No effect on adenoma formation in Min mice after moderate amount of flaxseed.

BACKGROUND & AIM: The mammalian lignan enterolactone (ENL) produced from plant lignans, e. g. secoisolariciresinol diglycoside (SDG), may protect against various cancers in humans. The present work aims to evaluate the effect of flaxseed on tumour formation in multiple intestinal neoplasia (Min) mice, a model for colon tumorigenesis. DESIGN: Male and female Min mice were fed either with a non-fibre control diet or the same diet supplemented with 0.5 % (w/w) defatted flaxseed meal. Conversion of SDG to the mammalian lignans enterodiol (END) and ENL in the gut, and plasma ENL, were measured by HPLC with coulometric electrode array detector (CEAD) and timeresolved fluoroimmunoassay, respectively. Wild-type mice were also fed with the experimental diets in order to see whether lignan metabolism is different in Min and wild-type mice. RESULTS: The total number of adenomas or their size in the small intestine was not different in the flaxseed and control groups. The flaxseed group had a tendency for a decreased number of colon adenomas in both genders. Gender and genotype based differences were found in the intestinal ENL levels. When compared to Min females, Min males in the flaxseed group had several fold higher ENL levels in the small intestine (Min males 125 +/- 124.5 nmol/g vs. females 22.8 +/- 16.0 nmol/g, P = 0.048) and caecum (47.6 +/- 31.6 nmol/g vs. females 14.5 +/- 6.6 nmol/g, P = 0.001). Presence of adenomas in the gut influences the intestinal lignan metabolism. Min mice had less intestinal END and ENL as compared with the wild-type mice (P < 0.05). Mean plasma ENL increased 7-fold during the flaxseed feeding (7 nmol/L in control vs. 50 nmol/L in flaxseed group) but no differences between gender and genotype were found. The plasma ENL level did not correlate with adenoma number in the small intestine and colon. CONCLUSION: The number of intestinal adenomas in the Min mouse model is not related to ENL level in plasma nor is it associated with the levels of intestinal lignans. A gender difference in ENL lignan metabolism was found in the gut but not in the plasma.

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.

In vitro metabolism of plant lignans: new precursors of mammalian lignans enterolactone and enterodiol.

The metabolism of the plant lignans matairesinol, secoisolariciresinol, pinoresinol, syringaresinol, arctigenin, 7-hydroxymatairesinol, isolariciresinol, and lariciresinol by human fecal microflora was investigated to study their properties as mammalian lignan precursors. The quantitative analyses of lignan precursors and the mammalian lignans enterolactone and enterodiol were performed by HPLC with coulometric electrode array detector. The metabolic products, including mammalian lignans, were characterized as trimethylsilyl derivatives by gas chromatography-mass spectrometry. Matairesinol, secoisolariciresinol, lariciresinol, and pinoresinol were converted to mammalian lignans only. Several metabolites were isolated and tentatively identified as for syringaresinol and arctigenin in addition to the mammalian lignans. Metabolites of 7-hydroxymatairesinol were characterized as enterolactone and 7-hydroxyenterolactone by comparison with authentic reference compounds. A metabolic scheme describing the conversion of the most abundant new mammalian lignan precursors, pinoresinol and lariciresinol, is presented.

Sensitive high-performance liquid chromatographic method for profiling phytoestrogens using coulometric electrode array detection: application to plasma analysis.

An HPLC method for profiling 13 phytoestrogens and their metabolites using coulometric electrode array detection was developed. Sensitivity of the method was slightly less than that of our GC-MS method, but significantly higher compared to the HPLC methods using diode-array or UV detection. Detection limits varied from 3.4 (secoisolariciresinol) to 40.3 (genistin) pg on column. Signal linearities ranged from the detection limits to 61 ng on column. Resolution values for the peak pairs varied from 1.1 (O-desmethylangolensin-anhydrosecoisolariciresinol) to 16 (daidzin-genistin). Intra- and interassay retention time variations were negligible and detector response variation was eliminated by frequent calibration. Chromatographic method was applied to plasma analyses and 6 of the 13 compounds were detected. Method accuracy for those six analytes varied from 69% (enterodiol) to 118% (genistein). Intraassay precision CVs ranged from 1.5% (enterolactone, 12.4 nmol/liter) to 14% (genistein, 245 nmol/liter) and interassay precision CVs ranged from 9.9% (daidzein, 67.4 nmol/liter) to 44% (enterodiol, 1.20 nmol/liter).

Serum iron, copper, zinc, ferritin, and ceruloplasmin after intense heat exposure.

Twelve voluntary adult subjects twice took a 30-min sauna bath, at a temperature of 80 degrees C with a 30-min rest between each, every 12 h for 1 week. Measurements of serum iron, copper, zinc, ferritin and ceruloplasmin were performed before the experiment, after the first and second 30 min in the sauna and at the end of the week. The first two sauna baths did not significantly change the concentrations of the trace elements measured. After the week the mean serum copper concentration had decreased from 15.0 (SD 1.7) mumol x 1-1 to 13.5 (SD 2.0) mumol x 1-1 (p less than 0.02). The mean zinc concentration decreased from 13.8 (SD 2.4) mumol x 1-1 to 9.8 (SD 1.8) mumol x 1-1 (p less than 0.001) during the week of the experiment. At the beginning of the study period two subjects had zinc concentrations below the reference values and after the week nine subjects had zinc concentrations below the reference values. The concentration of serum ferritin decreased from 142.2 (SD 103) micrograms x 1-1 to 111.3 (SD 89) micrograms x 1-1 (p less than 0.02) whereas the values of ceruloplasmin remained unchanged. Our findings confirm the earlier suggestion that heavy exposure to heat can cause a loss of some trace elements, especially zinc.

Acute phase proteins, humoral and cell mediated immunity in environmentally-induced hyperthermia in man.

The effects of repeated hyperthermia, caused by a Finnish sauna bath over 1 week, on the serum levels of some acute phase reactant proteins and on both humoral and cell-mediated immunity on twelve healthy young volunteers are presented. The mean rise in rectal temperature during each 30-min period in the bath was about 1.3 degrees C. Heat exposure caused significant increases in the serum concentrations of two of the acute phase reactant proteins, alpha1-antitrypsin (from a mean value of 1.8 (0.1) to 1.9 (0.2) g X l-1, p less than 0.01) and transferrin (from a mean value of 36.9 (3.4) to 38.3 (4.4) mumol X l-1, p less than 0.05), but no changes occurred in immunoglobulins or cell-mediated immunity. These findings suggest that environmentally induced hyperthermia can initiate the acute phase reaction associated with fever.