WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
after oral administration. More than 50% of a salicin dose was recovered
as salicin and saligenin from the intestinal tracts 1 h after treatment and
15.8% of the dose was still present as saligenin 4 h after administration.
When given to germ-free rats, 19.8% of the salicin dose was recovered
intact, mainly from the cecum, and no saligenin was detected even at 4 h
after treatment. These results indicate that salicin is a pro-drug that is
gradually transported to the lower part of the intestine, hydrolysed to
saligenin by intestinal bacteria, and converted to salicylic acid after absorption.
It thus produces an antipyretic action without causing gastric
injury (25).
Toxicology
Intragastric administration of a 40% ethanol extract of the bark to rats at
a dose of 1.6 ml/kg bw for 13 weeks had no effect on kidney function,
haematological parameters, liver function or cholesterol levels (26). Histological
evaluation of the animals after killing showed no pathological
changes in the brain, heart, lungs, bone, kidneys, liver, reproductive organs,
mammary tissue, stomach or intestines (26).
The median lethal dose range of a 30% ethanol extract of the bark was
28.0–42.0 ml/kg bw in mice (both sexes) (26).
Clinical pharmacology
Anticoagulant activity
A study was performed to investigate the anticoagulant activity of a bark
extract used in the treatment of 51 patients with chronic back pain. Thirty-five
patients suffering from acute exacerbations of chronic low back
pain received randomly and double-blind either the extract (corresponding
to 240 mg salicin/day; n = 19) or a placebo (n = 16). A further 16 patients
with stable chronic ischaemic heart disease were given 100 mg acetylsalicylate
per day. Platelet aggregation was studied after drawing blood
from the treated patients using an aggregometer. Arachidonic acid (500 μg/
ml), adenosine diphosphate (2 × 10 −5 M) and collagen (0.18 μg/ml) were
used as aggregating agents. The mean maximal arachidonic acid-induced
platelet aggregation was 61%, 78% and 13% for the groups treated with
extract, placebo and acetylsalicylate, respectively. Acetylsalicylate had a
significant inhibitory effect on platelet aggregation compared to the extract
(p = 0.001) and placebo (p = 0.001). There was also a significant difference
between the placebo and the extract-treated groups in the maximal
platelet aggregation induced by arachidonic acid (p = 0.04) and ADP
(p = 0.01). No statistical difference was found between platelet aggregation
in the three groups when collagen was added to the human platelets.
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