NIS - libdoc.who.int - World Health Organization

WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
ergy production (59). Other constituents of Radix Ginseng, such as vanillic
and salicylic acid, have also been reported to have “antifatigue” activity
in rats (68). Furthermore, the antioxidant activity of ginseng was
associated with both the ginsenosides and the flavonoid constituents (31,
69). The ginsenosides protected pulmonary vascular endothelium against
free-radical-induced injury (69).
Mice given ginseng extract or ginsenosides Rb 1
and Rg 2
orally during
passive avoidance response tests showed an improvement in learning ability
which was negatively influenced by stress (30), and rats showed improved
retention of learned behaviour (70). Ginsenosides Rg 1
and Rb 1
are the active
nootropic constituents of the drug (66), and improve memory and learning
in normal as well as cognition-impaired animals. The mode of action involves
an increase in the synthesis and release of acetylcholine, and a decrease
of brain serotonin levels (66). In cerebral and coronary blood vessels,
extracts of Radix Ginseng produced vasodilatation, which improved brain
and coronary blood flow (71). The vasodilatory activity of the ginsenosides
appears to be primarily due to relaxation of vascular smooth muscles. The
ginsenosides block the constricting effects of norepinephrine in isolated
aorta strips, and inhibit the uptake of 45 Ca 2+ in the membrane and sarcolemma
of rabbit heart tissue. Inhibition of Ca 2+ uptake in the muscle membrane
contributes to the mechanism of vasodilatation (71).
A number of polypeptides and glycans isolated from Radix Ginseng,
named GP and panaxans A–E, respectively, have demonstrated hypoglycaemic
activity when given intraperitoneally to mice (72, 73). Two of the
glycans, panaxans A and B, have been shown to stimulate hepatic glucose
utilization by increasing the activity of glucose-6-phosphate 1-dehydrogenase,
phosphorylase a, and phosphofructokinase (72). Panaxan A did
not affect plasma insulin levels or insulin sensitivity, but panaxan B elevated
the plasma insulin level by stimulating insulin secretion from pancreatic
islets, and further enhanced insulin sensitivity by increasing insulin
binding to receptors (72). The panaxans are not active after oral administration.
Administration of GP (intravenously or subcutaneously) to mice
or rats decreased blood glucose and liver glycogen levels (73). Radix Ginseng
also contains a number of other constituents with hypoglycaemic
activity (72, 74). Adenosine, isolated from a water extract of Radix Ginseng,
enhanced lipogenesis and cyclic AMP accumulation of adipocytes,
and some of the ginsenosides inhibited ACTH-induced lipolysis, suppressed
insulin-stimulated lipogenesis, and stimulated the release of insulin
from cultured islets (72).
Subcutaneous administration of a ginseng extract enhanced the mating
behaviour of male rats (75). The drug further stimulated spermatogenesis
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