WHO monographs on selected medicinal plants - travolekar.ru

<strong>WHO</strong> <strong>monographs</strong> on selected medicinal plants
(Ox-LDL) to impair endothelium-dependent relaxation in rat aortic rings
was specifically assessed. Native LDL (0.2 or 0.3 mg/ml) was incubated
with the saponins (0.25–1.0 mg/ml), with vitamin C (50 μM) as a control.
Oxidation was initiated with copper sulfate at 37 ºC for 0–24 h. The results
demonstrate that the saponins reduced lipid peroxide levels concentrationdependently
and also reduced alterations in relative electrophoretic mobility
of Ox-LDL in a similar manner. Furthermore, measurement of content
of phospholipid fractions indicated that the saponins reduced the conversion
of phosphatidylcholine to lysophosphatidylcholine in Ox-LDL (27).
Further investigations indicated that lower concentrations of saponins
(1.0–100.0 μg/ml) in combination with vitamin C (1.0–10.0 μM) significantly
enhanced the protective effects of the saponins. Pretreatment with
the saponins (1.0–100.0 μg/ml) resulted in concentration-dependent inhibition
of LDL oxidation and prolongation of lag time (28).
Antithrombotic activity
The effects of a root extract on thrombin-induced endothelin release were
investigated using cultured human umbilical vein endothelial cells. Endothelial
cells were pretreated with 1, 10 and 100.0 μg/ml of the extract
and then incubated for 4 and 24 h with thrombin. The results demonstrated
that the concentration of endothelin was significantly decreased in
a concentration-dependent, time-related manner (at 4 h, 50% inhibitory
concentration (IC 50
) = 5.1 μg/ml; at 24 h, IC 50
= 6.2 μg/ml). Furthermore,
pretreatment of cultured endothelial cells with NG-nitro-L-arginine, a
nitric oxide synthetase inhibitor, significantly (p < 0.05) inhibited thrombin-induced
endothelin release by the extract indicating that the effect
was partly due to release of nitric oxide (29).
Hormonal activity
A methanol extract of the root (100 g root in methanol 600 ml) did not
significantly bind to either estrogen receptor or at a concentration of
20.0 μg/ml, but did increase expression of pS2 (an estrogen-sensitive gene)
in S-20 cells (30).
The expression of the estrogen-regulated gene pS2 in MCF-7 breast
cancer cells was assessed after treatment of the cells with a decoction of
the roots. The extract and estradiol were equally able to induce RNA expression
of pS2, and the extract caused a dose-dependent decrease in cell
proliferation (p < 0.005) (31). The estrogenic effects of a decoction of the
roots on the expression of pS2, an estrogen-regulated gene, in breast cancer
cell lines MCF-7, T-47D and BT-20 was evaluated by Northern and
Western blot analyses. Competitive studies were also performed with ginseng
in combination with tamoxifen. The ginseng extract (600.0 μg) and
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