WHO monographs on selected medicinal plants - travolekar.ru

Cortex Magnoliae
The protective effect of magnolol against hypoxia-induced cell injury
in cortical neuron-astrocyte mixed cultures was assessed after exposure of
the cells to chemical hypoxia (0.5 mm potassium cyanide). Treatment with
magnolol (10 and 100 μM) significantly reduced potassium cyanideinduced
lactose dehydrogenase release in a concentration-dependent
manner (30).
The effects of magnolol on the course of sepsis, survival rate and biochemical
parameters were analysed in rats with induced sepsis. Intragastric
administration of magnolol, at doses ranging from 10 -9 g/kg to 10 -5 g/
kg bw, administered either before or after induction of sepsis by cecal ligation
and puncture did not alter the course of sepsis induced by two cecal
punctures. However, when one cecal puncture was performed, a moderately
evolving type of sepsis was induced, and the survival rate of
affected rats was significantly improved by pretreatment with 10 -7 g/kg
magnolol (p < 0.05). The intensity of lipid peroxidation in plasma, liver
and lung of septic rats was also attenuated in a treatment-dependent
manner (31).
Anxiolytic activity
In rat brain membranes, honokiol and magnolol at a concentration of
5.0 μM, enhanced binding of [3H]muscimol and [3H]flunitrazepam to
the -aminobutyric acid receptor, but honokiol was 2.5 to 5.2 times more
potent than magnolol. Honokiol and magnolol also enhanced the potentiating
effect of 200 nM -aminobutyric acid on [3H]flunitrazepam binding
with EC 50
values of 0.61 μM and 1.6 μM. Honokiol and magnolol increased
[3H]muscimol binding by approximately 68% with EC 50
values
of 2.3 and 12.0 μM, respectively (32).
In elevated plus-maze tests, treatment of mice with honokiol prolonged
the time spent in the open arms, showing an anxiolytic effect. Seven
daily treatments with 0.1–1 mg/kg bw honokiol, demonstrated an
anxiolytic effect with the optimal dose at 0.2 mg/kg bw. These results
suggest that honokiol is the chemical responsible for the anxiolytic effect
of the water extract of the bark in vivo (33).
Cardiovascular effects
The effect of magnolol on coronary circulation and vascular resistance
was assessed in anaesthetized rabbits using a Doppler velocimetry probe.
Thirty-nine rabbits received intravenous injection of either vehicle (n =
5), magnolol (10 -6 –10 -4 g/kg bw) or nitroglycerin. Magnolol did not change
blood pressure or coronary blood flow velocity, but at a dose of 10 -4 g/kg,
decreased coronary vascular resistance significantly more than vehicle
(p < 0.001). Nitroglycerin increased coronary blood flow velocity and
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