**2.6 Fangji**

*Plant Extracts*

**2.5 Seven-relation compatibility**

application' for the treatment of certain diseases [76].

Multiple herbs can be combined in TCM, with up to 20 herbs in one formula, yielding very complex decoctions. Such a complex formula is called Fangji in Chinese, and it is adjusted for each individual patient under the guidance of TCM theory. At times, single herbs are used to prepare decoctions for treatment, and for instance, *Radix Astragali membranacei* (Huang qi 黄芪) is used on its own to treat lung disease. The combination of herbs within one formula is under the guidance of the 'seven-relation compatibility' (**Table 2**), which includes the following: 'mutual accentuation', 'mutual enhancement', 'mutual counteraction', 'mutual suppression', 'mutual antagonism' and 'mutual incompatibility' between two herbs. In addition, single herbs can be used under the 'seven-relation compatibility' in an 'individual

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**Table 2.**

*Explanation and application of 'seven-relation compatibility' [24].*

Fangji is defined as formulae composed of multiple herbs with integrated medical effects, and it is guided by 'Jun Chen Zuo Shi' theory [3]. One TCM formula generally consists of four different kinds of herbal medicine, which is called 'jun', 'chen', 'zuo' and 'shi' (**Figure 12**). Each of them plays a different role within the formula. All of these medicinal herbs work harmoniously together to achieve therapeutic effects and bring the balance of Yin and Yang back to the human body [77]. In the TCM formula theory system, 'jun' means the 'master' and provides the principal therapeutic effect for the disease; and 'chen' represents the 'advisor' which functions as the second principal medicinal component, supporting the medical efficacy of the 'jun' medicine. 'Zuo' represents the 'soldier' and is applied to treat associated symptoms or reduce toxicity of the 'jun' medicine. 'Shi' represents the 'guide' which can direct other medicines to the diseased organ or contribute to the harmony of all herbs in the formula [3]. For

**Figure 12.**

*The principle of 'Jun Chen Zuo Shi' theory [79].*

instance, *Radix glycyrrhizae* (Gan cao 甘草) is the most commonly used 'shi' medicine, since its sweet flavour can improve the taste of formula decoction and enhance the harmony of the combined herbs [78]. For single-herb formulas, the medicinal herb is a 'jun' medicine (master medicine), which shows the principal medical effects.

For example, 'Ma-huang-tang' is a formula traditionally used to treat inflammatory liver disease and consists of *Ephedra sinica* Stapf (Ma huang 麻黄), *Ramulus cinnamomi Cassiae* (Gui zhi 桂枝), *Semen pruni Armeniacae* (Xing ren 杏仁) and *Radix glycyrrhizae* (Gan cao 甘草) (**Figure 13**). Ma huang works as the master medicine, which provides the main anti-inflammatory effects in the treatment of lung diseases. Gui zhi works as the advisor medicine and assists Ma huang to function well, which compiles the 'xiang shi' ('mutual enhancement') from the 'sevenrelation compatibility'. Xing ren is the soldier medicine and enhances the efficacy of Ma huang. Gan cao functions as the guide medicine, which can adjust the properties of other medicines and improve the harmonisation in the formula. The overall efficacy of the TCM formula is a result of the mixture of chemical components in the multiple medicinal herbs [76]. However, it was reported that pure and active components which were separated and purified from single or multiple herbs are different in their chemical profile when compared to traditional decoctions [80]. This may be due to synergistic effects in the complex medicine or to chemical reactions and other changes which may occur during the decoction procedure.

**Figure 13.** *Composition of herbs and roles in 'Ma-huang-tang' formula.*
