WHO monographs on selected medicinal plants - travolekar.ru

Ramulus cum Uncis Uncariae
tions of the pure compounds and thus the applicability of these data to
the crude drug and its preparations needs to be further investigated.
Antiarrhythmic activity
The effect of hirsutine, an indole alkaloid isolated from the crude drug, on
membrane potentials of rabbit sino-atrial node and guinea-pig right ventricle
and left atrium was investigated. Hirsutine at concentrations of
0.1–30.0 μM decreased the maximum rate of rise and prolonged action
potential duration in sino-atrial node in vitro, as well as in atrial and ventricular
preparations (18). Hirsutine, in concentrations of 1.0–3.0 μM produced
a dose-dependent relaxation of the isolated rat aorta precontracted
with either norepinephrine or potassium chloride solution, suggesting
that the compound dilated blood vessels through the inhibition of voltage-dependent
calcium channels (19). The compound, at a concentration
of 30 μM, also decreased intracellular calcium concentrations in isolated
vascular smooth muscle cells through the inhibition of norepinephrineinduced
calcium influx (20).
Anticonvulsant activity
Intragastric administration of a methanol extract of the crude drug to rats
at a dose of 1.0 g/kg body weight (bw) inhibited kainic acid-induced epileptic
seizures and reduced the levels of free radicals, as measured by lipid
peroxidation in the brain (21).
Intraperitoneal administration of an ethyl acetate or methanol extract
of the crude drug to mice at a dose of 70.0 mg/kg bw inhibited pentetrazole-induced
convulsions (22). Hyperin, a chemical constituent isolated
from the extract, decreased the elevated activities of -aminobutyric
acid-T, xanthine oxidase and lipid peroxide induced by pentetrazole
in mouse brain tissue in vitro at a concentration of 25.0 mg/ml (23).
Intragastric administration of an aqueous extract of the crude drug to
mice, at a dose of 1.0–3.0 g/kg bw, inhibited glutamate-induced convulsions,
but had no effect on convulsions induced by picrotoxin, strychnine
or electroshock (24). The active constituents of the crude drug were isolated
and identified as indole alkaloids, geissoschizine methyl ether and
hirsutine. Intragastric administration of the alkaloids to mice at a dose of
100.0 mg/kg bw also inhibited glutamate-induced convulsions in a dosedependent
manner (24).
An aqueous extract of the crude drug at a concentration of 0.1 mg/ml
prevented glutamate-induced neuronal death in cultured rat cerebellar
granule cells through the inhibition of calcium influx into the cells (25). In
cultured mouse cerebral neurons, glucose oxidase-induced toxicity was reduced
after treatment of the cells with 100 g/ml of the crude drug (26).
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