WHO monographs on selected medicinal plants - travolekar.ru

Cortex Magnoliae
also significantly inhibited local immunoglobulin E (IgE)-mediated passive
cutaneous anaphylactic reaction and reduced the levels of plasma histamine
in a dose-dependent manner (p < 0.05). In vitro, the extract (at
concentrations of 0.001–1.0 mg/ml) concentration-dependently inhibited
the histamine release from rat peritoneal mast cells activated by compound
48/80 or anti-dinitrophenyl IgE (21).
Anti-asthmatic activity
Magnolol stimulates calcium channel activity in tracheal smooth muscle
cells as assessed by the patch clamp technique (22). In whole-cell current
recordings, magnolol reversibly increased the amplitude of potassium
outward currents. The increase in outward current caused by magnolol
was sensitive to inhibition by iberiotoxin (200 nM) or paxilline (1 μM),
but not by glibenclamide (10 μM). In inside-out patches, addition of magnolol
to the bath did not modify single channel conductance, but effectively
enhanced the activity of large conductance calcium (Ca) activated
potassium BK (Ca) channels. Magnolol increased the probability of these
channel openings in a concentration-dependent manner with a median
effective concentration (EC 50
) value of 1.5 μM. The direct stimulation of
these BK (Ca) channels by magnolol may explain the mechanism by
which it acts as an anti-asthmatic compound (22).
Antibacterial activity
An ethanol extract of the bark inhibited the growth of Actinomyces viscosus
ATCC 19246, Streptococcus mutans Ingbritt and Streptococcus sobrinus
6715, with a minimum bactericidal concentration of 0.488, 0.488 and
1.250 g/l, respectively (23). The antimicrobial activities of honokiol and
magnolol were assayed using the agar dilution method and the minimum
inhibitory concentration (MIC) was determined for each compound using
a twofold serial dilution assay. The results showed that honokiol and
magnolol have a marked antimicrobial effect (MIC, 25.0 μg/ml) against
Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella
intermedia, Micrococcus luteus and Bacillus subtilis, but were not
active against Shigella flexneii, Staphylococcus epidermidis, Enterobacter
aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa
(24). An extract of the bark and magnolol inhibited the growth of Helicobacter
pylori in vitro (25).
Anti-gastric ulcer activity
Intragastric administration of aqueous and methanol extract of the crude
drug (400 mg/kg bw) reduced gastric juice secretion and increased the pH
of gastric secretions in mice pretreated with indometacin (26). Indometa-
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