JP5876444B2 - Method for improving concentration of medicinal components in licorice plants - Google Patents

Description

  The present invention relates to a method for improving the medicinal component concentration of a licorice plant in hydroponic cultivation of the licorice plant.

  The licorice genus (licorice genus, scientific name “Glycyrrhiza”, hereinafter the same) is a leguminous perennial that grows mainly in dry areas such as northern China, southern Russia, Central Asia and the Mediterranean. For example, the larva that grows naturally in northern China (scientific name “G. uralensis”, the same shall apply hereinafter) and the Spanish licorice that naturally grows in the Mediterranean region (scientific name “G. glabra”, the same applies hereinafter) are widely known.

  In the field of Oriental medicine (Chinese medicine), dried roots of licorice plants (including strons, the same applies hereinafter) have long been used as the herbal medicine “licorice”. Licorice dry powder and extracts are said to have a relaxing and depleting effect. Therefore, in order to alleviate and harmonize various herbal medicines, licorice is blended in many Chinese herbal medicines such as Anchu-san, Shikimikoto, Juzentaihoyu, and ginseng. In addition, licorice, alone, is said to have a soothing effect on sore throat and cough, and is also used as an analgesic / antitussive.

As a main medicinal component of licorice, glycyrrhizin (Glycyrrhizin, C ₄₂ H ₆₂ O ₁₆ , CAS number: 1405-86-3, the same shall apply hereinafter) is known. Glycyrrhizin is one of the triterpene glycosides and is abundant in roots of licorice plants. Glycyrrhizin is known to have an anti-inflammatory action and a strong sweetness. Therefore, it is widely used as a medicine, cosmetics, sweeteners, etc. alone. Glycyrrhizin is mainly produced by extraction and purification from the roots of licorice plants.

  In addition, licorice contains flavonoids having high pharmacological activity in addition to glycyrrhizin, such as liquiritigenin, liquiritin, isoliquitigenin and the like. These medicinal components have different medicinal effects. Therefore, it is preferable that the herbal licorice contains not only glycyrrhizin but also these medicinal components in an appropriate amount or more.

  In many cases, wild licorice plants are harvested and used as raw materials such as herbal licorice. On the other hand, problems of environmental destruction and resource depletion due to over-exploitation of licorice plants have become apparent. Therefore, it is desired to establish a cultivation / proliferation method for stably supplying licorice plants.

  As an approach for stably supplying licorice plants, for example, in Patent Document 1, in the method for cultivating licorice plants in tube cultivation in an alley, the permeated water into the soil is limited, and dry conditions are created. Means have been devised to increase the glycyrrhizin content by restraining the root.

On the other hand, in a joint study in which the present inventors also participated, recently, by selecting a licorice plant strain that can be subcultured and proliferated while maintaining a high ratio of glycyrrhizin content, and by closed-system facility cultivation such as hydroponics Successful cultivation of licorice plants (see Patent Document 2).
JP 2012-170344 A JP2012-100533A

  As described above, in the joint research in which the present inventors participate, cultivation of licorice plants by closed-system facility cultivation such as hydroponics has become possible. Thereby, it becomes possible to artificially control the environmental conditions for cultivating licorice plants, and it becomes easy to give special environmental conditions that are not in the natural environment to the plant body.

  On the other hand, since the cultivation of licorice plants by closed-system facility cultivation such as hydroponic cultivation has been virtually impossible, little is known about the relationship between the concentration of medicinal components of licorice plants and environmental conditions. Not obtained. For this reason, little is known about the environmental conditions for improving the concentration of medicinal components in licorice plants.

  Therefore, the present invention is a means for improving the concentration of medicinal components in cultivation of licorice plants by closed-system facility cultivation such as hydroponics by examining environmental conditions for improving the concentration of medicinal components of licorice plants. The purpose is to provide.

  In the present invention, as a specific means for improving the concentration of a specific medicinal component, there is provided a medicinal component concentration improving method including any one or a plurality of steps described below in hydroponic cultivation of a licorice plant.

(1) A step of growing a licorice plant by adjusting the temperature of the culture solution to 20 to 35 ° C.,
(2) A process of low-temperature cultivation with a culture solution of 19 ° C or lower before harvesting,
(3) After harvesting, the step of storing the root part of the licorice plant under 1-30 ° C. conditions;
(4) A step of drying the root of the genus plant after harvesting at 20 to 50 ° C.

  For example, after sufficiently growing the plant body for a predetermined period, low temperature cultivation is performed with a culture solution of 19 ° C. or lower for a predetermined period immediately before harvesting. Thereby, the density | concentration of glycyrrhizin and liquiritin in a root part can be improved, and the density | concentration of lithigenin and isoliquiritigenin can also be maintained.

  On the other hand, when low temperature cultivation is performed with a culture solution of 19 ° C. or lower, the growth of the plant body is greatly suppressed. Therefore, in the stage before performing the step of low-temperature cultivation with a culture solution of 19 ° C. or lower, the temperature of the culture solution is adjusted to 20 to 35 ° C. to grow licorice plants. Thereby, since the growth of the plant body can be promoted, the harvest time can be advanced and the medicinal component concentration at the time of harvest can be improved. That is, the temperature of the culture solution is adjusted to 20-30 ° C., and after sufficiently growing the plant body, low temperature cultivation is performed for a relatively short period of time, so that a high content of specific medicinal components in the root part of the genus plant The concentration of other medicinal components can be maintained without substantially decreasing.

  Moreover, you may grow a daylily plant on long-day conditions. In hydroponic cultivation of licorice plants, the light environment and the like can be adjusted relatively easily. And as a result of the study by the present inventors, in cultivation of licorice plants by closed system cultivation such as hydroponics, long-day conditions are set rather than creating short-day conditions in winter as in open field cultivation. It was found that sustaining can improve the concentration of medicinal components such as lithigenin and liquiritin while maintaining the glycyrrhizin content in the main root of the licorice plant. Therefore, during the growing period of licorice plants, the concentration of a specific medicinal component in the root of the licorice plant can be increased by maintaining the long-day condition instead of the short-day condition, and the concentration of other medicinal components Can generally be maintained without lowering.

  In the harvesting stage after cultivation and growth of licorice plants, the concentration of glycyrrhizin and lithigenin in the roots of licorice plants is maintained by storing the roots of licorice plants for a specified period of time at 1-30 ° C. As it is, the concentration of liquiritin and isoliquiritigenin can be improved.

  In addition, at the harvesting stage after cultivation and growth of licorice plants, the concentration of glycyrrhizin and lithigenin in the roots of licorice plants is maintained by drying the licorice plant roots at 20-50 ° C. As it is, the concentration of liquiritin and isoliquiritigenin can be improved.

  For harvesting in open field cultivation, etc., environmental conditions at the time of harvesting are uneven, and it is necessary to consider the time for transportation and transportation to processing facilities. In closed-system facility cultivation such as liquid cultivation, it can be performed more simply and efficiently.

  As described above, the concentration of a specific medicinal component in the root part of the licorice plant can be increased by adjusting the environmental conditions in each stage after cultivation and cultivation of the licorice plant, before harvesting, and after harvesting, The concentration of other medicinal components can also be maintained without substantially decreasing.

  According to the present invention, it is possible to increase the concentration of a specific medicinal component in the root part of a licorice plant.

<About the stage of cultivation and cultivation of licorice plants>
In the present invention, licorice plants are basically cultivated and cultivated by closed-system facility cultivation such as hydroponics. The advantage of closed-system cultivation is that plants of uniform quality can be produced without being affected by external weather, plants can be produced without being affected by seasonal fluctuations, and the cultivation environment conditions can be controlled. There is.

  In the present invention, closed-system facility cultivation is a cultivation form in which the environmental conditions of the cultivation space can be artificially controlled, and not only a cultivation form completely shut off from the outside world but also a certain boundary with the outside world, such as a greenhouse. Widely includes cultivation forms in the formed facilities and equipment. Moreover, the cultivation form which controls the environmental conditions of cultivation space, utilizing natural environments, such as sunlight, may be sufficient.

  In the present invention, hydroponics broadly encompasses all cultivation methods that provide nutrient nutrients necessary for plant growth as liquid fertilizer. That is, it broadly encompasses both cases where a medium for supporting roots is used and when it is not used. In the case of licorice plants, it may be preferable to use a medium in order to grow the main root. The medium is not particularly limited as long as it can support roots. For example, rock wool, gravel, hydroball or the like may be used. In addition, for example, coco pate (soil conditioner deposited and fermented with fiber fibers forming the coconut shell), pumice sand (volcanic pumice), peat moss, vermiculite, perlite, etc., and small containers such as pots Hydroponic cultivation may be performed by filling a bag or the like, transplanting a plant body, and immersing the whole container or bag in a nutrient solution.

The nutrient solution may be water or an aqueous solution containing components necessary for plant growth such as nitrogen, phosphorus, potassium and metal components, and any known solution can be used, and is not particularly limited. . For example, ammonia nitrogen, nitrate nitrogen, phosphoric acid (P ₂ O ₆ ), potassium (K ₂ O), magnesium (MgO), manganese (MnO), boron (B ₂ O ₂ ) Those containing components such as iron (Fe), copper (Cu), zinc (Zn) and molybdenum (Mo) can be used.

  In the present invention, a plant of the genus Licorice (scientific name “Glycyrrhiza”, hereinafter the same) may be any plant that contains at least glycyrrhizin at the root. For example, Ural licorice (scientific name "G. uralensis"), Spanish licorice (scientific name "G.glabra"), butterfly licorice (scientific name "G.inflata"), scientific name "G.acanthocarpa", scientific name "G.aspera", scientific name "G. astragalina", scientific name "G.bucharica", scientific name "G.echinata", scientific name "G.eglandulosa", scientific name "G.foetida", scientific name "G.foetidissima", scientific name "G.gontscharovii", scientific name " G.iconica, scientific name G.korshinskyi, scientific name G.lepidota, scientific name G.pallidiflora, scientific name G.squamulosa, scientific name G.triphylla, scientific name G.yunnanensis, these licorice genus Varieties of plants and the like can be applied, Uralanthus and Spanish daylily are preferred, Uralanthus is more preferred, Gu2-2-1 strain, Gu2-3-2 strain, GuTS71 shown in Patent Document 2 -08IV1 strain and GuTS71-08IV2 strain are most preferable.

  The planting method etc. of a plant body are not specifically limited. For example, seedlings may be grown from seeds, and the seedlings may be subjected to hydroponics, or licorice plant strains obtained by hydroponics, field cultivation, tissue culture, etc. may be subjected to hydroponics. Alternatively, a root or stem section having a predetermined length may be prepared from these strains, and the section may be subjected to hydroponics.

  Although it does not specifically limit about the period which grows and grows a plant body by hydroponic culture, About 4 months-4 years after planting a plant body are suitable.

  In the period of cultivating and growing plants by hydroponics, the temperature of the culture solution is adjusted to 20 to 35 ° C, more preferably 20 to 30 ° C, and even more preferably 22 to 28 ° C. It is preferable to train. Thereby, since the growth of the plant body can be promoted, the harvest time can be advanced and the medicinal component concentration at the time of harvest can be improved. In addition, since the ratio of respiratory exhaustion to the accumulation of photosynthetic products increases when the temperature of the culture solution is 30 ° C. or higher, the degree of growth of the plant body is lower than when the temperature of the culture solution is 22 to 28 ° C. Lower. On the other hand, when the temperature of the culture solution is 19 ° C. or lower, the growth of the plant body is greatly suppressed.

  Moreover, in the period which cultivates and grows a plant body by hydroponics, it is preferable to maintain a long-day condition without creating a short-day condition in winter. By maintaining the long-day condition, it is possible to improve the concentration of medicinal components such as lithigenin and liquiritin while maintaining the glycyrrhizin content in the main root part of the licorice plant.

  In the present invention, the long day condition is an environmental condition in which the light period is 16 hours or more per day. It is preferable to control the light environment so that at least 3 months before harvesting, more preferably 6 months before harvesting, and more preferably 9 months before harvesting are long-day conditions.

<Before harvesting licorice plants>
In the present invention, it is preferable to perform low temperature cultivation for a predetermined period after the plant body is sufficiently grown and before harvesting.

  When the licorice plant is cultivated at a low temperature, the growth of the plant body is greatly suppressed, while the concentration of glycyrrhizin and liquiritin in the root can be improved, and the concentration of lithigenin and isoliquiritigenin can also be maintained. Therefore, as described above, after sufficiently growing the plant body for a predetermined period without lowering the temperature of the culture solution, before harvesting, by performing low temperature cultivation for a predetermined period, without suppressing the growth of the plant body, The concentration of specific medicinal components can be improved.

  In low temperature cultivation, it is preferable to adjust the temperature of the culture solution to 1 to 19 ° C, more preferably 1 to 17 ° C. Considering the point that the suppression of plant growth does not prolong, the period of low temperature cultivation is preferably 1 week to 3 months immediately before harvesting, more preferably 2 weeks to 2 months, 3 to 6 weeks is most preferred.

<At the time of harvesting and after harvesting licorice plants>
For example, it is harvested between about 4 months and 4 years after planting. Since a large amount of glycyrrhizin and other medicinal components are contained in the root portion, the root portion may be mainly collected. In the present invention, the root portion includes a main root portion (portion where the minor axis of the root portion is 1 mm or more) and stron.

  After harvesting, the roots of licorice plants may be stored under 1-30 ° C conditions. Thereby, the concentration of liquiritin and isoliquiritigenin can be improved while maintaining the concentration of glycyrrhizin and lithigenin in the root. Although it does not specifically limit about a storage period, 1-6 weeks are suitable, 1-5 weeks are more suitable, and 1-4 weeks are the most suitable.

  Moreover, you may dry-process the root part of a licorice plant on 20-55 degreeC conditions after a harvest. Thereby, the concentration of liquiritin and isoliquiritigenin can be improved while maintaining the concentration of glycyrrhizin and lithigenin in the root.

  As means for performing the drying treatment, known dry heat treatment means can be widely employed. The drying treatment time is not particularly limited, and for example, the drying treatment may be performed for 2 to 10 days, more preferably 3 to 8 days, and most preferably 4 to 6 days.

  In Example 1, in the cultivation of licorice plants by closed system cultivation such as hydroponics, the effect of light environment on the concentration of medicinal components in the licorice plants was examined.

  The licorice plant is a perennial plant, and the growth of the above-ground part is stagnant in the winter, and it germinates and the emergence is promoted in the spring, and the above-ground part grows vigorously. Therefore, in this example, it was examined whether or not the concentration of medicinal components can be increased by performing supplementary light in winter and increasing the daily integrated light quantity (DLI) more than under natural light.

  As a test plant, Uralphanthus GuTS71-08IV1 strain (refer to Patent Document 2, sold by Medicinal Plant Resource Research Center, National Institute of Biomedical Innovation) was used.

  A container (with an internal volume of 15 L) was placed in an incubator (product name “MIR-553”, manufactured by Sanyo Electric Co., Ltd.), a culture solution was placed in the container, and a styrene foam cover was put on the container. The root part of the cutting plant seedling of the test plant was fixed in the hole formed in the polystyrene foam, so that the root of the main root part was immersed in the culture solution, and the test plant was bred by submerged hydroponics for 4 months. Next, it was transplanted to a polypot (diameter 14 cm, internal volume 2 L) filled with rock wool, immersed in the culture solution in the container together with the polypot, and hydroponically cultivated for 5 months to raise seedlings. The seedlings were grown again by submerged hydroponics for one month, then transplanted into a polypot (diameter 15 cm, internal volume 4 L) filled with hydroballs, immersed in the culture solution in the container together with the polypot, about 1 During the months, hydroponic cultivation was conducted and seedlings were raised.

As the culture solution, 1-fold concentration of Ceramis liquid fertilizer (Mars, Incorporated) was used, and topdressing was performed once every 3 days. The temperature of the culture solution was adjusted to about 25 ° C. A white fluorescent lamp (product name “FPL55EX-L”, manufactured by Iwasaki Electric Co., Ltd.) was used as the light source. The environmental conditions in the incubator were set as follows. Light period: 16h / day, PPF (photosynthetic effective photon flux at plant community surface): 350μmol / m ² · s, temperature: light period 25 ° C, dark period 20 ° C, relative humidity: 30-70%, CO ₂ Concentration: 1,000 μmol / mol.

  Subsequently, a cultivation shelf was manufactured in a greenhouse capable of adjusting the temperature without blocking natural light, and a tray was set thereon, and a culture solution was placed in the tray.

  As a natural light zone, on November 10, 2011, the seedlings transplanted in a polypot (diameter 15 cm, internal volume 4 L) filled with hydroballs were transferred into the greenhouse and immersed in the culture medium in the tray. Until the day, hydroponics were carried out.

  In addition, as a supplementary light zone, on January 12, 2011, the seedlings transplanted into a polypot (diameter 15 cm, internal volume 4 L) filled with hydroballs were transferred to another greenhouse, and immersed in the culture solution in the tray together with the polypot, Until April 18, 2012, hydroponic cultivation was conducted.

In each greenhouse, the temperature was adjusted so as not to fall below 17 ° C. In the supplementary light zone, in addition to natural light, sodium lamps are used to combine natural light and supplementary light so that the light period is 16h / day or more and the DLI (PPF integrated light amount) is 10 mol / m ^2. did. The temperature and solar radiation in each greenhouse were measured and controlled by a combined environmental control system (“UECS system”, Stellar Green Co., Ltd.). The relative humidity and CO ₂ concentration were not particularly controlled.

  On April 18, 2012, the plants in each test area were harvested, and the main root part with a diameter of 1 mm or more was dried with hot air at 50 ° C for several days. Then, the sample was powdered, precisely weighed 100 mg, and accurately 50% 7 mL of ethanol was added, and the mixture was treated with an ultrasonic cleaner for 30 minutes and with a vortex mixer for 1 minute to extract the eluted components. The extract was centrifuged (4,500 rpm, 3 minutes), and 300 μL of the supernatant was centrifuged (15,000 rpm, 1 minute, 20 ° C.) with Ultra Free MC (ultrafiltration membrane, manufactured by Millipore). The filtrate was subjected to a liquid chromatograph mass spectrometer (LC / MS / MS) to analyze four types of compounds, glycyrrhizin, liquiritin, liquiritigenin and isoliquiritigenin.

  Nexera / LSMS-8030 (Shimadzu Corporation) was used as a measuring device, and TSKgel ODS-100S (diameter 2.0 mm × 150 mm, injection amount 1 μL, manufactured by Tosoh Corporation) was used as a column. A mobile phase was mixed with acetonitrile and 1% acetic acid, and the flow rate was set to 0.2 mL / min and the column temperature was set to 40 ° C.

  The results are shown in FIG. FIG. 1 is a graph showing the effect of winter supplementary light on the concentration of medicinal components. In FIG. 1, the “GL” graph represents the concentration of glycyrrhizin at the root of the harvested plant body, the “LG” graph represents the concentration of the same lithigenin, and “LQ” represents the concentration of the same liquiritin. The graph “ISLG” is a graph showing the concentration of the same isoliquiritigenin. In each graph, “Natural Light Zone” represents the concentration of medicinal components in plants grown in the natural light zone, and “Supplementary Light Zone” represents the concentration of medicinal components in plants grown in the supplementary light zone, respectively. The vertical axis of each graph is the medicinal component concentration (unit: dry weight% (% DW)). Moreover, the bar in each graph represents standard deviation (n = 4), and the asterisk represents that there is a significant difference at the 1% level in the t test.

  As shown in FIG. 1, the concentration of medicinal components in the supplementary light zone was equal to that in the natural light zone with glycyrrhizin, and significantly increased with lithigenin and liquiritin. This result shows that by maintaining the long-day condition, the concentration of medicinal components such as lithigenin and liquiritin can be improved while maintaining the glycyrrhizin content in the roots of the licorice plant.

  In Example 2, the influence of the culture solution temperature on the concentration of medicinal components in the licorice plant was examined in the cultivation of the licorice plant by closed system cultivation such as hydroponics.

  A container is installed in the incubator, and finally, under the same environmental conditions as in Example 1, it is transplanted into a polypot (diameter: 15 cm, internal volume: 4 L) filled with hydroballs, and immersed in the culture solution in the container together with the polypot. For 4 months, hydroponic cultivation was carried out to prepare test seedlings.

  Divide each strain into 4 test zones, and adjust the culture temperature to 15 ° C, 20 ° C, 25 ° C, and 30 ° C in the incubator, respectively. Continued hydroponic cultivation for 30 days with the setting.

  The growth amount of each test plant body when the culture solution temperature was adjusted to each temperature was calculated by subtracting the total living body weight at the end of the test from the total living body weight of each test plant body before the start of the test. As a result, the growth amount was highest in the test group in which the culture solution temperature was adjusted to 25 ° C., whereas in the test group in which the culture solution temperature was adjusted to 15 ° C., the growth amount was almost zero.

  At the end of the test, each test plot was harvested, and the roots of each test plant were analyzed for the four compounds of glycyrrhizin, liquiritin, liquiritigenin, and isoliquiritigenin in the same procedure as in Example 1.

  The results are shown in FIG. FIG. 2 is a graph showing the effect of culture solution temperature on medicinal component concentration. In FIG. 2, the “GL” graph represents the concentration of glycyrrhizin at the root of the harvested plant, the “LG” graph represents the concentration of the same lithigenin, and “LQ” represents the concentration of the same liquiritin. The graph “ISLG” is a graph showing the concentration of the same isoliquiritigenin. “T15” in each graph indicates the concentration of medicinal components in the plant grown in the test plot adjusted to 15 ° C., and “T20” was grown in the test plot adjusted to 20 ° C. “T25” is the concentration of medicinal components in the plant body, “T25” is the concentration of medicinal components in the plant body cultivated in the test zone adjusted to 25 ° C., and “T30” is the temperature of the medium. The concentration of the medicinal component in the plant body cultivated in the test plot adjusted to 1 is represented, and the vertical axis of each graph represents the medicinal component concentration (unit: dry weight% (% DW)). Also, the bar in each graph shows the standard deviation (n = 5), the different lowercase letters in each graph (between “a” and “b”, “a” and “c”, “a” And “bc” and between “b” and “c”) indicate that there is a significant difference at the 5% level in the Tukey-Kramer method.

  As shown in FIG. 2, in the test plot in which the culture solution was adjusted to 15 ° C. and the plant body was cultivated, the concentrations of glycyrrhizin and liquiritin in the roots were significantly increased compared to other test plots, and lithigenin and No significant decrease in the concentration of lithigenin was observed.

  As described above, in this example, it was found that the growth of a plant can be promoted by cultivating the plant by adjusting the culture solution to 25 ° C. In addition, by growing the plant body by adjusting the culture solution to 15 ° C, the growth of the plant body is suppressed, but the concentration of glycyrrhizin and liquiritin in the root can be improved, and the concentration of lithigenin and isoliquiritigenin is also maintained I understood that I could do it.

  Therefore, the results of this example were obtained by cultivating a plant body by adjusting the culture solution to 25 ° C., and growing the plant body, and then adding a treatment for adjusting the culture solution to 15 ° C. before harvesting. Shows that certain medicinal components of plants can be improved.

  In Example 3, the effect of the storage temperature after harvesting on the concentration of medicinal components in the licorice plant was examined.

  After cutting the stron of Uralphanthus GuTS71-08IV2 strain (refer to Patent Document 2, distributed from National Institute of Biomedical Resources, Medicinal Plant Resource Research Center), and immersing the slice in 100-fold dilution of plant vitality Menedale, It was inserted into a soil pot and hydroponically cultivated in an artificial weather room for 2 months while giving Menedale dilution. Place a tray in the artificial weather chamber, transplant the test plant body into a polypot (diameter 15 cm, internal volume 4 L) filled with hydroballs in the room, immerse the whole polypot in the culture solution in the container for 10 months Then, hydroponics were performed. The environmental conditions and the culture solution were the same as in Example 1.

  Ten months after transplanting the test plants into the polypot, the plants were harvested, the main roots were collected and cut vertically in half, one for the control group and the other for the test group. In the control group, the collected main root fragments were directly lyophilized for 3 days, and then analyzed for four compounds of glycyrrhizin, liquiritin, liquiritigenin, and isoliquiritigenin in the same manner as in Example 1. In the test group, the collected main root fragments were each stored at 1-4 ° C, -30 ° C, -13 ° C, 4 ° C, or 25 ° C for 1 to 4 weeks, and then 3 days. After freeze-drying, the same procedure as in Example 1 was used to analyze four types of compounds: glycyrrhizin, liquiritin, liquiritigenin, and isoliquiritigenin.

The results are shown in FIG. FIG. 3 is a graph showing the effect of storage temperature after harvesting plants on the concentration of medicinal components. In FIG. 3, the “GL” graph represents the glycyrrhizin concentration, the “LG” graph represents the lithigenin concentration, the “LQ” represents the liquiritin concentration, and the “ISLG” represents isoliquiritic. It is a graph showing the density | concentration of genin. In each graph, “-80 ° C” indicates the measured value of medicinal component concentration in the test group with a storage temperature of -80 ° C, and the control group fragment collected from the same plant was lyophilized without storage treatment. The measured value of “-30 ° C” is the measured value of medicinal component concentration in the test plot with the storage temperature set to −30 ° C., and the control plot taken from the same plant is stored. The measured value when freeze-dried without `` -13 ℃ '' is the measured value of medicinal component concentration in the test group with storage temperature -13 ℃, and the fragment of the control group collected from the same plant, The measured value when freeze-dried without storage treatment, "4 ° C" is the measured value of medicinal component concentration in the test group with the storage temperature set to 4 ° C, and the fragment of the control group collected from the same plant body Measured values when freeze-dried without storage treatment, "25 ° C" is the test section where the storage temperature was 25 ° C Represents the measured value of medicinal component concentration and the measured value when freeze-dried fragments of the control group collected from the same plant without storage treatment, and the numbers 1 to 4 are the storage period (Unit: week). The vertical axis on the left side of each graph represents the vertical axis of the bar graph, and is the concentration of medicinal components (unit: mg / g DW; the ratio of the dry weight of each medicinal component to the dry weight of the main root). The vertical axis on the right side of each graph represents the vertical axis of the line graph, and represents P _INC (increment percentages). The value of P _INC is the difference between the dry weight of the taproot unit in the control group and the dry weight of the taproot portion in the test group was divided by the dry weight of the taproot unit in the control group was calculated by multiplying by 100. In FIG. 3, “control group” is a graph of measured values of a sample lyophilized without storage treatment as a control group, and “test group” is the concentration of medicinal component in the test group where each storage process was performed. “P _INC ” represents a graph of measured values, and “P _INC ” represents a graph of the above increase rate. Bars in each graph indicate standard deviation (n = 3 or 4), one asterisk is significantly different at the 5% level in the t test, and two asterisks are significantly different at the 1% level in the t test Represents each.

  As shown in FIG. 3, after harvesting the plant body, it is stored at 4 ° C. to 25 ° C. for 1 to 4 weeks, so that the concentration of glycyrrhizin and lithigenin in the main root of the licorice plant is maintained, while maintaining the concentration of liquiritin and The concentration of lithigenin could be improved significantly.

  In Example 4, the influence of the drying temperature after harvesting on the concentration of medicinal components in the licorice plant was examined.

  Ten months after transplanting the test plant grown in the same manner as in Example 3 to the polypot, the plant was harvested, the main root was collected and cut vertically in half, one in the control group and the other in the other. Was provided to the test area. In the control group, the collected main root fragments were directly lyophilized for 3 days, and then analyzed for four compounds of glycyrrhizin, liquiritin, liquiritigenin, and isoliquiritigenin in the same manner as in Example 1. In the test group, the collected main root fragments were heat-treated at 30 ° C., 40 ° C., 50 ° C., and 60 ° C. for 5 days, respectively, and the sample was pulverized, and glycyrrhizin and liquiritin were processed in the same manner as in Example 1. Analysis of four compounds, liquiritigenin and isoliquiritigenin.

The results are shown in FIG. FIG. 4 is a graph showing the effect of the drying temperature after harvesting plants on the concentration of medicinal components. In FIG. 4, the “GL” graph represents the glycyrrhizin concentration, the “LG” graph represents the lithigenin concentration, the “LQ” represents the liquiritin concentration, and the “ISLG” represents isoliquiritic. It is a graph showing the density | concentration of genin. In each graph, “30 ° C.” indicates the measured value of the medicinal component concentration in the test group dried at 30 ° C., and the measured value when freeze-dried the fragment of the control group collected from the same plant body is “40”. “° C.” is the measured value of the medicinal component concentration in the test section dried at 40 ° C., and the measured value when the control section fragment collected from the same plant was freeze-dried, “50 ° C.” is 50 ° C. Measured value of medicinal component concentration in the test group dried with, and measured value when freeze-dried fragments of the control group collected from the same plant, "60 ° C" is a test dried at 60 ° C The measured value of the medicinal component concentration in the ward and the measured value when the control fragment obtained from the same plant was freeze-dried are shown. The vertical axis on the left side of each graph represents the vertical axis of the bar graph, and is the concentration of medicinal components (unit: mg / g DW; the ratio of the dry weight of each medicinal component to the dry weight of the main root). The vertical axis on the right side of each graph represents the vertical axis of the line graph, and represents P _INC (increment percentages) as in Example 3. In FIG. 4, “control group” is a graph of measured values of a sample freeze-dried as a control group, and “test group” is a graph of measured values of medicinal component concentrations in the test groups subjected to each drying treatment. “P _INC ” represents the graph of the above increase rate, respectively. Bars in each graph indicate standard deviation (n = 4 or 5), one asterisk is significantly different at the 5% level in the t test, and two asterisks are significantly different at the 1% level in the t test Represents each.

  As shown in FIG. 4, after harvesting the plant, it is dried at 30 ° C. to 50 ° C., so that the concentration of glycyrrhizin and lithigenin in the main root of the licorice plant is not reduced, and liquiritin and isoliquiritic The concentration of genin could be improved significantly.

In Example 1, the graph which shows the influence which supplementary light of winter has on a medicinal component density | concentration. In Example 2, the graph which shows the influence which a culture solution temperature has on a medicinal component density | concentration. In Example 3, the graph which shows the influence which the storage temperature after plant harvesting has on a medicinal component density | concentration. In Example 4, the graph which shows the influence which the drying temperature after plant body harvest has on a medicinal component density | concentration.

Claims (5)

In hydroponic cultivation of licorice plants,
A method for improving the concentration of medicinal components of licorice plants, comprising a step of low-temperature cultivation with a culture solution of 19 ° C. or lower before harvesting.   The method for improving the concentration of a medicinal component according to claim 1, wherein, before the step, the temperature of the culture solution is adjusted to 20 to 35 ° C to grow a licorice plant.   The method for improving the concentration of medicinal components according to claim 2, wherein the licorice plant is grown under long-day conditions.   The method for improving the concentration of medicinal components according to any one of claims 1 to 3, comprising a step of storing the root of the licorice plant after the harvest under 1 to 30 ° C conditions.   The method for improving the concentration of medicinal components according to any one of claims 1 to 4, comprising a step of drying the root of the genus plant after the harvesting under conditions of 20 to 50 ° C.

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