WHO monographs on selected medicinal plants - travolekar.ru

Lichen Islandicus
(16)-linked -D-mannopyranosyl and -D-(16)-galactopyranosyl
units, had pronounced immunostimulating activity. The polysaccharide
enhanced granulocytic phagocytosis by 68%, when administered at a
concentration of 1 mg/ml, in human granulocytes in vitro. Intraperitoneal
administration of the polysaccharide to mice, at a dose of 1.0 mg/kg
body weight (bw), increased the rate of carbon clearance, indicating significant
activation of the reticuloendothelial system (13, 25, 26). A polysaccharide
named Ci-3, isolated from an aqueous extract of the thalli, as
well as from an alkali extract of the thalli had immune stimulating activity
in vitro. At a concentration of 100.0 μg/ml, the polysaccharide Ci-3 stimulated
granulocytic phagocytosis and reduced the complement-induced
haemolysis in sheep erythrocytes by 80% (27).
Toxicity
Lichens are known to naturally contain bitter and potentially toxic lichen
acids, as well as concentrated heavy metals that are taken up from the
environment. The toxicity of the thalli was investigated using traditional
preparation methods (boiling, ash-soaking). Untreated and briefly boiled
thalli were lethal to mice when added to feed at concentrations of 25 and
50% w/w, but when the thalli were prepared by ash-soaking, the mice
tolerated the crude drug reasonably well for 3 weeks (28).
In another study, the toxicity of the traditionally prepared thalli was assessed
in mice and rats. As a 50% w/w mixture in normal feed neither the
pretreated nor the untreated thalli additive was well tolerated by mice.
However, rats tolerated 25% w/w ash-treated thalli in normal feed over
3 months, although the body weight did not increase as much as in control
animals. At the end of the experiment, the rats in the thalli-treated group
had proteinuria, and on autopsy some tubular changes were found, probably
due to high concentrations of lead in the thalli and in the kidneys (29).
Clinical pharmacology
In an open clinical trial, 100 patients (children and adults) suffering from
inflammatory irritative conditions of the respiratory tract were treated
with lozenges containing an aqueous extract of the thalli. The illnesses
ranged from pharyngitis and laryngitis to chronic or acute bronchitis. The
patients were treated with lozenges containing 160.0 mg of an aqueous
extract of the crude drug, for between 4 days and 3 weeks. After evaluation
of the symptoms such as cough, hoarseness, secretion, inflammation and
pain, a positive outcome was observed in 86% of patients. The lozenges
were well tolerated, with few side-effects and good gastric tolerance (16).
Sixty-one patients who had recently undergone surgery to the nasal
septum were included in a randomized, placebo-controlled, clinical trial.
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