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Isoflavones and Prostate Cancer: A Review of Some Critical Issues.
Zhang, HY, Cui, J, Zhang, Y, Wang, ZL, Chong, T, Wang, ZM
Chinese medical journal. 2016;(3):341-7
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Abstract
OBJECTIVE The purpose of this review is to discuss some critical issues of isoflavones protective against the development of prostate cancer (PCa). DATA SOURCES Data cited in this review were obtained primarily from PubMed and Embase from 1975 to 2015. STUDY SELECTION Articles were selected with the search terms "isoflavone", "Phytoestrogen", "soy", "genistin", and "PCa ". RESULTS Isoflavones do not play an important role on prostate-specific antigen levels reduction in PCa patients or healthy men. The effect of isoflavones on sex hormone levels and PCa risk may be determined by equol converting bacteria in the intestine, specific polymorphic variation and concentrations of isoflavones. The intake of various types of phytoestrogens with lower concentrations in the daily diet may produce synergistic effects against PCa. Moreover, prostate tissue may concentrate isoflavones to potentially anti-carcinogenic levels. In addition, it is noteworthy that isoflavones may act as an agonist in PCa. CONCLUSIONS Isoflavones play a protective role against the development of PCa. However, careful consideration should be given when isoflavones are used in the prevention and treatment of PCa.
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Phytoestrogens and risk of prostate cancer: a meta-analysis of observational studies.
He, J, Wang, S, Zhou, M, Yu, W, Zhang, Y, He, X
World journal of surgical oncology. 2015;:231
Abstract
BACKGROUND Epidemiologic studies have reported various results relating phytoestrogens to prostate cancer (PCa). The aim of this study was to provide a comprehensive meta-analysis on the extent of the possible association between phytoestrogens (including consumption and serum concentration) and the risk of PCa. METHODS Eligible studies were retrieved via both computer searches and review of references. The summary relative risk ratio (RR) or odds ratio (OR) and 95% confidence interval (CI) were calculated with random effects models. RESULTS A total of 11 studies (2 cohort and 9 case-control studies) on phytoestrogen intake and 8 studies on serum concentration were included in the meta-analysis. The pooled odds ratio (OR) showed a significant influence of the highest phytoestrogens consumption (OR 0.80, 95% CI 0.70-0.91) and serum concentration (OR 0.83, 95% CI 0.70-0.99) on the risk of PCa. In stratified analysis, high genistein and daidzein intake and increased serum concentration of enterolactone were associated with a significant reduced risk of PCa. However, no significant associations were observed for isoflavone intake, lignans intake, or serum concentrations of genistein, daidzein, or equol. CONCLUSIONS The overall current literature suggests that phytoestrogen intake is associated with a decreased risk of PCa, especially genistein and daidzein intake. Increased serum concentration of enterolactone was also associated with a significant reduced risk of PCa. Further efforts should be made to clarify the underlying biological mechanisms.
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Analysis of the estrogenic components in kudzu root by bioassay and high performance liquid chromatography.
Zhang, Y, Chen, J, Zhang, C, Wu, W, Liang, X
The Journal of steroid biochemistry and molecular biology. 2005;(4):375-81
Abstract
The estrogenic activity of the Chinese herb kudzu root was investigated by a recombinant yeast screening assay (YES). Isoflavones are the main components in the plant, of which puerarin is the most abundant one. The kudzu root extract was separated into four fractions according to the polarity. The crude extract and its sub-fractions, except the water fraction, showed clear estrogenic activity and the potencies were in the range of 10(-3) to 10(-1)g/l. The ligand potency was used to compare the estrogenic activity of these fractions. The crude extract and its sub-fractions were further analyzed by high performance liquid chromatography (HPLC) to correlate the activity and the active components. Bioassay and chemical analysis showed that theoretical estrogenic activity expressed as equivalent 17beta-estradiol concentration or the cumulative effects are comparable to that experimentally determined by YES. The results showed that the high content of isoflavones as well as the high estrogenic activity could make kudzu root extract an interesting candidate for hormone replacement therapy.