WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
Immune stimulatory effects
A dried diethyl ether extract of the rhizome inhibited the classical pathway
of complement (median inhibitory concentration (IC 50
) 1.9 μg/ml).
Aqueous, petroleum ether, methanol or ethyl acetate extracts of the crude
drug had inhibitory concentrations of 13, 17, 38 and 55 μg/ml, respectively
(3). The diethyl ether extract of the crude drug also had moderate
inhibitory activity against the activation of polymorphonuclear cells (IC 50
53 μg/ml) in vitro, and reduced mitogen-induced proliferation of T lymphocytes
(IC 50
13 μg/ml) (3). Two cucurbitacins, picracin and deacetylpicracin,
isolated from the rhizomes of the crude drug were responsible
for the inhibition of mitogen-induced human T-lymphocyte proliferation
(39). Incubation of picracin and deacetylpicracin with peripheral blood
lymphocytes inhibited interleukin-2 release by phytohaemagglutininactivated
T cells. The IC 50
s were 5 and 16 μM, respectively. Both picracin
and cucurbitacin E also inhibited the release of interleukin 1 and tumour
necrosis factor from monocytes (IC 50
s were 15 and 3 μM, respectively).
Deacetylpicracin was not active at concentrations up to 100 μM (40).
Intraperitoneal injection of picracin or deacetylpicracin, 1 hour prior to
induction of delayed-type hypersensitivity significantly (p < 0.001) inhibited
the delayed-type hypersensitivity response at doses of 100.0 mg/
kg and 30.0 mg/kg bw in mice (41).
Toxicology
An aqueous ethanol extract of the rhizome administered intraperitoneally
to mice had a median lethal dose of 1.09 g/kg bw, indicating low toxicity
(38). A 70% methanol extract of the crude drug administered intragastrically
to mice exhibited a median lethal dose at > 2 g/kg bw (41). An aqueous
extract of the rhizome did not stimulate cell proliferation in melanocyte
cells in vitro at a concentration of 1 mg/ml (42). The median lethal
dose of cucurbitacin B was 0.5 mg/kg bw in rabbits after intravenous administration
and 340 mg/kg bw of cucurbitacin E in mice after oral administration
(3). Oral administration of 200 mg/kg bw of an ethanol or diethyl
ether extract of the crude drug for 3 or 6 weeks did not increase the weight
of the thymus, spleen, liver or mesenterial lymph nodes in mice (3).
Clinical pharmacology
In one therapeutic observational study, 20 patients with bronchial asthma
were treated with a crude extract of the drug (300 mg three times daily)
for 1 year. Outcomes measured included clinical improvement, reduction
in the use of bronchodilators and pulmonary function tests. Of the 20 patients
treated, 10 showed varying degrees of clinical improvement, including
an improvement in pulmonary function tests (17).
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