**5. Necessity of alternative sources of supply**

As was discussed in the previous section, the recent increase in the price of Chinese licorice in the Japanese market is considered to be due to a combined effect of an increase in its demand

<sup>11</sup> **Figure 8** presents Japanese demand and supply of Chinese licorice following [5]. The price and quantity traded of Chinese licorice are indicated on the vertical and horizontal axes, respectively. The initial demand schedule, a rightward shift in demand, the initial supply schedule, a leftward shift in the supply schedule, the equilibrium, the equilibrium price, the equilibrium quantity, the new equilibrium, the new equilibrium price, and the new equilibrium quantity are labeled D, D', S, S', E, Pe, Qe, E', Pe', and Qe', respectively.

<sup>12</sup> As in **Figure 8**, the rightward shift of the demand schedule and the leftward shift of the supply schedule counteract the respective effects on quantity traded. Hence, changes in quantity traded depend on the comparative strength of influences from demand and supply.

and decrease in its supply. Although the depreciation of the Japanese yen may be improved by changes in each country's economic situation, a decrease in the harvest of native licorice cannot be improved without taking precautionary measures. Leaving the market could potentially cause further increases in the price and a reduction of trading volume. Eventually, the trade of licorice in the Japanese market may become difficult to sustain.

To prevent such a situation, the price and trading volume of licorice must be maintained by increasing its supply. In this section, we discuss attempts to establish licorice cultivation methods, which could potentially serve as a supply source of an alternative to native Chinese licorice. If cultivated licorice can be used in Japanese pharmaceutical products in the same way as its native strains, then decreases in the supply of native licorice could be offset with cultivated licorice.

**Figure 9** visualizes the situation described above.13

As shown in **Figure 9**, due to the combined effect of an increase in demand and a decrease in supply, the current equilibrium condition of Chinese licorice in the Japanese market is considered to be at *E*'. Utilizing cultivated licorice as an alternative to native licorice could help shift the supply curve to the right, leading to an equilibrium point at *E*". At *E*", the price of licorice will be lower than in the previous situation (i.e., price at the equilibrium (*E*')).

**Figure 9.** Market condition when utilizing cultivated licorice as an alternative source.

<sup>13</sup> Drawn from Ref. [5], **Figure 9** simulates Japanese demand and supply for licorice when cultivated licorice becomes an alternative. The price and quantity traded are indicated on the vertical and horizontal axes, respectively. The initial demand schedule, a rightward shift, the initial supply schedule, a leftward shift, initial equilibrium price and quantity, and new equilibrium price and quantity are labeled D, D', S, S', E, Pe, Qe, E', Pe', and Qe', respectively. In addition, equilibriums following the introduction of cultivated licorice, the third equilibrium price, and the third equilibrium quantity are labeled E", Pe", and Qe", respectively.

However, using cultivated licorice as an alternative to native Chinese licorice is not an easy task. This is because the amount of cultivated licorice needed as an ingredient in Japanese pharmaceutical products is often different from that of native licorice. More specifically, the glycyrrhizin content (an ingredient contained in licorice root) of cultivated licorice is often lower than that of native licorice [1].

and decrease in its supply. Although the depreciation of the Japanese yen may be improved by changes in each country's economic situation, a decrease in the harvest of native licorice cannot be improved without taking precautionary measures. Leaving the market could potentially cause further increases in the price and a reduction of trading volume. Eventually,

To prevent such a situation, the price and trading volume of licorice must be maintained by increasing its supply. In this section, we discuss attempts to establish licorice cultivation methods, which could potentially serve as a supply source of an alternative to native Chinese licorice. If cultivated licorice can be used in Japanese pharmaceutical products in the same way as its native strains, then decreases in the supply of native licorice could be offset with

As shown in **Figure 9**, due to the combined effect of an increase in demand and a decrease in supply, the current equilibrium condition of Chinese licorice in the Japanese market is considered to be at *E*'. Utilizing cultivated licorice as an alternative to native licorice could help shift the supply curve to the right, leading to an equilibrium point at *E*". At *E*", the price of

licorice will be lower than in the previous situation (i.e., price at the equilibrium (*E*')).

**Figure 9.** Market condition when utilizing cultivated licorice as an alternative source.

quantity are labeled E", Pe", and Qe", respectively.

<sup>13</sup> Drawn from Ref. [5], **Figure 9** simulates Japanese demand and supply for licorice when cultivated licorice becomes an alternative. The price and quantity traded are indicated on the vertical and horizontal axes, respectively. The initial demand schedule, a rightward shift, the initial supply schedule, a leftward shift, initial equilibrium price and quantity, and new equilibrium price and quantity are labeled D, D', S, S', E, Pe, Qe, E', Pe', and Qe', respectively. In addition, equilibriums following the introduction of cultivated licorice, the third equilibrium price, and the third equilibrium

the trade of licorice in the Japanese market may become difficult to sustain.

cultivated licorice.

**Figure 9** visualizes the situation described above.13

50 Biological Activities and Action Mechanisms of Licorice Ingredients

Because of this, the content of pharmaceutical products produced using cultivated licorice must conform to the standards of official compendiums such as the Japanese Pharmacopoeia XIV (JP XIV)14 (e.g., see Ref. [1]).

A number of groups are performing research on the production of cultivated licorice that can be used in pharmaceutical products in Japan.

Reference [6] reports an investigation of the quality variation of the licorice in the Japanese market in the period 1986–2000. The main contribution of this investigation was to propose a method of distinguishing the different types of Chinese licorice. More specifically, during the investigation period, the average glycyrrhizin content of Dongbei‐Gancao, a type of licorice mainly traded in the Japanese market, was found to be higher than that of a different type of licorice, Xibei‐Gancao. On the other hand, the root specific gravity of Dongbei‐Gancao is often lower than that of Xibei‐Gancao. The investigation also found that some Dongbei‐Gancao has high root specific gravity, which is not consistent with the aforementioned characteristic of Dongbei‐Gancao. The investigation suggests that the licorice that was thought to be Dongbei‐ Gancao seems to correspond to Ditou‐Gancao, which is a Chinese licorice different from both the Dongbei and Xibei types.

Reference [7] reports a study of the cultivation of *Glycyrrhiza uralensis* (the scientific names of one type of licorice) in the eastern region of Neimenggu (Inner Mongolia). In this study, seeds of *G. uralensis* were sown in May 1998 and its seedling roots were transplanted to the field the following May. It was found that the glycyrrhizin content of 4‐year‐old lateral root newly grown from the transplanted seedling taproot exceeds the Japanese Pharmacopoeia XIV standard. However, the study concludes that utilizing the cultivated licorice as a substitute for the native licorice traded in the Japanese market is still difficult, because even though the glycyrrhizin content of the cultivated licorice satisfies JP XIV, it is still lower than that of the native licorice currently traded in the Japanese market. The study emphasizes the necessity of improvements in the selection of seedlings and cultivation methods.

In reference [3], the feasibility of the medicinal use of cultivated licorice was tested by com‐ paring the licorice roots cultivated in eastern Neimenggu and that used in medical applica‐ tions. According to this study, the 4‐year‐old adventitious licorice roots cultivated in eastern Neimenggu may be a suitable substitute for licorice conforming to JP XIV.

Attempts are also being made to cultivate licorice in Japan. In reference [8], a comparative study of 10 types of licorice strains cultivated in the Kyoto Herbal Garden of Takeda Pharma‐

<sup>14</sup> JP XIV standards appear in the 14th edition of the Japanese Pharmacopoeia, which was published to regulate the properties and quality of drugs by the Japanese Minister of Health, Labor and Welfare after consultation with the Pharmaceutical Affairs and Food Sanitation Council. The 17th edition is the latest version. For details, see http:// www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000066597.html [Accessed: 2016‐09‐17].

ceutical Co. Ltd. was undertaken to understand the differences of the features of licorice of different origins. According to this latter study, the 10 types of licorice belong to either the Chinese or the Kazakhstani types. These types show some differences, namely the glycyrrhizin content of Chinese type is higher than that of Kazakhstani type.

In reference [4], a study of the cultivation of licorice in Inner Mongolia was conducted. This study aimed to confirm the origin of the plant by comparing their cultivated strain to native strains in the Xinjiang Uygur Autonomous Region of China.15 The study concludes that their cultivated strain of licorice is most likely the *G. uralensis*, which is the main raw material of licorice used in Japan.

In reference [9], a study investigated the use of cultivated licorice in Inner Mongolia as a method to compensate for the reduced supply of native licorice. Specifically, the chemical and pharmaceutical properties of cultivated licorice root and those of licorice prepared from its native plant were compared. In this study, boiled water extracts of cultivated and native licorice were found to have similar antispasmodic effect on carbachol‐induced contraction in mice jejunum.16 Moreover, the glycycoumarin content (one of the components contained in licorice) of boiled water extract of 4‐year‐old cultivated root and that of native licorice was also found to be similar. Thus, the study in reference [9] concluded that the cultivated licorice root could be considered an adequate substitute in the face of restrictions on the harvest of native licorice.

Some researchers are attempting to use the cultivation of licorice to prevent desertification, mainly in Mongolia. This is referred to as high‐value‐added greening, since it is effective in both providing a supply of licorice and combatting desertification. In reference [10], deserti‐ fication is explained as an environmental problem caused by both natural environmental phenomena, such as irregular precipitation and the lowering of the ground water level, and anthropogenic causes such as overharvesting of native plants.

Many of the studies referenced here take advantage of greening soil materials (GSMs). In reference [11], GSMs are a mixture of sand and compost that can be inexpensively and easily applied to the ground. This material contains more water than ordinary soils and, therefore, can be thought of as a simple self‐watering system that does not require artificial water supplies.

There have been various reports on the effect of using GSMs to cultivate licorice.

To prevent desertification, in reference [10], licorice was experimentally planted in arid areas of Mongolia. In this experiment, GSMs were used for planting licorice. As GSMs have more than 10 times the water and nutrient‐holding capacity in comparison with desert ground, a correlation between the survival ratio of licorice and GSMs was demonstrated (i.e., a positive relationship between the amount of water in GSMs and the survival ratio of licorice).

Reference [11] reports field agricultural experiments conducted in areas where licorice did not grow naturally. In this experiment, researchers concluded that a larger volume of GSMs could

<sup>15</sup> Native strains of licorice in the latter area are *Glycyrrhiza inflata, G. glabra, and G. uralensis*.

<sup>16</sup> Carbachol is a kind of medicine (cholinergic agent).

maintain the survival rate for licorice higher than smaller types. In other words, GSMs are helpful in increasing the survival rate of licorice.

ceutical Co. Ltd. was undertaken to understand the differences of the features of licorice of different origins. According to this latter study, the 10 types of licorice belong to either the Chinese or the Kazakhstani types. These types show some differences, namely the glycyrrhizin

In reference [4], a study of the cultivation of licorice in Inner Mongolia was conducted. This study aimed to confirm the origin of the plant by comparing their cultivated strain to native

cultivated strain of licorice is most likely the *G. uralensis*, which is the main raw material of

In reference [9], a study investigated the use of cultivated licorice in Inner Mongolia as a method to compensate for the reduced supply of native licorice. Specifically, the chemical and pharmaceutical properties of cultivated licorice root and those of licorice prepared from its native plant were compared. In this study, boiled water extracts of cultivated and native licorice were found to have similar antispasmodic effect on carbachol‐induced contraction in mice

of boiled water extract of 4‐year‐old cultivated root and that of native licorice was also found to be similar. Thus, the study in reference [9] concluded that the cultivated licorice root could be considered an adequate substitute in the face of restrictions on the harvest of native licorice.

Some researchers are attempting to use the cultivation of licorice to prevent desertification, mainly in Mongolia. This is referred to as high‐value‐added greening, since it is effective in both providing a supply of licorice and combatting desertification. In reference [10], deserti‐ fication is explained as an environmental problem caused by both natural environmental phenomena, such as irregular precipitation and the lowering of the ground water level, and

Many of the studies referenced here take advantage of greening soil materials (GSMs). In reference [11], GSMs are a mixture of sand and compost that can be inexpensively and easily applied to the ground. This material contains more water than ordinary soils and, therefore, can be thought of as a simple self‐watering system that does not require artificial water

To prevent desertification, in reference [10], licorice was experimentally planted in arid areas of Mongolia. In this experiment, GSMs were used for planting licorice. As GSMs have more than 10 times the water and nutrient‐holding capacity in comparison with desert ground, a correlation between the survival ratio of licorice and GSMs was demonstrated (i.e., a positive

Reference [11] reports field agricultural experiments conducted in areas where licorice did not grow naturally. In this experiment, researchers concluded that a larger volume of GSMs could

There have been various reports on the effect of using GSMs to cultivate licorice.

relationship between the amount of water in GSMs and the survival ratio of licorice).

15 Native strains of licorice in the latter area are *Glycyrrhiza inflata, G. glabra, and G. uralensis*.

16 Carbachol is a kind of medicine (cholinergic agent).

Moreover, the glycycoumarin content (one of the components contained in licorice)

The study concludes that their

content of Chinese type is higher than that of Kazakhstani type.

52 Biological Activities and Action Mechanisms of Licorice Ingredients

strains in the Xinjiang Uygur Autonomous Region of China.15

anthropogenic causes such as overharvesting of native plants.

licorice used in Japan.

jejunum.16

supplies.

In reference [12], a geo‐environmental and climate survey was conducted to investigate the environmental conditions in the licorice‐habitat area. In this study as well, GSMs were used experimentally to plant licorice in arid Mongolian land. This experiment reached several conclusions. First, there was a great difference between the licorice habitat and non‐habitat areas in terms of the amount of water in the ground. Specifically, at points deeper than 20 cm below the surface, the water content was higher in the habitat area of licorice than in non‐ habitat areas. Second, covering the ground surface with vinyl‐mulching sheets helps licorice to survive by maintaining a high water content. Third, GSMs help licorice to survive by maintaining a high water content. Fourth, licorice can survive if soil water content of at least 8% is maintained.

In reference [13], agricultural experiments were conducted in sandy ground to simulate arid regions and non‐habitat regions of licorice in Mongolia, using GSMs to establish suitable soil water and calcium conditions, setting up outer layer processing for the survival and growth of licorice. In this experiment, some beneficial results were obtained. Notably, the active ingredient content of the cultivated licorice root tended to rise when using GSMs whose available moisture was three to 10 times higher than that in Mongolian soils.

In reference [14], the five bioactive components of licorice (liquiritin, liquiritigenin, glycyrrhi‐ zin, isoliquiritin, and isoliquiritigenin) were examined using four types of licorice grown in four distinct environments in Northern China during 2010–2011. This study explored how the five bioactive components are affected by various factors, such as climate (i.e., an increase in the duration of sunshine increases glycyrrhizin while declining rainfall promotes the accu‐ mulation of liquiritigenin and isoliquiritigenin).

As was discussed in this section, the effects of a decrease in the harvest of native Chinese licorice cannot be underestimated as it has the potential to cause further price increases and reductions in trading volume. Eventually, the trading of licorice in the Japanese market may become difficult to sustain.

To prevent such a situation, the price and trading volume of licorice must be maintained by increasing its supply. One of the potential solutions is to establish cultivation methods for licorice.

However, using cultivated licorice as an alternative supply source is not an easy task, since the amounts of active ingredients in cultivated licorice are often different from those in the native licorice used for pharmaceutical products in Japan [1].

As noted in this section, a number of groups are attempting to establish cultivation methods for licorice that can be used in the pharmaceutical industry in Japan.

However, to conclude that the quality of cultivated licorice is equivalent to that of native licorice, more demonstrations are required. More specifically, further studies are needed to devise methods for increasing the glycyrrhizin content of cultivated licorice.
