Pharmacological studies of kampo medicines on a particular animal model
of clinically related symptoms ought to be conducted.5,6The action of western
medicine directs specifically to the nature and functions of a disease, whereas
the action of kampo medicines attempts to harmonise the disturbed patho-
physiological conditions of the patient (so-called shoclinically) as a whole to
eventually balance a normal physiological environment in the system.
Although it is difficult to clarify shoscientifically, pharmacological studies
based on clinical effects are constructive for the evaluation of kampo medi-
cines. Some kampo medicines are known to exhibit immunopotentiation
activity when they are given to immunocompliant mice, but they also recover
to normal level when they are administered to over-immunostimulated mice,
such as those for adjuvant arthritis, even if they exhibit no effect on normal
mice.
If western medicine and kampo medicines are compared using a globe,
western medicine affects diseases divided by longitude, whereas kampo
medicines affect several whole body systems, which are common in several
diseases and divided by latitude. Thus the targets are different in both
medicines.
Kampo medicines contain many constituents derived from component
herbs. To control the quality of kampo medicines, the exact active
principle(s) has to be identified. As kampo medicines are generally adminis-
tered orally, some components may exist as precursors of active principles
(see Figure 8.2). These ‘inactive’ compounds may be activated by endogenous
factors such as gastric secretions, and intestinal enzymes and bacteria, e.g.
although sennoside A or B in Rhei rhizoma(rhizome of Rheum palmatum
Linne) is known to elicit a cathartic activity, such an effect is not produced
when the sennoside is injected into mice. However, when either sennoside is
administered orally, the cathartic activity is observed. In fact, rhein-anthrone,
a metabolite formed by the action of intestinal bacteria, has been identified
as the active component responsible for the catharsis.7–9In addition, rhein-
anthrone is further metabolised to rhein which displays antibacterial activi-
ties against intestinal anaerobic bacteria.^10 As such, the action of intestinal
bacteria affects the activities of Rhei rhizoma, and a certain feedback mech-
anism may be involved in mild catharsis (Figure 8.5). Therefore studies on
the post-administration products or byproducts of orally administered
kampo medicines are important in the elucidation of the mechanism(s) of
action of a particular kampo formulation.
Orally administered glycyrrhizin of Glycyrrhizae radixproduces a high
concentration of its aglycone, glycyrrhetic acid, and a low level of
glycyrrhizin in circulating blood of rat and human.^11 Therefore glycyrrhetic
acid is an important active principle when kampo medicines containing
Glycyrrhizae radixare administered orally. Efficacy of kampo medicines
cannot be explained by the pharmacological activities of a particular active
236 | Traditional medicine