WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
the expression of choline acetyltransferase and trkA mRNAs in the basal
forebrain and nerve growth factor mRNA in the hippocampus (42).
The effect of chronic treatment with ginsenoside Rb1 (5.0 mg/kg/day,
intraperitoneal administration for 4 days) was assessed in scopolamineinduced
amnesia. The results indicated that treatment with ginsenoside
Rb1 can partially attenuate scopolamine-induced amnesia without sedative
effects (43). In vitro studies show that ginsenoside Rb1 has no effect
on quinuclidinyl benzylate binding or on acetylcholinesterase activity, but
facilitates the release of acetylcholine from hippocampal slices. The increase
in acetylcholine release was associated with an increased uptake of
choline into nerve endings; however, calcium influx was unaltered. Thus,
the ability of ginsenoside Rb1 to prevent memory deficits may be related
to facilitation of acetylcholine metabolism in the central nervous system
(43). In situ hybridization studies show that ginsenoside Rb1 increases the
expression of choline acetyltransferase and trk mRNAs in the basal forebrain
and nerve growth factor mRNA in the hippocampus (42).
Pharmacokinetics
The pharmacokinetics of ginsenosides A1, A2, B2 and C were studied in
rabbits in a one-component open model. Ginsenoside C (protopanaxadiol
group ginseng saponin) had a significantly longer half-life, greater
plasma protein binding, and lower metabolic and renal clearance than ginsenosides
A1, A2 and B2 (protopanaxatriol group ginseng saponins). All
ginsenosides except ginsenoside A1 were slowly absorbed after intraperitoneal
administration. The ginsenosides were not found in rabbit plasma
or urine samples after oral administration. The observed differences in the
pharmacokinetics of the ginsenosides may be attributed to differences in
protein binding (44). Analysis of the ginsenosides and their sapogenins in
rabbit plasma and urine was performed. Linear relationships of peak
height ratio to weight ratio were obtained for ginsenosides (A1, 20–350 μg;
A2, 20–400 μg; B2, 20–300 μg; C, 20–500 μg), and sapogenins (panaxadiol
or panaxatriol, 10–200.0 μg) in 0.1 ml (44).
Toxicology
The effect of a standardized extract of the roots (4% ginsenosides w/w)
and individual ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf and Rg1) on CYP1
catalytic activities was assessed in vitro. The extract decreased human recombinant
CYP1A1, CYP1A2 and CYP1B1 activities in a concentrationdependent
manner. The extract was 45-fold more potent than Panax ginseng
in inhibiting CYP1A2. Rb1, Rb2, Rc, Rd, Re, Rf and Rg1, either
separately or as a mixture and at the levels reflecting those found in an
inhibitory concentration of 100.0 μg/ml of the extract, did not influence
236