Quantitative analysis of urinary daidzein and equol by gas chromatography after solid-phase extraction and high-performance liquid chromatography

Microwave Microfluidic Sensor for Detection of High Equol Concentrations in Aqueous Solution

This paper presents a Peano fractal geometry complementary split ring resonator (PFCSRR) loaded microstrip transmission line with a microfluidic channel for equol (EQ) sensing in a high and wide range of concentrations in aqueous solution. The proposed sensor was designed based on a CSRR loaded microstrip line with a Peano fractal in the center of a CSRR and validated through simulation and experiment. The microfluidic channel was fabricated using polydimethylsiloxane (PDMS) and installed to cover the sensing area. The free space, empty microfluidic channels, deionized (DI) water, dimethyl sulfoxide (DMSO), and various concentrations of EQ were measured by a microwave sensor through sample-filled microfluidic channels. Detection of high levels of EQ was in the concentration range of 0.01 mM - 100 mM. The materials under test (MUTs) were measured in the frequency range of 1.0 GHz-3.5 GHz based on the magnitude of the transmission coefficient (S₂₁) and resonance frequency (F_r) at room temperature. The S₂₁ and F_r were recorded and analyzed by logarithmic concentrations of EQ for the determinant of the correlations between EQ concentration and S₂₁ and F_r. Principal component analysis (PCA) and K-means clustering were used to analyze and classify groups of MUTs.

Isoflavone supplementation reduces DNA oxidative damage and increases O-β-N-acetyl-D-glucosaminidase activity in healthy women

Phenolic compounds are believed to boost the human antioxidant defense system and health; therefore, the aim of this research was to investigate the hypothesis that soy isoflavones (IFs) provide antioxidant protection in healthy women by evaluating DNA resistance to oxidative damage and O-β-N-acetyl-D-glucosaminidase (OGA) activity. An IF supplement (80 mg/d) was given to 9 postmenopausal women and 13 young women for 6 months and then stopped up to the 14th month. The women were allowed to consume their normal diet. Blood samples were collected at the beginning of the study after 2, 4, and 6 months and then at the 8th and 14th months. Plasma concentrations of genistein and daidzein, total antioxidant capacity, plasma vitamin status, markers of oxidative stress (red blood cell membrane fluidity, activity of the red blood cell cytosolic enzyme OGA and lymphocyte DNA susceptibility to oxidative stress), and serum lipid profile were analyzed. Analysis of variance for repeated measures was used for statistical analysis. Plasma concentrations of IFs rose significantly during the supplementation period, and plasma total antioxidant capacity increased in young women; membrane fluidity and OGA activity increased, and DNA oxidative damage decreased (P < .05) at 4 months, then returned to the basal level. There was a significant inverse correlation between DNA damage and plasma IF concentrations (P < .01). The results indicated a positive effect of IF supplementation on oxidative stress in women, thus suggesting that the healthful action ascribed to soy consumption may be partially related to the antioxidant potential of IFs.

Equol status modifies the association of soy intake and mammographic density in a sample of postmenopausal women

Only 30% to 50% of people produce the daidzein-metabolite equol after eating soy. We conducted a cross-sectional study of the associations between equol status, intake of soy foods, and mammographic density in a sample of postmenopausal women recruited at a radiology clinic near Buffalo, New York. Participants were 48 to 82 years old, had no history of cancer or breast reduction/augmentation, and no recent use of antibiotics or hormones. Percent density was measured by computer-assisted analysis of digitized images of craniocaudal films. Equol status was assessed using a soy-challenge protocol and usual soy intake by questionnaire. General linear models were used to assess independent and joint effects of equol status and intake of soy on multivariate adjusted percent density (covariates included age, body mass index, parity, age at first birth, and ever use of combined hormone therapy). Of 325 enrolled, 232 (71%) participants completed study assessments and are included in the present analysis. Mean percent density was 34% (+/-18%). Seventy-five (30%) participants were producers of equol. Forty-three (19%) participants reported regularly eating >1 soy food or supplement/wk. There were no significant independent associations of equol status or soy intake with percent density, but the interaction between these factors was significant (P < 0.01). Among equol producers, those with weekly soy intake had lower percent density (30.7% in weekly consumers of soy versus 38.9% in others; P = 0.08); among nonproducers, weekly soy intake was associated with higher percent density (37.5% in weekly soy consumers versus 30.7% in others; P = 0.03). Results suggest that equol producers and nonproducers may experience different effects of dietary soy on breast tissue.