dissolved in ethanol and subjected to recrystallization to produce a mixture of sesamin components; Although any of these methods can be used, the present invention is not limited in any way to mixtures of sesamin components that are prepared by those methods. The present inventors have already discovered that the episesamin can be crystallized selectively by dissolving the sesamin-containing composition in MCT (medium chain fatty acid triglyceride), then treating the solution with an acid catalyst such as activated clay, and adding crystals of episesamin seed to the filtered material (PCT / JP 2006/319493). The refining method of the present investment can, of course, be applied to this recrystallization product from MCT which is obtained by means of selective crystallization of episesamine.

Refining Method The present invention begins with placing the mixture of sesamin components to be refined in contact with an aqueous medium. After placing the mixture of sesamin components in contact with an aqueous medium, the episesamine can be refined by 1) a contact technique or 2) a recrystallization technique.

Aqueous medium The aqueous medium to be contacted in 1) or 2) above can be any medium that dissolves sesamin and episesamin in different degrees and can be exemplified by water; alcoholic solvents such as methanol, ethanol, and propanol; acetone; ethyl acetate; ether-containing solvents such as diethyl ether; and aqueous solutions thereof. One or more of these media can be used but ethanol is preferably used for various reasons such as low toxicity, a relatively low boiling point to allow easy removal after extraction, and easy availability. If ethanol or an aqueous ethanol solution is used as a solvent, they can remain in the enriched episesamin composition without harming humans and, therefore, the enriched refined episesamin composition can be used favorably as a composition for food. If an aqueous ethanol solution is used as a solvent, in order to increase the extraction efficiency and reduce the proportion of impurities, ie, increase the purity of the resulting episesamine enriched composition (its episesamine concentration), it is preferred to use an ethanol solution of high concentration of ethanol, specifically, an aqueous ethanol solution containing at least 75% by volume, more preferably at least 90% by volume, of ethanol.

Contact technique In the contact technique of 1) above, the mixture of sesamin components to be refined is contacted with the aqueous medium to form a slurry mixture in which the mixture of sesamin components is partially found. in a dissolved state and then the solids are separated from the mixture. The episesamine has a slightly different solubility in the aqueous medium of other components or impurities (eg, sesamin, diasesamine, etc.) and the episesamin tends to be less soluble. Therefore, when the mixture of sesamin components is brought into contact with the aqueous medium, substances other than episesamine are partially placed in a dissolved state. The amount of the aqueous medium to be used is not limited to any particular value; however, if its quantity is too small, the impurities will dissolve only insufficiently and if it is too much, the separation of the solids will become inefficient. The usual amount is 5-100 times the weight of the mixture of sesamin components to be retined. The contact temperature is usually in the order of 0-70 ° C, preferably 10-50 ° C, and more preferably 20-40 ° C. The method for making contact is not limited in any particular manner and examples include: a method in which the mixture of sesamin components and the aqueous medium are loaded into a container, where they are allowed to stand to have a mutual contact; a method in which the two materials are put in mutual contact in a container equipped with a stirrer; and a method in which they are put in mutual contact in a solid-liquid extractor. If desired, multiple units of these apparatuses can be used so as to allow the mixture of sesamin components to have multiple contacts in two or more stages. The next step in the present invention consists in separating the solids from the slurry mixture obtained by placing the mixture of sesamin components in contact with the aqueous medium. The method for separating the solids is not limited in any particular way and conventionally used solid-liquid separators such as a filter and a centrifuge can be employed. The separated and recovered solids are dried to give a mixture of sesamin components with an improved relative episesamin content.

Recrystallization Technique The refining of episesamine by the recrystallization technique of 2) above can efficiently improve the purity of the episesamine compared to the contact technique of 1) above. The recrystallization technique begins with dissolving the mixture of sesamin components to be retined in the aqueous medium under heating. The amount of the aqueous medium to be used to dissolve the mixture of sesamin components can be adjusted to any desired value and depending on the content of ingredients that are not episesamine or impurities in the mixture of sesamin components, their amount is therefore generally about 5-100 times the amount (in weight ratio) of the mixture of sesamin components. If the amount of the aqueous medium is too small, it takes an excessively long time to dissolve all the sesamin components or sometimes it happens that not all the sesamin components dissolve. On the other hand, if the amount of the aqueous medium is too large, the episesamine will be recrystallized in a lower yield.

The heating temperature for dissolving the mixture of sesamin components is that at which all the sesamin components will dissolve. This temperature, which varies with the purity of the mixture of sesamin components as well as with the type and amount of the solvent to be used to dissolve it, is preferably not higher than the boiling point of the solvent (100.0 ° C if water and 78.3 ° C in the case of ethanol). However, this is not limiting if a reflux tube is used and in the case of using a reflux tube with ethanol as the aqueous medium, the heating can be done up to approximately 80-90 ° C. Starting from room temperature, the temperature is raised to an appropriate heating temperature so that the sesamin components completely dissolve. In the next step, the resulting solution is cooled to precipitate the epísesamine crystal. The cooling is carried out up to 50 ° C or less, preferably up to 40 ° C or less, thus precipitating the epísesamine crystal. If the cooling temperature is too low (specifically, if the cooling is performed up to 4 ° C or less), not only the episense crystal but also the sesamin crystal will be precipitated and the purity of the epísesamine in the crystal obtained by recrystallization it can decrease sometimes; To avoid this problem, it is recommended to cool the solution to the lowest possible temperature zone where only the episensamine crystal can be precipitated.

Subsequently, the suspension containing the episesamine crystal thus obtained is separated in the episesamin crystal and the stock solution. For this separation, conventionally used solid-liquid separators such as a filter and a centrifuge may be employed. In this case, depending on the need, the episesamin crystal can be washed with an aqueous medium, preferably an alcohol, more preferably ethanol. The completely separated stock solution contains sesamin, so it is recovered favorably for a second use as the material to be isomerized. The separated episesamin crystal is then dried to produce a refined form of episesamine or enriched episesamin composition. Drying is preferably carried out under reduced pressure (ca. 1 -100 mm Hg) by heating to about 30-100 ° C, preferably at about 40-80 ° C. This recrystallization process assists in removing the non-episesamine ingredients and impurities in the mixture of sesamin components, so that the sesamin and / or diasesamine having a structure similar to the episesamin can be removed or reduced in content. As a result, the episesamin crystal (enriched episesamin composition) contains episesamin in a concentration greater than 55% by weight, preferably 70% by weight or more based on the total weight of sesamin and episesamin. Observe that if the mixture of The components of sesamin to be retined contain very large amounts of ingredients that are not episesamine or impurities, the recrystallization procedure described above can be repeated as many times as necessary to reduce the content of the impurities.

Sesamin / episesamin blend with an improved episesamin concentration If a sesamin / episesamin mixture with an improved episesamin concentration, specifically, a sesamin / episesamin mixture containing at least 64% by weight of episesamin is used as the mixture of components of sesamin to be retined, the episesamine in the episesamin crystal (enriched episesamin composition) obtained by means of the recrystallization process described above can be markedly improved, thus producing an improvement in the refining efficiency of the episesamin. Although the sesamin / episesamin mixture with an improved episesamine concentration that can be used can be of any type, a specific example is a sesamin / episesamin mixture with an improved episesamin concentration that has been produced by means of the following steps: (1) heating the mixture of sesamin components in an oil or fat under heating; Y (2) selectively crystallize the episesamine by means of a recrystallization technique to produce a composition containing episesamin with an improved episesamin concentration. Here, the oil or fat is preferably chosen from oils or fats that can dissolve sesamin and episesamin in different grades and MCT can be used favorably. If the oil or fat having the sesamin / episesamine mixture dissolved therein is subjected to treatment with an acid catalyst (such as activated clay), the sesamin / episesamin mixture can be obtained with an improved episesamin concentration.

EXAMPLES The refining method of the present invention is described below in detail by reference to examples, which are not intended in any way to limit the present invention.

EXAMPLE 1 Preparation of samples The eight samples shown in the following table 1 were prepared. All the percentages in table 1 as well as in tables 2 and 3 that are going to be explained later are on a basis in weight.

TABLE 1 As samples numbers 1 and 2, mixtures of sesamin and episesamin (mixtures of sesamin / episesamin) purified according to the method described in the official gazette of JP 10-7676 were used. As samples numbers 3-8, prepared and used sesamin / episesamin mixtures that were improved in episesamin concentration by means of the following method: 2.8 g of a sesamin-episesamin mixture (sesamin: 99.1% by weight; episesamin: 0.9% by weight) was mixed with 20 g of an oil or fat (MCT; RIKEN VITAMIN CO., LTD; trademark "ACTOR M-1") and heated to 120 ° C under stirring until the mixture was completely dissolved. To the solution, 0.4 g of activated clay (MIZUSAWA INDUSTRIAL CHEMICALS, LTD., Trade name "GALLEON EARTH V2R") was added and the mixture was stirred at 120 ° C for a continuous period of 30 minutes, followed by filtration to remove the waste clay. The filtrate was coated and slowly cooled; When the temperature of the liquid reached 60 ° C, 2.8 mg of episesamine (100% pure) as seed crystals and crystallization was carried out. By adjusting the crystallization period between 30 minutes and overnight, samples (samples Nos. 3-8) having different concentrations of episesamin in the sesamin / episesamin mixtures were prepared. The resulting suspension was subjected to solid-liquid separation by suction filtration, giving the products containing episesamine to be used in the following experiments.

EXAMPLE 2 Crystallization technique in ethanol - 1 One hundred grams of a 99.5% by volume aqueous ethanol solution were weighed in a 200 ml aubergine-type flask; the flask was then loaded with 5.0 g of each of samples Nos. 1-8 prepared in Example 1; then, the flask was equipped with a reflux tube and the mixture was heated in an oil bath at 90 ° C under agitation for 15 minutes until the mixture dissolved. The solution was allowed to stand overnight at 20 ° C to precipitate the episesamin crystal (enriched episesamin composition). The precipitation crystal was separated by suction filtration and dried at 70 ° C for 60 minutes. The resulting crystal was finely ground in a mortar and a portion of the powder was taken as a sample for HPLC analysis.

The sample thus obtained was subjected to HPLC under the following conditions to analyze the sesamin / episesamin composition.

CLAR conditions Column: Inertsil ODS-3 (product of GL-SCIENCE) 4.6 x 150 mm; Column temperature: 40 ° C Mobile phase: methyl alcohol / water = 7: 3 Flow rate: 1 ml / min Detector: UV 290 nm The results of analysis by means of CLAR are shown in table 2, and the CLAR diagrams for Samples Nos. 2 and 3 are shown in Figure 1. As is clear from table 2 and figure 1, the compositions after recrystallization had higher episesamine concentrations than the mixtures of sesamin components before recrystallization. It was suggested that the episesamin be refined from the mixture of sesamin and episesamin by recrystallization with ethanol. In addition, almost all impurities (including diasesamine) that were not sesamin or episesamin could be removed.

TABLE 2 EXAMPLE 3 Crystallization technique in ethanol - 2 Using the episesamine crystal (enriched episesamin composition) of sample No. 2 (sesamin: 35.32% by weight; episesamin: 63.37% by weight) or the episesamin crystal (enriched episesamin composition) of sample No. 7 ( sesamin: 0.05% by weight, episesamin: 98.80% by weight), both obtained in example 2, recrystallization was carried out in ethanol as in example 2 to precipitate the episesamine crystal (enriched composition of episesamine) and the crystal thus obtained was subjected to HPLC analysis as in example 2. The results are shown in table 3. It was confirmed that upon repeating the recrystallization procedure, the concentration of episesamin was increased.

TABLE 3 From the results of examples 2 and 3, the profiles of episesamine concentration both before and after recrystallization were plotted (figure 2). When the mixture of sesamin components before recrystallization was an enriched episesamin mixture of sesamin components with an episesamin content of 64% or more, the resulting episesamin crystal (enriched episesamin composition) had a significantly improved episesamin concentration. , thus suggesting its high efficiency as the episesamin refining method.

EXAMPLE 4 Crystallization technique in aqua / ethanol - 1 As an aqueous medium, the following five types were used, where water-ethanol (weight ratio) was at 100: 0, 75:25, 50:50, 25:75, and 0: 100 (a 99.5 aqueous ethanol solution % in volume was used as ethanol). Fifty grams of one of these aqueous media were weighed in a 100 ml eggplant-type flask.; the flask was then loaded with 2.5 g of sample No. 2 (sesamin: 42.12% by weight; episesamin: 54.65% by weight) prepared in example 1; then, the flask was equipped with a reflux tube and the mixture was heated in an oil bath at 90 ° C under stirring for 15 minutes until the mixture dissolved. The solution was allowed to stand overnight at 20 ° C to precipitate the episesamin crystal (enriched composition of episesamine), which was subjected to HPLC analysis as in example 2. The results are shown in figure 3. It was suggested that the higher the concentration of ethanol, the higher the concentration of episesamine.

EXAMPLE 5 Crystallization Method in Water / Ethanol - 2 Using sample No. 3 (sesamin: 28.2% by weight; episesamin 69.18% by weight) prepared in Example 1, ie, the mixture of sesamin components with an increased ethanol concentration, the recrystallization was carried out as in Example 4 to precipitate the episesamine crystal (enriched composition of episesamine) and the crystal thus obtained was subjected to HPLC analysis as in example 2. The results are shown in table 4. As in the example 4 (figure 3), it was suggested that the higher the ethanol concentration, the higher the concentration of episesamine in the sesamin / episesamin mixtures that were obtained by recrystallization; however, it was also suggested that without using an aqueous ethanol solution containing more than 50% by volume of ethanol, the episesamine could not be selectively crystallized from the mixture of sesamin components before recrystallization, i.e. , the episesamine could not be refined. It was also confirmed that the concentration of episesamine was markedly improved by using ethanol (100% pure). The quantities (g) of the obtained episesamine crystal were 2.38 g, 2.37 g, 2.21 g, 2.07 g, and 1.63 g for water: ethanol ratios of 100: 0, 75:25, 50:50, 25:75 , and 0: 100, respectively.

EXAMPLE 6 Precipitation technique in ethanol - the effect of pH As aqueous media, the following three types were used, the first being an aqueous ethanol solution at 75% by volume (75% EtOH), the second being one to which 4 N HCl was added to give 75% EtOH (75% EtOH) + HCl), and the latter being one to which 4N NaOH was added to give 75% EtOH (75% EtOH + NaOH). Fifty grams of one of these aqueous media were weighed in a 100 ml aubergine-type flask; the flask was then loaded with 2.5 g of sample No. 2 (sesamin: 42.12% by weight; episesamin: 54.65% by weight) or sample No.3 (sesamin: 28.2% by weight; episesamin: 69.18% by weight) both prepared in Example 1; then, the flask was equipped with a reflux tube and the mixture was heated in an oil bath at 90 ° C under agitation for 15 minutes until the mixture dissolved. The solution was allowed to stand overnight at 20 ° C to precipitate the episesamin crystal (enriched composition of episesamine), which was then subjected to HPLC analysis as in example 2. The results are shown in figure 5. He suggested that the episesamin be refined by crystallization in the aqueous ethanol solution but it was found that the addition of 1 N HCl or 1 N NaOH had no effect on the concentration of episesamin.

EXAMPLE 7 Precipitation technique in ethanol - the effect of cooling temperature Fifty grams of a 99.5% by volume aqueous ethanol solution were weighed into a 100 ml aubergine-type flask; the flask was then loaded with 2.5 g of sample No. 2 (sesamin: 42.12% by weight; episesamin: 54.65% by weight) or sample No.3 (sesamin: 28.2% by weight; episesamin: 69.18% by weight) both prepared in Example 1; then, the flask was equipped with a reflux tube and the mixture was heated in an oil bath at 90 ° C under agitation for 15 minutes until the mixture dissolved. The solution was allowed to stand for 4 hours under different temperature conditions (20 ° C, 4 ° C, and -20 ° C) to precipitate the episesamin crystal (enriched episesamin composition). The obtained episesamine crystal was then subjected to HPLC analysis as in example 2. The results are shown in figure 6. When the sample No. 2 was used, the concentration of episesamin in the episesamin crystal obtained by recrystallization did not depend on the cooling temperature; however, when sample No. 3 (a mixture of sesamin components with an improved episesamine concentration) was used, the concentration of episesamin in the episayamin crystal was reduced in the order of 20 ° C »4 ° C > - 20 ° C, thus suggesting that recrystallization should be perform preferably at approximately 20 ° C. The quantities (g) of the obtained episesamine crystal were 1.63 g, 1.92 g, and 2.01 g for 20 ° C, 4 ° C, and -20 ° C, respectively.

INDUSTRIAL APPLICATION In order to refine episesamin having high activity in vivo from a mixture of sesamin components, in particular, a mixture containing sesamin and episesamin, very few methods have been available, such as column chromatography, which not only involve complicated but also produce small amounts of the composition while presenting only a low efficiency. According to the episesamine refining method of the present invention, enriched episesamin compositions having a high relative episesamin content can be obtained by means of a simple procedure in which the use of high efficiency, economic and large volume of compositions enriched with episesamin has become possible.

Claims (10)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for refining episesamine comprising contacting with an aqueous medium a mixture of sesamin components that is in the solid state or at least part of which is in a dissolved state, thereby forming a slurry, and then separating the solids of the mixture or carry out recrystallization with an aqueous medium, thus producing an enriched composition of episesamine with an increased relative episesamin content.

2. The method for refining episesamine according to claim 1, further characterized in that the mixture of sesamin components to be refined is a mixture of sesamin components containing at least sesamin and episesamin.

3. - The method for refining episesamine according to claim 2, further characterized in that the enriched composition of episesamine has an episesamine concentration greater than 55% by weight, preferably at least 70% by weight, based on the total weight of sesamin and episesamin.

4. - The method for refining episesamine according to any of claims 1 -3, further characterized in that the medium aqueous is water, a water-soluble medium or an aqueous solution of a water-soluble medium.

5. The method for refining episesamine according to claim 4, further characterized in that the aqueous medium is water, an alcohol, or an aqueous alcohol solution.

6. - The method for refining episesamine according to claim 5, further characterized in that the aqueous medium is ethanol or an aqueous ethanol solution.

7. The method for refining episesamin according to any of claims 1-6, further characterized in that it includes recrystallizing the mixture of sesamin components with the aqueous medium to produce the enriched episesamin composition.

8. - The method for refining episesamin according to any of claims 1-7, further characterized in that the mixture of sesamin components with an improved episesamin concentration has been produced by the following steps: (1) dissolving the mixture of components of sesamin in an oil or fat under heating; and (2) selectively crystallizing episesamine by means of a recrystallization technique to produce a composition containing episesamin with an improved episesamin concentration.

9. - The method for refining episesamine according to claim 8, further characterized in that the content of episesamine in the mixture of sesamin components is at least 64% by weight.

10. The method for refining episesamine according to claim 8 or 9, further characterized in that the oil or fat having the mixture of sesamin components dissolved therein is subjected to treatment with an acid catalyst. The method for refining episesamine according to any of claims 1-7, further characterized in that the mixture of sesamin components with an improved episesamin concentration has been produced by means of the following steps: (1) performing distillation molecular in a mixture containing sesamin components that has been refined from sesame oil, thus giving a fraction in which the sesamin components are enriched; and (2) dissolving the fraction in water, a water-soluble solvent or a mixture thereof, optionally adding an alkali, and then precipitating the sesamin components to produce a sesamin / episesamin mixture with an improved episesamin concentration. . 12. The method for refining episesamine according to claim 1, further characterized in that the enriched episesamin composition has an episesamin concentration greater than 55% by weight, preferably at least 70% by weight, based on the weight total of sesamin and episesamin.