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WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS)
Pharmacology
Experimental pharmacology
Antihepatotoxic activity
The antihepatotoxic activity of a methanol extract of dried Herba Polygoni
avicularis was tested in rats. Intraperitoneal administration of the extract
as a single dose of 1000 mg/kg body weight (bw) (about 0.2 g per rat)
(represented as the amount of crude drug equivalent) inhibited alkaline
phosphatase, serum aspartate aminotransferase activity and decreased
plasma bilirubin concentrations when hepatotoxicity was induced
by α-naphthylisothiocyanate. At a dose of 14.7 mg/kg the extract also
inhibited serum alanine amino transaminase activity, induced by
α-naphthylisothiocyanate. The extract (200 and 500 mg/kg bw) was hepatoprotective
in conditions of carbon tetrachloride-induced hepatotoxicity.
Methanol extracts of the crude drug demonstrated hepatoprotective
effects by inhibiting lipid peroxide formation induced by adenosine diphosphate
+ nicotinamide adenine dinucleotide phosphate and carbon
tetrachloride in rats at median inhibitory concentrations (MICs) of
21.6 µg/ml and 29.1 µg/ml, respectively (56–58). Intragastric administration
of a methanol extract at a dose of 100 mg/kg bw, to male rats, reduced
serum aspartate aminotransferase and alanine amino transaminase activities
and the hydroxyproline content in the liver. In addition, the extract
significantly reduced inflammation and fibrosis of the liver in a bile duct
ligation model (59).
A free-radical scavenging effect was observed in vitro with a methanol
extract of dried Herba Polygoni avicularis at an MIC of 89 µg/plate (36,
60). Two flavonoids, avicularin and juglanin, were isolated from Herba
Polygoni avicularis as the active constituents from the ethanol-acetic fraction
by bioassay. Avicularin and, to a lesser extent, juglanin inhibited the
lipid peroxidation of rat liver induced by 50% ethanol. Avicularin, the
main constituent of the plant, significantly decreased the elevated serum
aspartate aminotransferase and lactate dehydrogenase levels in carbon
tetrachloride-intoxicated rats, demonstrating hepatoprotective properties.
Avicularin also significantly decreased the serum bilirubin level in
α-naphthylisothiocyanate-intoxicated rats. These results confirm the
hepatoprotective activity of avicularin against chemically induced hepatotoxicity
in rats (61).
The protective effects of a methanol extract of Herba Polygoni avicularis
against liver fibrosis in rats were studied in a bile duct ligation and
scission operation model, for 4 weeks. In rats that had been operated on,
the levels of aspartate aminotransferase, alanine amino transaminase, al-
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