The Association between Plasma Concentration of Phytoestrogens and Hypertension within the Korean Multicenter Cancer Cohort.

In order to examine the association between plasma phytoestrogen concentration (genistein, daidzein, equol and enterolactone) and hypertension, we conducted a nested case-control study for 229 hypertension cases including 112 prehypertension and 159 healthy controls derived from the Korean Multi-center Cancer Cohort (KMCC). The concentration of plasma phytoestrogens was measured using time-resolved fluoroimmunoassay. We assessed the association between plasma phytoestrogens and hypertension using logistic regression models using odds ratio (OR) and 95% confidence interval (95%CI). The highest tertile of plasma equol and enterolactone concentration exhibited a significantly decreased risk of hypertension (equol, OR = 0.34, 95%CI 0.20-0.57; enterolactone, OR = 0.32, 95%CI 0.18-0.57), compared with the lowest tertile. Equol and enterolactone showed reduced ORs for prehypertension (the highest tertile relative to the lowest tertile, OR = 0.50, 95%CI 0.26-0.96; OR = 0.38, 95%CI 0.19-0.75, respectively) and hypertension (OR = 0.42, 95%CI 0.22-0.81; OR = 0.28, 95%CI 0.14-0.54, respectively). There was a stronger association in hypertension (the highest tertile relative to the lowest tertile in obesity vs. non-obesity; equol, OR = 0.06 vs. 0.63; enterolactone, OR = 0.07 vs. 0.46; both p-heterogeneity < 0.01). This study suggests that equol and enterolactone may contribute to prevent primarily prehypertension and hypertension, and control cardiovascular disease (CVD) based on the continuum of hypertension and CVD. Further study to assess hypertension risk based on useful biomarkers, including phytoestrogens, may contribute to primary prevention of hypertension.

Dietary phytoestrogens and biomarkers of their intake in relation to cancer survival and recurrence: a comprehensive systematic review with meta-analysis.

CONTEXT: Recent studies have outlined the potential role of dietary factors in patients who have survived cancer. OBJECTIVE: The aim of this study was to summarize the evidence of the relation between dietary intake of phytoestrogens and their blood biomarkers and, overall, cancer-specific mortality and recurrence in patients with cancer. DATA SOURCES: A systematic search of PubMed, EMBASE, and Web of Science databases of studies published up to September 2019 was performed. Databases were searched for prospective and retrospective cohort studies reporting on dietary phytoestrogen intake and/or blood biomarkers and the outcomes investigated. DATA EXTRACTION: Data were extracted from each identified study using a standardized form. DATA ANALYSIS: Twenty-eight articles on breast, lung, prostate, and colorectal cancer, and glioma were included for systematic review. Given the availability of studies, a quantitative meta-analysis was performed solely for breast cancer outcomes. A significant inverse association among higher dietary isoflavone intake, higher serum/plasma enterolactone concentrations, and overall mortality and cancer recurrence was found. Among other cancer types, 2 studies reported that higher serum enterolactone and higher intake of lignans were associated with cancer-specific survival for colorectal cancer and glioma, respectively. CONCLUSIONS: Dietary phytoestrogens may play a role in survival from breast cancer ; evidence regarding other cancers is too limited to draw any conclusions.

Prognostic associations of circulating phytoestrogens and biomarker changes in long-term survivors of postmenopausal breast cancer.

Lignans are associated with improved postmenopausal breast cancer (BC) survival, but whether these associations, particularly with enterolactone (major lignan metabolite), persist over time is unclear. Little is known about other phytoestrogens on prognosis in long-term survivors. The study examines associations of prognosis with 1) circulating postdiagnosis enterolactone, 2) eight circulating phytoestrogen metabolites, and 3) changes in enterolactone and genistein. In a German cohort of 2,105 postmenopausal BC patients with blood samples collected at recruitment 2002-2005 (baseline) and re-interview in 2009 (follow-up), delay-entry Cox proportional hazards regression was used. Landmark analysis showed that circulating enterolactone (log2) associations with 5-year survival changed over time, with strongest hazard ratios of 0.89 (95% CI, 0.80-0.99) at blood draw (BD) and 0.86 (0.77-0.97) at 2 years post-BD for BC mortality, and 0.87 (0.80-0.95) at BD and 0.84 (0.76-0.92) at 3 years post-BD for all-cause mortality, which attenuated thereafter. In long-term survivors, increasing concentrations of genistein (1.17, 1.01-1.36), resveratrol (1.19, 1.02-1.40), and luteolin (1.96, 1.07-3.58) measured in follow-up blood samples were associated with poorer subsequent prognosis. Neither enterolactone at follow-up nor changes in enterolactone/genistein were associated with prognosis. Large long-term longitudinal studies with multiple phytoestrogen measurements are required to understand long-term effects of phytoestrogens after BC.

Simultaneous quantification of ligustilide, dl-3-n-butylphthalide and senkyunolide A in rat plasma by GC-MS and its application to comparative pharmacokinetic studies of Rhizoma Chuanxiong extract alone and Baizhi Chuanxiong Decoction.

The herb couple has special clinical significance in reducing the toxicity and increasing the efficacy of drugs. The combination of Radix Angelicae Dahuricae (Baizhi, BZ) and Rhizoma Chuanxiong (ChuanXiong, CX) is a traditional herb couple. The combination performs better than the CX extract alone in the treatment of migraine and has been used for thousands of years. However, the specific compatibility mechanisms are still unclear. Ligustilide, dl-3-n-butylphthalide and senkyunolide A are the major active ingredients in CX and BZ-CX decoction. However, a comprehensive study of the pharmacokinetics of CX has not been carried out. A gas chromatography-mass spectroscopy (GC-MS) method with high selectivity, sensitivity and accuracy was developed. An SH-Rxi-5Sil (30 m × 0.25 mm i.d., and 0.25 µm film thickness) column was employed in the GC separation. Selectivity, linearity, precision, accuracy, recovery, matrix effect and stability were used to validate the current GC-MS method. Using the validated method, this is the first time to study on the comparative pharmacokinetics of ligustilide, dl-3-n-butylphthalide and senkyunolide A from CX alone and BZ-CX decoction in rat plasma. The pharmacokinetic parameters (Cmax , Tmax , T1/2 , AUC0-t , AUC0-∞ and CLz/F) of all of the detected ingredients showed significant differences between the two groups (P < 0.05). The results are helpful for further investigation of the compatibility mechanism of BZ-CX decoction.

Plasma phytoestrogens concentration and risk of colorectal cancer in two different Asian populations.

BACKGROUND & AIMS: To evaluate the relationship between phytoestrogen and colon cancer risk, we quantified plasma isoflavones (Genistein and Daidzein) and lignan (enterolactone) in a Korean nested case-control study and conducted replication study in a Vietnamese case-control study. METHODS: Study populations of 101 cases and 391 controls were selected from the Korean Multicenter Cancer Cohort which was constructed from 1993 to 2004. For replication study, Vietnamese hospital-based case-control subjects of 222 cases and 206 controls were selected from 2003 to 2007. The concentrations of plasma genistein, daidzein, and enterolactone were quantified by liquid chromatography-mass spectrometry. Logistic regression models were used to compute odds ratios (ORs) and 95% confidence intervals (CIs), and meta-analysis was conducted to estimate combined ORs (CORs) and 95% Cis of Korean and Vietnamese population in 2014. RESULTS: Genistein showed a continual decrease in colorectal cancer risk according to level up of the concentration categories in Korean and Vietnamese population (P for trend = 0.032, and 0.001, respectively) and a significantly decreased risk was found at the highest concentration of genistein and daidzein (for the highest category compared to the lowest: COR (95% CI) = 0.46 (0.30-0.69), and COR (95% CI) = 0.54 (0.36-0.82)). When the study population was stratified, the beneficial relationship of genistein with colorectal cancer was observed regardless of sex and anatomical subtype. However, enterolacton level was not associated with colorectal cancer risk. CONCLUSIONS: High plasma levels of isoflavones had relationship with a decreased risk of colorectal cancer, regardless of different ethnic background.

Pre-diagnostic plasma enterolactone concentrations and breast cancer prognosis among postmenopausal women - The Danish Diet, Cancer and Health cohort.

BACKGROUND & AIMS: High intakes of the phytoestrogen lignans and high blood concentrations of its main biomarker, enterolactone, has been associated with a better breast cancer prognosis. We investigated the association between pre-diagnostic plasma concentrations of enterolactone and breast cancer prognosis (i.e. recurrence, breast cancer-specific mortality and all-cause mortality). METHODS: Plasma and data was available from the Danish Diet, Cancer and Health cohort. Information on treatment and clinical characteristics from registries and clinical databases and both pre-diagnostic and diagnostic plasma measurement of enterolactone on a sub-set. Enterolactone was quantified in plasma using a high-throughput LC-MS/MS method. We followed 1457 breast cancer cases from date of diagnosis and until censoring or end-of-follow-up (median 9 years), during this time 404 died (250 of breast cancer) and 267 experienced recurrence. Cox proportional hazards models were used to estimate hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: Plasma enterolactone were borderline significantly associated with lower breast cancer-specific mortality (HRdoubling = 0.93, 95% CI:0.86, 1.00, P = 0.0501), but not associated with all-cause mortality (HRdoubling = 0.95, 95% CI:0.89, 1.01) and recurrence (HRdoubling = 0.96, 95% CI: 0.89, 1.04) in the models adjusted for smoking, schooling, BMI, physical activity and use of menopausal hormones. Adjusting further for clinical characteristics and treatment did not change the results considerably. In the sensitivity analyses, an inverse association was found with all-cause and breast cancer-specific mortality for those where blood was collected ≤5 years before diagnosis. CONCLUSIONS: Overall, no clear association was found between pre-diagnostic plasma concentrations of enterolactone and breast cancer prognosis.

Plasma firocoxib concentrations after intra-articular injection of autologous conditioned serum prepared from firocoxib positive horses.

Orthobiologics such as autologous conditioned serum (ACS) are often used to treat joint disease in horses. Because ACS is generated from the horse's own blood, any medication administered at the time of preparation would likely be present in stored ACS, which could lead to an inadvertent positive drug test following intra-articular (IA) injection. The main objective of this study was to determine if ACS prepared from firocoxib positive horses could result in detectable plasma concentrations of the drug following IA injection. Firocoxib was administered to six horses at 0.1mg/kg PO twice at a 24h interval. Blood was obtained at 4h following the second dose and transferred to a separate syringe (Arthrex IRAP II) for ACS preparation. Plasma and ACS concentrations of firocoxib were analysed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). When horses were confirmed firocoxib negative, 7.5mL of ACS was injected into both tarsocrural joints. Blood samples were collected at 0, 4, 8, 12, 24, and 48h, and firocoxib concentration was measured. Mean (±standard error of the mean, SEM) plasma concentration of firocoxib 4h following the second dose was 33.3±4.72ng/mL. Mean (±SEM) firocoxib concentration in ACS was 35.4±4.47ng/mL. Fourteen days following the second and last dose of firocoxib, mean plasma concentration was below the lower limit of detection (LOD=1ng/mL) in all horses. Following IA injection of ACS, plasma concentrations of firocoxib remained below LOD at all times in all horses. ACS generated from horses with therapeutic plasma concentrations of firocoxib did not contain sufficient firocoxib to lead to a positive plasma drug test following IA administration.

Plasma metabolite abundances are associated with urinary enterolactone excretion in healthy participants on controlled diets.

Enterolignans, products of gut bacterial metabolism of plant lignans, have been associated with reduced risk of chronic diseases, but their association with other plasma metabolites is unknown. We examined plasma metabolite profiles according to urinary enterolignan excretion in a cross-sectional analysis using data from a randomized crossover, controlled feeding study. Eighty healthy adult males and females completed two 28-day feeding periods differing by glycemic load, refined carbohydrate, and fiber content. Lignan intake was calculated from food records using a polyphenol database. Targeted metabolomics was performed by LC-MS on plasma from fasting blood samples collected at the end of each feeding period. Enterolactone (ENL) and enterodiol, were measured in 24 h urine samples collected on the penultimate day of each study period using GC-MS. Linear mixed models were used to test the association between enterolignan excretion and metabolite abundances. Pathway analyses were conducted using the Global Test. Benjamini-Hochberg false discovery rate (FDR) was used to control for multiple testing. Of the metabolites assayed, 121 were detected in all samples. ENL excretion was associated positively with plasma hippuric acid and melatonin, and inversely with epinephrine, creatine, glycochenodeoxycholate, and glyceraldehyde (P < 0.05). Hippuric acid only satisfied the FDR of q < 0.1. END excretion was associated with myristic acid and glycine (q < 0.5). Two of 57 pathways tested were associated significantly with ENL, ubiquinone and terpenoid-quinone biosynthesis, and inositol phosphate metabolism. These results suggest a potential role for ENL or ENL-metabolizing gut bacteria in regulating plasma metabolites.

Genistein and enterolactone in relation to Ki-67 expression and HER2 status in postmenopausal breast cancer patients.

SCOPE: Phytoestrogens (PE) may improve breast cancer prognosis by modifying tumor prognostic markers, such as cell proliferation marker Ki-67 and human epidermal growth factor receptor 2 (HER2). Epidemiological evidence linking lignans and isoflavones to Ki-67 and HER2 is limited. We examined associations between the major metabolites of lignans and isoflavones - enterolactone (ENL) and genistein (GEN) - respectively, and Ki-67 expression and HER2 in tumor tissue of breast cancer patients. METHODS AND RESULTS: Data from 1060 invasive breast cancer patients from the population-based MARIE study were used. Multivariate-adjusted linear (Ki-67 log-transformed) and quantile regression, and logistic regression analyses (HER2, Ki-67 dichotomized) were performed to calculate ß estimates and ORs, respectively. Median post-diagnostic ENL and GEN concentrations were 19.5 and 4.8 nmol/L, respectively. Median Ki-67 was 12.0%, and 21.2% of the tumors were HER2+. After adjustment, there was an inverse association between GEN and Ki-67 at high expression levels (OR for Ki-67 ≥20% versus <20% of 0.93 (95%CI [0.87;0.99]) per 10 nmol/L GEN increment). CONCLUSION: Our findings indicate an inverse association between GEN and Ki-67 at high levels of Ki-67 expression. Additional investigations are recommended to confirm our findings and to further elucidate mechanisms linking PE metabolites to breast cancer survival.

Short communication: Concentrations of the mammalian lignan enterolactone in preovulatory follicles and the correlation with intrafollicular estradiol in dairy cows fed extruded flaxseed.

Flaxseed is a rich source of lignans that can be metabolized to the mammalian lignan enterolactone (EL), which may elicit weak estrogenic or antiestrogenic effects. The objectives of this study were to examine the effects of feeding an extruded flaxseed supplement to dairy cows on concentrations of EL in plasma and preovulatory follicles and the association with intrafollicular estradiol (E2). Twenty-four multiparous 256-d-pregnant Israeli Holstein cows were fed either a standard diet both pre- and postpartum (control; n=12) or provided with an extruded flaxseed supplement (n=12), at 7.9 and 9.2% of dry matter, pre- and postpartum, respectively. Follicular fluid (FF) aspirations were conducted at 84±16 d in lactation as follows: 7 to 8 d following behavioral estrus, cows were injected with prostaglandin F2α and 48h later follicles >7mm were aspirated. Follicles were regarded as preovulatory when the E2-to-progesterone ratio was >1. Plasma EL concentrations were not different between treatment groups; however, concentrations of EL in FF of preovulatory follicles were 1.7 times higher in extruded flaxseed-supplemented cows than in control. Across-treatment analysis revealed a positive correlation between concentrations of EL in plasma and in FF. In addition, intrafollicular EL concentrations were positively correlated with E2 concentrations (r=0.50), and with the intrafollicular E2-to-progesterone ratio. In conclusion, supplementing dairy cows with extruded flaxseed increased EL concentrations in preovulatory follicles. Intrafollicular EL was correlated with E2 concentrations; therefore, the possible effects of EL from flaxseed on follicular steroidogenesis should be considered.

Flaxseed reduces the pro-carcinogenic micro-environment in the ovaries of normal hens by altering the PG and oestrogen pathways in a dose-dependent manner.

The objective of the present study was to find the optimum dose of flaxseed that would decrease PG and alter oestrogen pathway endpoints implicated in ovarian cancer. In the study, four groups of fifty 1.5-year-old chickens were fed different amounts of flaxseed (0, 5, 10 or 15% of their total diet) for 4 months and were then killed to collect blood and tissues. Levels of flaxseed lignan metabolites, Enterolactone (EL) and Enterodiol (ED) were measured in the serum, liver and ovaries by liquid chromatography-MS/MS, and n-3 and n-6 fatty acid (FA) levels were measured by GC. The effects of the varied flaxseed doses were assessed by measuring levels of PGE2 and oestrogen metabolites (16-hydroxyestrone (16-OHE1) and 2-hydroxyestrone (2-OHE1)) as well as by analysing the expression of the oestradiol metabolising enzymes CYP3A4 (cytochrome p450, family 3, subfamily A, polypeptide 4), CYP1B1 (cytochrome p450, family 1, subfamily B, polypeptide 1) and CYP1A1 (cytochrome p450, family 1, subfamily A, polypeptide 1) and that of oestrogen receptor α (ERα) in the ovaries. The ratio of n-3:n-FA increased with an increase in flaxseed supplementation and corresponded to a dose-dependent decrease in cyclo-oxygenase-2 protein and PGE2 levels. EL and ED increased in the serum, liver and ovaries with increased concentrations of flaxseed. Flaxseed decreased the expression of ERα in the ovaries. The ratio of 2-OHE1:16-OHE1 in the serum increased significantly in the 15% flaxseed diet, and there was a corresponding increase in CYP1A1 in the liver and decrease in CYP3A4 in the ovaries. CYP1B1 mRNA also decreased with flaxseed diet in the ovaries. The 15% flaxseed-supplemented diet significantly decreased inflammatory PGE2, ERα, CYP3A4, CYP1B1 and 16-OHE1, but it increased CYP1A1 and 2-OHE1, which thus reduced the inflammatory and pro-carcinogenic micro-environment of the ovaries.

Gene polymorphisms in the ornithine decarboxylase-polyamine pathway modify gastric cancer risk by interaction with isoflavone concentrations.

BACKGROUND: The study aimed to examine the association between genes encoding molecules in the ornithine decarboxylase (ODC)-polyamine pathway (ODC1, AMD1, NQO1, NOS2A, and OAZ2) and gastric cancer risk and whether the gene-phytoestrogen interaction modifies gastric cancer risk. METHODS: Among 76 gastric cancer cases and their 1:4 matched controls within the Korean Multi-center Cancer Cohort, a total of 30 SNPs in five genes involved in the ODC pathway were primarily analyzed. The second-stage genotyping in 388 matched case-control sets was conducted to reevaluate the significant SNPs interacting with phytoestrogens during the primary analysis. The summary odds ratios (ORs) [95 % confidence intervals (CIs)] for gastric cancer were estimated. Interaction effects between the SNPs and plasma concentrations of phytoestrogens (genistein, daidzein, equol, and enterolactone) were evaluated. RESULTS: In the pooled analysis, NQO1 rs1800566 showed significant genetic effects on gastric cancer without heterogeneity [OR 0.83 (95 % CI 0.70-0.995)] and a greater decreased risk at high genistein/daidzein levels [OR 0.36 (95 % CI 0.15-0.90) and OR 0.26 (95 % CI 0.10-0.64), respectively; p interaction < 0.05]. Risk alleles of AMD1 rs1279599, AMD1 rs7768897, and OAZ2 rs7403751 had a significant gene-phytoestrogen (genistein and daidzein) interaction effect to modify the development of gastric cancer. They had an increased gastric cancer risk at low isoflavone levels, but a decreased risk at high isoflavone levels (p interaction < 0.01). CONCLUSIONS: Our findings suggest that common variants in the genes involved in the ODC pathway may contribute to the risk of gastric cancer possibly by modulating ODC polyamine biosynthesis or by interaction between isoflavones and NQO1, OAZ2, and AMD1.

Oilseeds ameliorate metabolic parameters in male mice, while contained lignans inhibit 3T3-L1 adipocyte differentiation in vitro.

PURPOSE AND BACKGROUND: The focus was directed to the study of two of the most lignan-rich food sources: sesame and flaxseeds. Recent epidemiological and experimental evidences suggesting that these foods may improve metabolic functions underlying metabolic syndrome (MetS). METHODS: To characterize the effect of these oilseeds on metabolic functions, we conducted an experimental study aimed at preventing adiposity and metabolic imbalance in a mouse model of high-fat diet (HFD)-induced MetS. Statistical analysis was performed by two-way analysis of variance test followed by post hoc Bonferroni analysis. RESULTS: We studied the effect of the oilseeds sesame and flaxseed on metabolic parameters in mice on a HFD. When the HFD was integrated with 20% of sesame or flaxseed flours, the mice showed a decrease in body fat, already at day 15, from time 0. The size of the adipocytes was smaller in epididymal fat, liver steatosis was inhibited, and insulin sensitivity was higher in mice on the supplemented diets. The supplemented diets also resulted in a significant increase in the serum levels of the lignan metabolites enterodiol and enterolactone compared with the controls. The expression of genes associated with the inflammatory response, glucose metabolism, adipose metabolism and nuclear receptor were altered by the oilseed-supplemented diets. Some of the most abundant lignans in these oilseeds were studied in 3T3-L1 preadipocyte cells and were effective in inhibiting adipocyte differentiation at the minimal dose of 1 nM. CONCLUSIONS: The consumption of sesame and flaxseed may be beneficial to decrease metabolic parameters that are generally altered in MetS.

Metabolism of secoisolariciresinol-diglycoside the dietary precursor to the intestinally derived lignan enterolactone in humans.

Secoisolariciresinol-diglycoside (SDG), a natural dietary lignan of flaxseeds now available in dietary supplements, is converted by intestinal bacteria to the mammalian lignans enterodiol and enterolactone. High levels of these lignans in blood and urine are associated with reduced risk of many chronic diseases. Our objective was to determine the bioavailability and pharmacokinetics of SDG in purified flaxseed extracts under dose-ranging and steady-state conditions, and to examine whether differences in secoisolariciresinol-diglycoside purity influence bioavailability. Pharmacokinetic studies were performed on healthy postmenopausal women after oral intake of 25, 50, 75, 86 and 172 mg of secoisolariciresinol-diglycoside. Extracts differing in secoisolariciresinol-diglycoside purity were compared, and steady-state lignan concentrations measured after daily intake for one week. Blood and urine samples were collected at timed intervals and secoisolariciresinol, enterodiol and enterolactone concentrations measured by mass spectrometry. Secoisolariciresinol-diglycoside was efficiently hydrolyzed and converted to secoisolariciresinol. Serum concentrations increased rapidly after oral intake, peaking after 5-7 h and disappearing with a plasma elimination half-life of 4.8 h. Maximum serum concentrations of the biologically active metabolites, enterodiol and enterolactone were attained after 12-24 h and 24-36 h, respectively, and the half-lives were 9.4 h and 13.2 h. Linear dose-responses were observed and secoisolariciresinol bioavailability correlated (r(2) = 0.835) with cumulative lignan excretion. There were no significant differences in the pharmacokinetics of extracts differing in purity, and steady-state serum lignan concentrations were obtained after one-week of daily dosing. In conclusion, this study defines the pharmacokinetics of secoisolariciresinol-diglycoside and shows it is first hydrolyzed and then metabolized in a time-dependent sequence to secoisolariciresinol, enterodiol and ultimately enterolactone, and these metabolites are efficiently absorbed.

An automated dual-gradient liquid chromatography-MS/MS method for the simultaneous determination of ferulic acid, ligustrazine and ligustilide in rat plasma and its application to a pharmacokinetic study.

An automated on-line SPE and innovative fast polarity switch bioanalysis method employing dual-gradient liquid chromatography (DGLC) coupled with mass spectrometry (DGLC-MS/MS) was established and validated for the simultaneous determination of ferulic acid, ligustrazine and ligustilide in rat plasma after administration of Rhizoma Chuanxiong, Angelica sinensis extract or monomer. The proteins in plasma samples were precipitated using acetonitrile: methanol (1:1, v/v). Sulfamethoxazole was used as an internal standard. The DGLC system contains two high-pressure pumps. The first pump was used for on-line solid phase extraction with a Cyclone™ SPE column. Chromatographic separations were performed with the other pump on a Syncronis C18 rapid analytical column. The analytical column was eluted by a gradient program that featured an acetonitrile/methanol/water gradient (flow-rate, 0.4ml/min). DGLC afforded greater convenience for bioanalysis. All analytes were simultaneously monitored in positive- and negative-ion mode by SRM (selective reaction monitoring) using the fast polarity switch speed of TSQ Vantage™. Method validation of the assay was implemented. No significant matrix effect was observed. The LLOQ of all analytes were <1.0ng/ml. The precision, recovery and linearity of the analysis met the pre-established requirements. The method was applied to the pharmacokinetics of ferulic acid, ligustrazine and ligustilide in Rhizoma Chuanxiong or Angelica sinensis extracts or monomers.

Validation of FFQ-based assessment of dietary lignans compared with serum enterolactone in Swedish women.

The validity of using FFQ to assess dietary lignans is uncertain. We aimed to validate the use of FFQ for the assessment of dietary intake of lignans compared to the serum biomarker enterolactone, the main product of dietary lignans' metabolism in human subjects. A random sample of women, aged 55-75 years, from the Swedish Mammography Cohort was selected. Information from two FFQ, the FFQ-87 (sixty-seven food items) and the FFQ-97 (ninety-three food items), and blood samples were collected. Dietary intake of lignans (secoisolariciresinol, matairesinol, lariciresinol, pinoresinol, medioresinol and syringaresinol) was assessed by the FFQ. Serum concentrations of enterolactone were analysed by time-resolved fluoroimmunoassay. The correlation coefficient between energy-adjusted lignan intake and serum enterolactone was estimated in crude and multivariable-adjusted models, taking into account the factors potentially influencing the serum enterolactone. Among the 135 participants aged 55-75 years, with a mean BMI of 26·7 kg/m², the average energy-adjusted intake of total lignans was 1616 (sd 424) and 1516 (sd 409) µg/d according to the FFQ-87 (forty-five food items containing lignans) and the FFQ-97 (sixty-five food items containing lignans), respectively. The mean concentration of serum enterolactone was 23·2 (sd 15·4) nmol/l. The adjusted Pearson's correlation between dietary intake of lignans assessed by the FFQ-97 and serum enterolactone was statistically significant (r 0·22, P= 0·01). No significant correlation was observed for the FFQ-87 (r 0·09, P= 0·30). The present study indicates that the FFQ-97 might be better than the FFQ-87 for assessing dietary intake of lignans, although the correlation was low.

Effects of abomasal infusion of flaxseed (Linum usitatissimum) oil on microbial ß-glucuronidase activity and concentration of the mammalian lignan enterolactone in ruminal fluid, plasma, urine and milk of dairy cows.

Ruminal microbiota plays an important role in the conversion of plant lignans into mammalian lignans. The main mammalian lignan present in the milk of dairy cows fed flax products is enterolactone (EL). The objectives of the present study were to investigate the effects of abomasal infusion of flax oil on the metabolism of flax lignans and concentrations of EL in biological fluids of dairy cows. A total of six rumen-cannulated dairy cows were assigned within a 2 × 3 factorial arrangement of six treatments utilising flax hulls (0 and 15·9 % of DM) and abomasal infusion of flax oil (0, 250 and 500 g/d). There were six periods of 21 d each. Samples were collected during the last 7 d of each period and subjected to chemical analysis. Flax hull supplementation increased concentrations of EL in ruminal fluid, plasma, urine and milk, while flax oil infusion had no effect. Post-feeding, ß-glucuronidase activity in the ruminal fluid of cows infused with 250 g flax oil was significantly lower for cows fed hulls than for those fed the control diet. The present study demonstrated that the presence of a rich source of n-3 fatty acids such as flax oil in the small intestine does not interfere with the absorption of the mammalian lignan EL and that lower ruminal ß-glucuronidase activity had no effect on the conversion of flax lignans into EL in the rumen of dairy cows.

Plasma enterolactone and incidence of endometrial cancer in a case-cohort study of Danish women.

The phyto-oestrogen enterolactone has been hypothesised to protect against hormone-dependent cancers, probably through its antioestrogenic potential. We investigated whether a higher level of plasma enterolactone was associated with a lower incidence of endometrial cancer in a case-cohort study in the 'Diet, Cancer and Health' cohort. The cohort study included 29 875 women aged 50­64 years enrolled between 1993 and 1997. Information on diet and lifestyle was provided by self-administrated questionnaires and blood was drawn from each participant. Time-resolved fluoroimmunoassay was used for biochemical determination of plasma enterolactone. A total of 173 cases and 149 randomly selected cohort members were included. We estimated incidence rate ratio (IRR) and 95% CI by a Cox proportional hazards model. A 20 nmol/l higher plasma concentration of enterolactone was associated with a non-significant lower risk of endometrial cancer (IRR 0.93, 95% CI 0.84, 1.04). When excluding women with low enterolactone concentrations (quartile 1) due to potential recent antibiotic use, the association became slightly stronger, but remained non-significant (IRR 0.90, 95% CI 0.79, 1.02). Menopausal status, hormone replacement therapy or BMI did not modify the association. In conclusion, we found some support for a possible inverse association between plasma enterolactone concentration and endometrial cancer incidence.

Mammary gene expression and activity of antioxidant enzymes and concentration of the mammalian lignan enterolactone in milk and plasma of dairy cows fed flax lignans and infused with flax oil in the abomasum.

The objectives of the study were to investigate the effects of dietary supplementation of flax hulls and/or flax oil on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)) in plasma and the mammary gland and the relative mRNA abundance of antioxidant genes in the mammary gland of dairy cows. A total of eight dairy cows were used in a replicated 4 × 4 Latin square design. There were four treatments: control with no flax hulls (CONT), 9·88% flax hulls in the DM (HULL), control with 500 g flax oil/d infused in the abomasum (COFO), 9·88% flax hulls in the DM and 500 g flax oil/d infused in the abomasum (HUFO). Plasma GPX activity tended to decrease with flax oil supplementation. Cows fed HULL had higher levels of CAT, GPX1 and SOD1 mRNA in the mammary gland and lower mRNA abundance of GPX3, SOD2 and SOD3 compared with those fed CONT. Abundance of CAT, GPX1, GPX3, SOD2 and SOD3 mRNA was down-regulated in the mammary gland of cows fed HUFO compared to those fed CONT. The mRNA abundance of CAT, GPX1, GPX3 and SOD3 was lower in the mammary gland of cows fed COFO than in the mammary gland of cows fed CONT. The present study demonstrates that flax hulls contribute to increasing the abundance of some antioxidant genes, which can contribute to protecting against oxidative stress damage occurring in the mammary gland and other tissues of dairy cows.

A single dose of enterolactone activates estrogen signaling and regulates expression of circadian clock genes in mice.

Enterolactone (EL) is an enterolignan produced by gut microbiota from dietary plant lignans. Epidemiological and experimental studies suggest that EL and plant lignans may reduce the risk of breast and prostate cancer as well as cardiovascular disease. These effects are thought to at least in part involve modulation of estrogen receptor activity. Surprisingly little is known about the in vivo estrogenicity of EL. In the present study, we investigated the target tissues of EL, the genes affected by EL treatment, and the response kinetics. Following a single dose of EL, luciferase was significantly induced in reproductive and nonreproductive tissues of male and female 3xERE-luciferase mice, indicating estrogen-like activity. Microarray analysis revealed that EL regulated the expression of only 1% of 17ß-estradiol target genes in the uterus. The majority of these genes were traditional estrogen target genes, but also members of the circadian signaling pathway were affected. Kinetic analyses showed that EL undergoes rapid phase II metabolism and is efficiently excreted. In vivo imaging demonstrated that the estrogen response followed similar, fast kinetics. We conclude that EL activates estrogen signaling in both male and female mice and that the transient responses may be due to the fast metabolism of the compound. Lastly, EL may represent a link among diet, gut microbiota, and circadian signaling.