WHO monographs on selected medicinal plants - travolekar.ru

Rhizoma Picrorhizae
Pharmacology
Experimental pharmacology
Anti-allergic and anti-asthma activity
Intragastric administration of a dose of 25.0 mg/kg body weight (bw) of a
standardized iridoid glycoside fraction from an ethanol extract of the rhizome,
inhibited passive cutaneous anaphylaxis in mice (82%) and rats
(50–85%) and protected mast cells from degranulation (60–80%) in a
concentration-dependent manner. Its effect was also studied in a sensitized
guinea-pig ileum preparation in vitro and in normal guinea-pigs in
vivo. The Schultz-Dale response was inhibited in sensitized guinea-pig
ileum, but histamine-induced bronchospasm was not antagonized or prevented
by the fraction, indicating the absence of a direct postsynaptic histamine
receptor-blocking activity (20).
A dried chloroform (0.1 mg/ml) or dried ethyl acetate extract of the
rhizome (0.01 mg/ml) inhibited histamine release in human polymorphonuclear
leukocytes treated with rabbit antihuman IgE antibody, or the calcium
ionophores A12387 or C5A in vitro (21). Intragastric administration
of a dried ethyl acetate extract of the crude drug to guinea-pigs at a dose of
10.0 mg/kg bw 1 hour prior to challenge with platelet-activating factor or
administration of ovalbumin reduced bronchial obstruction (21).
Antidiabetic activity
Intragastric administration of a dried 75% methanol extract of the rhizome
(10:1) to rats at a dose of 75.0 mg/kg bw reduced alloxan- or glucose-induced
hyperglycaemia (22). When administered at a dose of
75.0 mg/kg or 150.0 mg/kg bw, the extract also inhibited the development
of alloxan-induced diabetes, and reduced serum peroxide levels and blood
urea nitrogen concentration (22).
Antihepatotoxic activity
A standardized iridoid glycoside fraction from the rhizome exhibited significant
in vitro activity against toxicity induced by thioacetamide (200 μg/
ml), galactosamine (400 μg/ml), and carbon tetrachloride (3 μl/ml) in primary
cultured rat hepatocytes (p < 0.01). Incubation of damaged hepatocytes
with the fraction exhibited a concentration-dependent (1–100 μg/ml)
curative effect in restoring altered viability parameters (23). Intragastric
administration of a 95% ethanol extract of the crude drug to rats at a dose
of 0.75–6.0 mg/kg bw for 7 days reduced the levels of glutamate oxaloacetate
transaminase, glutamate pyruvate transaminase, acid phosphatase,
glutamate dehydrogenase and bilirubin in animals with paracetamol- or
galactosamine-induced hepatotoxicity (24, 25). The level of glycogen in
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