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Herba Polygoni avicularis
kaline phosphatase, total bilirubin in serum and hydroxyproline content
in liver were dramatically increased. Treatment with the extract in rats
that had been operated on reduced the serum aspartate aminotransferase,
alanine amino transaminase and alkaline phosphatase levels significantly
(p < 0.01). Liver hydroxyproline content was also reduced to 40% by
treatment with the extract as compared with controls (p < 0.01). The
morphological characteristics of fibrotic liver, which appeared in the
control group of animals that had been operated on were less marked in
the group that had been both operated on and treated with the extract.
These results suggest that Herba Polygoni avicularis has an antifibrotic
effect in rats (59).
Antiaggregatory effects
The antiaggregatory effects of vitexin, isovitexin, luteolin, kaempferol-3-
arabinoside, rhamnetin-3-galactoside and quercetin-3-galactoside, active
constituents isolated from Herba Polygoni avicularis, were tested in vitro,
in platelet-rich plasma from blood donors. It was shown that vitexin and
rhamnetin-3-galactoside, at a concentration of 10 -5 M, inhibited the aggregation
of human blood platelets induced by adenosine diphosphate
(concentration 10 -5 M) and arachidonic acid (concentration 10 -4 M),
whereas luteolin and kaempferol-3- arabinoside slowed or stimulated aggregation,
depending upon the experimental conditions. These findings
suggest that constituents tested may influence platelet aggregation by
possible interaction with the cyclooxygenase and lipoxygenase pathway
of the arachidonic acid cascade in human platelets (62, 63).
Angiotensin-converting enzyme inhibiting activity
A chromatographic fraction from Herba Polygoni avicularis, containing
rhatannin and other tannins, at a concentration of 20 µg/ml, and a methanol-aqueous
extract (1:1) at a concentration of 200 µg/ml, inhibited the
activity of angiotensin-converting enzyme isolated from pig kidney in
vitro. Both rhatannin and the tannin samples had potent inhibitory effects
on angiotensin-converting enzyme with an MIC of 1.1 mg/ml and showed
high specificity for this enzyme (64, 65).
Anti-inflammatory effects
An aqueous extract of oven-dried Herba Polygoni avicularis (at a concentration
of 0.25 mg/ml) inhibited platelet activating factor in cell culture
and platelet activating factor-induced neutrophil exocytosis. These findings
may suggest a mechanism for the antiinflammatory action of the
plant (66).
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