WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
decreased coronary vascular resistance in a dose-dependent manner
(p < 0.01) (34). Magnolol (concentration 10–100 μg/ml) inhibited norepinephrine-induced
phasic and tonic contractions in rat thoracic aorta in
vitro (35).
Miscellaneous activities
Honokiol and magnolol increase choline acetyl-transferase activity, inhibit
acetylcholinesterase, promote potassium-induced acetylcholine release
and exhibit neurotrophic function in vitro. In conscious, freelymoving
rats a dose of honokiol or magnolol (10 -4 –10 -6 M) was perfused
into the hippocampus via a dialysis probe. The results showed that at a
dose of 10 -4 M honokiol or magnolol markedly increased extracellular
acetylcholine release to 165.5% and 237.83% of the basal level, respectively.
However, lower concentrations of either compound failed to elicit
significant acetylcholine release (36).
The effects of magnolol on thermoregulation and hypothalamic release
of 5-hydroxytryptamine were assessed in normothermic rats and in febrile
rats treated with interleukin-1 beta. Intraperitoneal administration of magnolol
(25.0–100.0 mg/kg bw) produced a decrease in colon temperature, an
increase in foot skin temperature, a decrease in metabolic rate and a decrease
in the endogenous release of 5-hydroxytryptamine in the rat hypothalamus.
Depletion of 5-hydroxytryptamine in rat brain, produced by
intracerebroventricular pretreatment with 5,7-dihydroxytryptamine, attenuated
the magnolol-induced hypothermia and cutaneous vasodilation,
and decreased metabolism (37).
Muscle relaxation effects
Intraperitoneal administration of an ether extract of the crude drug, at a
dose of 1.0 g/kg bw induced a loss of the righting reflex 30 minutes after
injection. In mice, intraperitoneal administration of magnolol (50.0–
500.0 mg/kg bw) produced sedation, ataxia, muscle relaxation and a loss
of righting reflex. Intraperitoneal administration of magnolol and honokiol
(50.0 mg/kg bw) to young chicks suppressed spinal reflexes (38–40).
Toxicity
The median lethal dose after intraperitoneal injection of a decoction is
6 g/kg bw in mice, and the median lethal dose is 4.25 g/kg bw in cats after
intravenous administration (19, 34).
Clinical pharmacology
No information was found for single-entity preparations of Cortex
Magnoliae.
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