WHO monographs on selected medicinal plants - travolekar.ru

Cortex Salicis
Pharmacology
Experimental pharmacology
Anti-inflammatory activity
Similar to salicylates, such as acetylsalicylic acid, extracts of the crude drug
are thought to act by inhibiting the activity of cyclooxygenase and thereby
inhibiting the synthesis of prostaglandins, which play a role in inflammation,
fever and pain. Acetylsalicylic acid inhibits the synthesis of prostaglandins
through the acetylation of the enzyme cyclooxygenase. Salicylic
acid, and the salicylates that lack an acetyl group, reduce prostaglandin
synthesis via inhibition of the activity of cyclooxygenase II (1, 21).
Intragastric administration of 100.0 mg/kg body weight (bw) of tremulacin,
a constituent of the bark, significantly inhibited carrageenaninduced
hind paw oedema in rats (p < 0.001) (22). Intragastric administration
of 0.5 ml/kg bw of a 30% ethanol extract of the bark to rats reduced
carrageenan-induced hind paw oedema, but was not effective in the adjuvant-induced
arthritis or dextran-induced pedal oedema models (23).
Antipyretic activity
Intragastric administration of 0.8 ml/kg bw of a 30% ethanol extract to
rats, suppressed yeast-induced pyrexia (23). The antipyretic effects of
salicin, saligenin (an aglycone of salicin) and salicylic acid (an active metabolite
of salicin) were assessed in rats (24). After intragastric administration
of salicin to rats, the metabolite salicylic acid appeared slowly in the
plasma and concentrations increased gradually, in contrast to the rapid
appearance observed after oral administration of sodium salicylate or saligenin.
At a dose of 5 mM/kg bw, orally administered salicin did not affect
the rectal temperature of afebrile rats while at the same dose, sodium salicylate
and saligenin lowered body temperature significantly. However,
salicin significantly reduced yeast-induced fever (p < 0.01), producing a
normal body temperature, and completely prevented fever when administered
simultaneously with yeast. Salicin did not induce gastric lesions
even at a dose of 5 mM/kg bw; conversely, sodium salicylate and saligenin
induced severe gastric lesions in a dose-dependent manner when administered
at doses of 1, 2.5 and 5 mM/kg bw (24).
Pharmacokinetics
The pharmacokinetics of salicin, saligenin (an aglycone of salicin) and
salicylic acid (an active metabolite of salicin) were determined in rats (24).
Poor absorption of salicin and rapid absorption of salicylic acid and saligenin
were confirmed in this animal model. Only small amounts of salicylic
acid and saligenin were detected in the intestinal tracts of rats 1 h
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