07-01-2015, 12:12 AM
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The estrogenic activity of P. mirifica extracts evaluated by YES systems obviously varied. However, the YES assay revealed a much lower estrogenic activity of the plant extracts compared to 17β-estradiol than observed in the vaginal cornification assay (6-8). There was a difference between the two assays, i.e., there was no metabolic activation in the ordinary YES assay while metabolic activation was initiated by both intestinal microbes (29,30) and liver enzymes (31-33). Note that the results of metabolic activation of the plant samples with the S9 fraction were not in the same direction as the test without activation in which the plant extracts exhibited stronger estrogenic activity in YES-hERα + hTIF2 (Figure 4A) than in YES-hERβ + hSRC1 (Figure 2B). This demonstrates that phytoestrogens in the native form bind more strongly to ERβ than to ERα but the metabolized form may bind more strongly to ERα than to ERβ. The result was in the same direction as tested in MCF-7 cells (33).
The present data show that the P. mirifica extracts also had antiestrogenic effects at the highest dose tested of 1000 μg/mL in both YES systems. This revealed that plant samples with no estrogenic activity in the YES assay may show antiestrogenic activity in the presence of estrogen. A similar result was obtained in the previous evaluation of the estrogenic/antiestrogenic activity of a plant sample collected from Chiang Mai province when the plant extract was incubated with 17β-estradiol in a test with MCF-7 cells. The P. mirifica EtOH extract showed a significant antagonistic effect on 17β-estradiol at medium (100 µg/mL) and high (1000 µg/mL) doses (7). These two results demonstrate that antiestrogenic activity may be one of the key biological activities of P. mirifica extracts and might be related to its potential role in the prevention of breast cancer in rats (21). Previous studies have shown that isoflavones and medicinal plants have an estrogenic action and antiestrogenic activity in the in vitro tests (34).
Also, look at the graphs for which province has the highest contents.
The estrogenic activity of P. mirifica extracts evaluated by YES systems obviously varied. However, the YES assay revealed a much lower estrogenic activity of the plant extracts compared to 17β-estradiol than observed in the vaginal cornification assay (6-8). There was a difference between the two assays, i.e., there was no metabolic activation in the ordinary YES assay while metabolic activation was initiated by both intestinal microbes (29,30) and liver enzymes (31-33). Note that the results of metabolic activation of the plant samples with the S9 fraction were not in the same direction as the test without activation in which the plant extracts exhibited stronger estrogenic activity in YES-hERα + hTIF2 (Figure 4A) than in YES-hERβ + hSRC1 (Figure 2B). This demonstrates that phytoestrogens in the native form bind more strongly to ERβ than to ERα but the metabolized form may bind more strongly to ERα than to ERβ. The result was in the same direction as tested in MCF-7 cells (33).
The present data show that the P. mirifica extracts also had antiestrogenic effects at the highest dose tested of 1000 μg/mL in both YES systems. This revealed that plant samples with no estrogenic activity in the YES assay may show antiestrogenic activity in the presence of estrogen. A similar result was obtained in the previous evaluation of the estrogenic/antiestrogenic activity of a plant sample collected from Chiang Mai province when the plant extract was incubated with 17β-estradiol in a test with MCF-7 cells. The P. mirifica EtOH extract showed a significant antagonistic effect on 17β-estradiol at medium (100 µg/mL) and high (1000 µg/mL) doses (7). These two results demonstrate that antiestrogenic activity may be one of the key biological activities of P. mirifica extracts and might be related to its potential role in the prevention of breast cancer in rats (21). Previous studies have shown that isoflavones and medicinal plants have an estrogenic action and antiestrogenic activity in the in vitro tests (34).
Also, look at the graphs for which province has the highest contents.