Isoflavone content of the soy based supplements.

A large number of soy isoflavone products with indications of possible health effects are available on the market. Fifteen different soy based products were analyzed using high performance liquid chromatography (HPLC) with coulometric electrode array detector to determine the total amount of isoflavones in aglycones after the hydrolysis and identify the different forms of the isoflavone conjugates. The aim of the study was to evaluate how well the isoflavone content data supplied by the producers correspond to our analysis results. Only one product contained isoflavones measured in aglycones the same amount as was the value given by the producer. The total amount of the isoflavones in aglycones ranged from 0.121 to 201 mg/g. Measured amounts of isoflavones in aglycones after the hydrolysis were in general lower than the values in the product labels. Product data were often confusing and the concrete amount of isoflavones was difficult to find out.

Intake of dietary phytoestrogens is low in postmenopausal women in the United States: the Framingham study(1-4).

Many plants that are consumed contain phytoestrogens. Only a few published studies have examined the dietary intake of phytoestrogens in the general Western population. The potentially positive health effects of phytoestrogens might be of relevance to postmenopausal women. The aim of the present study was to estimate the intake of dietary isoflavones, coumestans and lignans by healthy Western postmenopausal women. For this purpose, we studied 964 postmenopausal, Caucasian women who participated in the Framingham Offspring Study and completed the Willett food-frequency questionnaire (FFQ). By searching the medical and agricultural literature and contacting experts, we identified food sources of phytoestrogens. The concentrations of the different isoflavones, coumestrol and lignans in each food in the FFQ were scored in seven categories and multiplied by the serving size of the food and the frequency of its consumption. The estimated daily median intake of the isoflavone daidzein was 39 microg (24-57 microg); of genistein, 70 microg (28-120 microg); of formononetin, 31 microg (13-44 microg); and of biochanin A, 6 microg (2-11 microg). Median total intake of isoflavones was 154 microg (99-235 microg). The main sources of isoflavones were beans and peas. The estimated daily intake of coumestans was 0.6 microg (0.2-1.7 microg), with broccoli as the main source. The estimated daily median intake of matairesinol was 19 microg (12-28 microg) and of secoisolariciresinol 560 microg (399-778 microg). The median total intake of lignans was 578 microg (416-796 microg). The main source of the lignans was fruits. The daily dietary intake of phytoestrogens in healthy postmenopausal Caucasian women in the United States is <1 mg.

Positive and negative strands of HCV-RNA in sera and peripheral blood mononuclear cells of chronically hemodialyzed patients.

BACKGROUND: Hepatitis C virus (HCV) RNA can be detected in sera and peripheral blood mononuclear cells (PBMC) of patients undergoing chronic hemodialysis. However, the natural course of HCV infection in this group of patients is not fully known. Although the exact mechanism of HCV replication is not completely explained, there is evidence that HCV replicate through synthesis of complementary negative (-) RNA strand, whereas positive (+) RNA strand serves as a template. Thus, the detection of negative HCV-RNA strand can be regarded as a marker of ongoing viral replication. MATERIAL AND METHODS: We investigated the prevalence of (+) and (-) strands of HCV-RNAs in sera and PBMC of 45 chronically hemodialyzed patients using PCR methods. We also determined HCV genotypes and their subtypes by Inno-LIPA method. RESULTS: Eight (17.8%) of analyzed patients were anti-HCV positive. In this group, we detected HCV-RNA (+) strands in sera and PBMC in 2 and 4 cases respectively, whereas HCV-RNA (-) ones were found in PBMC of 4 patients. Among the remaining 37 anti-HCV negative patients we found HCV-RNA positive strands in sera and PBMC in 2 and 3 cases respectively, whereas HCV-RNA negative strand was present in PBMC in one of them. CONCLUSIONS: Our results indicate that HCV actively replicate in PBMC in chronically hemodialyzed patients. In number of patients HCV-RNAs can be detected only in PBMC without concomitant presence of viremia or anti-HCV in sera. We did not find any correlation between genotypes of HCV and presence of HCV-RNAs strands in PBMC of the patients.

Synthesis of deuterated plant lignans for gas chromatography-mass spectrometry analysis.

Stabile deuterated plant lignans D(6)-matairesinol, D(8)-secoisolariciresinol, and D(8)-anhydrosecoisolariciresinol are synthesized to be used as internal standards in isotope dilution technique of gas chromatography-mass spectrometry in the selected ion monitoring mode.

Lignan and isoflavonoid concentrations in tea and coffee.

Tea is a beverage consumed widely throughout the world. The existence in tea of chemopreventing compounds possessing antimutagenic, anticarcinogenic and antioxidative properties has been reported. High intakes of tea and foods containing flavonoids have recently been shown to be negatively correlated to the occurrence of CHD. However, tea may contain other compounds with similar activities. Using a new gas chromatographic-mass spectrometric method we measured lignans and isoflavonoids in samples of twenty commercial teas (black, green and red varieties) and, for comparison, six coffees. Both unbrewed and brewed tea were investigated. The analysis of the teas yielded relatively high levels of the lignans secoisolariciresinol (5.6-28.9 mg/kg; 15.9-81.9 mumol/kg) and matairesinol (0.56-4.13 mg/kg; 1.6-11.5 mumol/kg) but only low levels of isoflavonoids. Because the plant lignans, as well as their mammalian metabolites enterolactone and enterodiol, have antioxidative properties and these mammalian lignans occur in high concentrations in plasma, we hypothesize that lignan polyphenols may contribute to the protective effect of tea on CHD.

Phytoestrogen content in foods.

Plants abound in essential phytochemicals produced for their various vital functions. The same compounds seem also to be crucial for human health and disease. Recent human epidemiological and laboratory animal and cell studies on cancer and heart disease have highlighted the phytoestrogens--naturally occurring principles that share with steroidal oestrogens an ability to activate oestrogen receptors. The best known non-steroidal phytoestrogens include the isoflavones daidzein, genistein, formononetin and biochanin A, the coumestan coumestrol, and the lignans secoisolariciresinol and matairesinol. Acknowledging the potentially chemoprotective role of these non-nutrients, we have quantified all biologically important isoflavonoids and lignans in cereals, oilseeds and nuts, legumes, vegetables, fruits, berries and beverages such as tea, coffee and wine. In this chapter, we present a review of our studies on staple plant foods, indicating that plants contain, besides a wide range of chemicals with a number of biological properties, biologically active phytoestrogens--precursors of hormone-like compounds found in mammalian systems.