JPH10202002A - Improved method for extracting extract of guava leaf - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a high quality extract of guava leaves by subjecting guava leaves to extraction with water or a hydrophilic solvent, partially concentrating the extracted liq., removing a material slightly soluble in the extracting solvent and concentrating the partially concd. liq. again. SOLUTION: Guava leaves are subjected to extraction with water, a hydrophilic solvent or a mixture of them. The hydrophilic solvent is preferably prim. alcohol or lower ketone and is especially preferably methanol, ethanol, butanol or acetone. The extraction is preferably carried out with a mixed solvent consisting of water and such a hydrophilic solvent. The resultant extracted liq. is partially concd. under reduced pressure until the volume is reduced to 1-10%, preferably about 50-60% of the original volume at room temp. to 70 deg.C, preferably about 30-40 deg.C. A material slightly soluble in the extracting solvent is removed from the concd. liq. by sedimentation or extraction and the treated partially cond. liq. is properly concd. optionally under reduced pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improved extraction method for obtaining a high quality extract from guava leaves.

[0002]

2. Description of the Related Art Since ancient times, in China and other Southeast Asian countries, aqueous solutions in which guava leaves have been decocted have been used as antidiarrheals and as a gastrointestinal medicine. In recent years, in Japan, guava leaf extract has attracted attention as being effective for diabetes, hypertension, constipation, obesity, diarrhea, and the like. Guava leaves contain a large amount of tannins, vitamins, flavonols, essential oils, and the like, and it is considered that any one of these components alone or in combination has the above effects. Therefore, there is an increasing demand for guava leaf extract not only for the treatment of specific diseases but also for general health maintenance, but the method of infusing for a long time is extremely cumbersome and difficult, so that it can be more easily used and distributed. Guava leaf extract is available on the market. These extracts are mainly obtained by industrially extracting guava leaves with a water-alcohol or lower ketone solvent, but the extracts obtained in this way have a nasty unpleasant odor and are not only tasteless but also soluble in water. Not good (1 g water 20
(It becomes turbid even if dissolved in 0 ml).

[0003]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a method for efficiently obtaining a guava leaf extract having good flavor and water solubility, and as a result, extracted guava leaves with an extraction solvent. From the partially concentrated solution obtained by appropriately concentrating the extract obtained by removing the poorly soluble component, it was found that the problems related to flavor and water solubility in conventional guava leaf extract were solved, and the present invention completed. That is, the present invention provides a method for extracting guava leaves with water or a hydrophilic solvent, or a mixture thereof, partially concentrating the obtained extract, removing a substance that is hardly soluble in the extraction solvent from the partially concentrated solution, It is intended to provide a method for producing a guava leaf extract, which comprises concentrating the concentrated solution again. Guava leaf extract obtained in this manner (hereinafter sometimes referred to as extract)
Has no unpleasant odor or taste that is peculiar to conventional extracts, has good flavor, and has excellent water solubility, and can be used for foods, pharmaceuticals, quasi-drugs and the like.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION
1) extraction of guava leaves, 2) partial concentration and treatment of concentrated liquid,
And 3) Reconcentration can be roughly divided into three steps. The first step can be performed by a known method conventionally used for extracting guava leaves. However, to obtain a good quality extract efficiently, guava leaves are extracted with water or a hydrophilic solvent, or a mixture thereof. As the hydrophilic solvent, primary alcohols or lower ketones are preferable, and alcohols such as methanol, ethanol and butanol and acetone are more preferable. Most preferred is ethanol. In order to sufficiently extract a water-soluble component and a component soluble in alcohol or lower ketone, it is preferable to extract with a mixed solvent of water and a hydrophilic solvent thereof. Usually, the mixing ratio of water and the mixed solvent is in the range of 6: 4 to 3: 7,
It is not limited to this. The amount of the extraction solvent used varies depending on the state of guava leaves. In the case of dried guava leaves, a solvent having a weight ratio of 8 to 10 times is used. The extraction temperature is also arbitrary, but it is heated to 50 to 70 ° C., and at normal pressure or 1 to 1.5 kg /
Under pressure of the CM ^2, extracted from a few tens of minutes to several hours.

[0005] In order to partially concentrate the extract, the extract is kept at room temperature to
70 ° C., preferably 30 to 40 ° C., having a volume of about 1 to
The solution is concentrated under reduced pressure to 100%, preferably about 50 to 60%. As a method for removing a substance that is hardly soluble in the extraction solvent from the concentrated liquid, a method in which the partially concentrated liquid is left under low-temperature conditions and solid-liquid separation is performed to remove a sedimentable substance (sedimentation method) There is a method (extraction method) of treating with a hydrocarbon solvent to remove organic solvent-soluble components, and any of these methods can provide a desired high-quality extract. Alternatively, these methods may be appropriately used in combination. In the case of the sedimentation method, use
Under low-temperature conditions of ５０50 ° C., preferably 5-20 ° C., the insoluble components are allowed to settle by allowing them to stand for a time sufficient for sedimentation, usually 5 to 24 hours, and then subjected to centrifugation or filtration under reduced pressure to perform solid-liquid separation. In the case of the extraction method, the partially concentrated liquid
Extraction is performed at room temperature with a hydrocarbon solvent of up to three times the volume, for example, hexane, heptane, or the like, and liquid separation is performed to remove components soluble in the solvent.

Next, the treated partially concentrated solution is concentrated to an appropriate amount as it is or under reduced pressure in the same manner as described above. The obtained final concentrate (liquid extract) can be used as it is, but may be spray-dried or freeze-dried to obtain a powder extract. The guava leaf extract obtained by the conventional method is excellent in water solubility (it does not become cloudy even at 1 g / 200 ml), is light-colored, has no unpleasant odor or taste such as blue odor, and is suitable for eating and drinking. In addition, by appropriately selecting the conditions (the degree of concentration, the degree of sedimentation, the type of extraction solvent, etc.) in the above-mentioned partial concentration and / or the treatment of the obtained partially concentrated liquid,
An extract having desired properties can be obtained, and such improved methods are also included in the scope of the present invention.

As described above, according to the method of the present invention, useful components are contained in the components extracted by the ordinary extraction method.
It is possible to obtain a high-quality extract containing no components that adversely affect the taste, smell, color, and the like. This means
It means that useful components such as tannin can be more concentrated and quality can be improved. In addition, according to the method of the present invention,
Using existing equipment, a high-quality extract can be obtained efficiently and easily. Since the obtained extract contains useful components of guava leaves, it can be widely used as a raw material for health foods, health drinks, pharmaceuticals and the like.

Hereinafter, the present invention will be described with reference to examples. Example 1 Water-ethanol (1: 1) was added to 200 g of crushed dried guava leaves.
1320 ml of the mixture of 1) is added, and the mixture is heated at 60 to 62 ° C. for 1 hour. The mixture was filtered through filter paper, and 680 ml of the same mixture as above was added to the residue, followed by extraction again, to obtain a total of 1440 ml of filtrate. 40 ml was taken from the filtrate, concentrated under reduced pressure at about 40 ° C. to remove the alcohol, and lyophilized to obtain 0.93 g of a stock extract extract. 1400m of remaining filtrate
l is divided into 5 equal portions (A to E) in 280 ml portions,
The treatment was as follows. A: It is put in a refrigerator at 5 ° C. as it is and settled for 10 hours, and then centrifuged at 2,000 rps × 6 min to perform solid-liquid separation. The precipitate was freeze-dried to obtain 0.32 g of precipitate A. The liquid was concentrated under reduced pressure at about 40 ° C. to remove the alcohol in the same manner as described above, and then freeze-dried, and the extract A6.
3 g were obtained. B: Concentrate under reduced pressure to 180 ml at about 40 ° C, subject the concentrated liquid to solid-liquid separation by sedimentation at 5 ° C and centrifugation as in A above, and concentrate the liquid under reduced pressure at about 40 ° C , And then freeze-dried to obtain an extract powder B5.
6 g were obtained. The solid is freeze-dried as it is and the precipitate B0.8
5 g were obtained. C to E: C is up to 150 ml at about 40 ° C., D is 130
After concentration under reduced pressure to 100 ml and E to 100 ml, respectively, the mixture was treated in the same manner as in B to obtain extract extracts C, D and E and precipitates C, D and E. The tannin content of each obtained extract powder and precipitate was quantified. The results are shown in Table 1 below.

Example 2 Water-ethanol (1: 1) was added to 50 g of crushed dried guava leaves.
330 ml of the mixture of 1) was added, and the mixture was heated at 65 ° C. for 1 hour. The mixture was filtered with filter paper, and the residue was mixed with 170 m of the same mixture as above.
1 and the mixture was extracted again to obtain a total of 360 ml of filtrate.
The filtrate was concentrated under reduced pressure at about 40 ° C. to 160 ml, divided into two equal parts (F and G), and treated as follows. F: Put in a refrigerator at 15 ° C. and settle overnight, then 200
The mixture is centrifuged at 0 rpsx6 min to perform solid-liquid separation. The precipitate was freeze-dried to obtain 1.1 g of precipitate F. The liquid was concentrated under reduced pressure at about 40 ° C. to remove alcohol, and then freeze-dried to obtain 3.2 g of extract powder F as described above. G: After extracting three times with 50 ml of n-hexane, the n-hexane layer was removed by liquid separation, the aqueous layer was concentrated under reduced pressure at about 40 ° C. to remove the organic solvent, and then lyophilized to 2.3 g. A hexane-treated extract (extracted extract G) was obtained. As a result of quantifying the tannin content of each of the obtained extract powders F and G, the tannin content of both was almost the same (F: G = 1: 1.0
1). ☆

[Table 1]

Example 3 Water-ethanol (1: 1) was added to 200 g of crushed dried guava leaves.
1320 ml of the mixture of 1) was added, and the mixture was heated at 60 to 62 ° C. for 1 hour. The mixture was filtered with filter paper, and 680 ml of the same mixture as above was added to the residue, followed by extraction again to obtain a total of 1540 ml of filtrate. The filtrate was partially concentrated at about 40 ° C. to 850 ml. This partially concentrated solution was placed in a refrigerator at 5 ° C., allowed to settle for 10 hours, and then subjected to solid-liquid separation treatment by vacuum filtration.
The liquid was concentrated under reduced pressure at about 40 ° C. to remove alcohol, and then lyophilized to obtain 31.9 g of extract H. The solid was freeze-dried to obtain 6.33 g of precipitated H. The components of the extracted extract H and the precipitate H thus obtained were analyzed. The results are shown in Table 2 below. ☆

[Table 2]

[0011]

As is clear from the above examples and the results shown in Tables 1 and 2, according to the method of the present invention, high quality guava leaf extract can be obtained.

Claims (5)

[Claims] 1. Guava leaves are extracted with water or a hydrophilic solvent, or a mixture thereof, and the obtained extract is partially concentrated. After removing a substance which is hardly soluble in the extraction solvent from the partially concentrated solution, the extract is partially concentrated. A method for producing a guava leaf extract, comprising concentrating the solution again. 2. The method according to claim 1, wherein the hydrophilic solvent is an alcohol or a lower ketone. 3. The method according to claim 1, wherein the partial concentration is performed at room temperature to 70 ° C. by concentration under reduced pressure to 10 to 10% of the volume of the original extract. 4. The method of removing a hardly soluble substance comprises removing the substance which precipitates by leaving the partially concentrated liquid under low temperature conditions, and / or treating the partially concentrated liquid with a hydrocarbon solvent, The method according to any one of claims 1 to 3, which is performed by removing a component. 5. The method according to claim 4, wherein the step of leaving the partially concentrated liquid under low-temperature conditions is to leave the liquid at a temperature of 0 to 50 ° C. for a time sufficient for sedimentation, and the hydrocarbon solvent is hexane or heptane. Method.