Unveiling the Remarkable Antioxidant Activity of Plant-Based Fish and Seafood Analogs through Electrochemical Sensor Analysis.

The global consumption of vegan foods is experiencing an expressive upward trend, underscoring the critical need for quality control measures based on nutritional and functional considerations. This study aimed to evaluate the functional quality of caviar and salmon analog food inks based on pulses combined with nano ingredients and produced in our laboratory (LNANO). The primary objective of this work was to determine the total antioxidant compounds contained in these samples using a voltammetric technique with a glassy carbon electrode. The samples underwent ethanolic extraction (70%) with 1 h of stirring. The voltammograms were acquired in a phosphate buffer electrolyte, pH 3.0 with Ag/AgCl (KCl 3 mol L-1) as the reference electrode and platinum wire as the auxiliary electrode. The voltammograms revealed prominent anodic current peaks at 0.76-0.78 V, which are attributed to isoflavones. Isoflavones, known secondary metabolites with substantial antioxidant potential commonly found in pulses, were identified. The total isoflavone concentrations obtained ranged from 31.5 to 64.3 mg Eq genistein 100 g-1. The results not only validated the efficacy of the electrochemical sensor for quantifying total antioxidant compounds in the samples but also demonstrated that the concentration of total isoflavones in caviar and salmon analogs fell within the expected limits.

The natural plant stress elicitor cis-jasmone causes cultivar-dependent reduction in growth of the stink bug, Euschistus heros and associated changes in flavonoid concentrations in soybean, Glycine max.

To test the hypothesis that the plant stress related elicitor cis-jasmone (cJ) provides protection in soybean pods against the seed-sucking stink bug pest, Euschistus heros, the growth of E. heros on cJ-treated pods was investigated using three soybean cultivars differing in insect susceptibility, i.e. BRS 134 (susceptible), IAC 100 (resistant) and Dowling (resistant). E. heros showed reduced weight gain when fed cJ-treated Dowling, whereas no effect on weight gain was observed when fed other treated cultivars. Using analysis of variance, a three factor (cultivar x treatment x time) interaction was observed with concentrations of the flavonoid glycosides daidzin and genistin, and their corresponding aglycones, daidzein and genistein. There were increases in genistein and genistin concentrations in cJ-treated Dowling at 144 and 120 h post treatment, respectively. Higher concentrations of malonyldaidzin and malonylgenistin in Dowling, compared to BRS 134 and IAC 100, were observed independently of time, the highest concentrations being observed in cJ-treated seeds. Levels of glycitin and malonylglycitin were higher in BRS 134 and IAC 100 compared to Dowling. Canonical variate analysis indicated daidzein (in the first two canonical variates) and genistein (in the first only) as important discriminatory variables. These results suggest that cJ treatment leads to an increase in the levels of potentially defensive isoflavonoids in immature soybean seeds, but the negative effect upon E. heros performance is cultivar-dependent.

Development and validation of a simple and rapid liquid chromatography method for the determination of genistein in skin permeation studies.

Genistein (GEN) has potential advantages for topical skin delivery, but no literature data are available for its quantitation in different skin layers, such as the stratum corneum (SC). Therefore, a simple, rapid, selective and sensitive bioanalytical method was developed and validated for GEN quantitation in porcine skin samples following in vitro permeation studies. GEN was assayed by HPLC with UV-Vis detection (270 nm) using 0.5% acetic acid in water-n-propanol-acetonitrile (50 : 2 : 48, v/v/v) as mobile phase (flow-rate of 1.0 mL/min). Specificity was demonstrated since endogenous skin components did not interfere with GEN peak. Standard analytical curve was linear over the concentration range (0.1-60 µg/mL) and the lower limit of quantitation was determined for different skin layers (100 ng/mL). GEN recovery from skin layers ranged from 95.57 to 97.57%. Permeation studies were carried out using an automated vertical diffusion cell apparatus. No fluctuation on the amount of GEN retained in the SC was observed over time, but increasing amounts of the drug were found in deeper layers of the skin. The method was reliable and reproducible for the quantitation GEN in skin samples enabling the determination of the cutaneous penetration profile of this drug in permeation experiments.

Antioxidant characterization of soy derived products in vitro and the effect of a soy diet on peripheral markers of oxidative stress in a heart disease model.

This study analyzed and compared the content of isoflavones in 2 soy products, the effectiveness of isoflavones as antioxidants, in vitro, and demonstrated the antioxidant effect of a soy diet in rats with myocardial infarction (MI). Isoflavone content was analyzed in soybean hypocotyl (SH) and isolated soy protein (ISP). The quality (TAR) and quantity (TRAP) of antioxidants present in the samples was quantified. The amount of daidzin was higher in SH (9 times) and genistein in ISP (5 times). SH presented a 3-fold increase in TAR, while both products exhibited same TRAP. The rats were fed an ISP diet for 9 weeks. Animals were distributed among 6 treatment groups: (i) Sham Casein; (ii) Infarct Casein < 25%; (iii) Infarct Casein > 25%; (iv) Sham Soy; (v) Infarct Soy < 25%; and (vi) Infarct Soy > 25%. MI was induced 5 weeks after the commencement of the diets. Lipid peroxidation (LPO), antioxidant enzyme activity, and levels of nitrites/nitrates were determined in blood. Rats receiving the ISP diet demonstrated increased activity of antioxidant enzyme activity and nitrite/nitrate content. In addition, the increase in LPO seen in rats subjected to MI was significantly mitigated when the ISP diet was given. These findings suggest a nutritional approach of using a soy-based diet for the prevention of oxidative-stress-related diseases such as heart failure.

Voltammetric determination of the phytoestrogen genistein in soy flours and soy based supplements using cationic surfactant cetyltrimetylammonium bromide.

This paper proposes a methodology based on electrochemical reduction for a fast, specific and sensitive determination of genistein by square-wave voltammetry (SWV). The highest peak currents and optimal definition of reduction peak of genistein was obtained by using a supporting electrolyte consisted of 0.04 mol L(-1) phosphate buffer-methanol (8:2, v/v) solution at pH 7.5 and cationic surfactant 2.21 x 10(-4) mol L(-1) cetyltrimethylammonium bromide (CTAB). The peak current was proportional to the concentration of genistein in the range 1.14 x 10(-7) to 1.09 x 10(-6) mol L(-1), with a detection limit and quantification of 3.43 x 10(-8) mol L(-1) and 1.14 x 10(-7) mol L(-1), respectively. The extraction procedure was evaluated for a better determination of genistein contained in soy flour and soy based supplements. The efficiency of the proposed methodology was demonstrated by comparing the results obtained by SWV with those obtained by the high-performance liquid chromatography (HPLC) method.

Enhanced in vitro and in vivo antioxidant activity and mobilization of free phenolic compounds of soybean flour fermented with different beta-glucosidase-producing fungi.

AIMS: To evaluate the soybean polyphenol glucosides bioconversion to aglycone forms by different beta-glucosidases-producing filamentous fungi to enhance their antioxidant activity. METHODS AND RESULTS: Soybean defatted flour was submitted to solid-state fermentation with Aspergillus niger, Aspergillus niveus and Aspergillus awamori. The fungi studied produced approximately the same beta-glucosidase activity units amount when p-nitrophenyl-beta-d-glucopyranoside was used as substrate for the assay. However, electrophoretic analysis, using 4-methylumbellipheryl-beta-d-glucopyranoside as substrate, showed that beta-glucosidase produced by A. niveus was more active. Fermented methanolic extracts showed an increase in polyphenol and genistein contents and antioxidant activities. The highest genistein content was found in soybean fermented by A. niveus. Methanolic extracts of the soybean fermented by the different fungi showed a similar capacity of scavenging H(2)O(2) generated in vivo by the tumour promoter 12-O-tetradecanoyl phorbol-13-acetate. CONCLUSIONS: A. niveus synthesized a beta-glucosidase with higher specificity to hydrolyse genistin beta-glycosidic bond than those produced by A. awamori and A. niger. SIGNIFICANCE AND IMPACT OF THE STUDY: The utilization of these beta-glucosidases-producing fungi in soybean fermentation processes resulted in the obtaining of methanolic extracts with different antioxidant potentials that could be used either therapeutically or as an antioxidant in nonphysiological oxidative stress conditions, as the one induced in skin by UV radiation.

Changes in isoflavone profiles of soybean treated with gamma irradiation.

Soybean is an important Brazilian agricultural commodity that contains a high concentration of isoflavones. Many studies showed that isoflavones are active in the prevention of many human diseases. However, the correct processing techniques used to prepare the soy foodstuffs are important to maintain the active forms. The objective of this study was to evaluate the effect of gamma irradiation on the isoflavone contents of the defatted soybean flour when compared with soybean molasses, a derivative from the soybean food production. After extracting phenolic compounds with methanol aqueous solution (80%), isoflavones were detected by reverse-phase high-performance liquid chromatography/diode-array detector. The radiation doses of 2 and 5 kGy presented a small effect on the isoflavones content of defatted soy flour. Samples irradiated at 50 kGy showed lower isoflavone contents. The observed reduction in the concentration of isoflavones-daidzein, glycitein and genistein-induced by gamma radiation in soy molasses was not significant in defatted soy flour, thus suggesting that isoflavones in defatted soy flour were not eliminated by gamma radiation at rates up to 50 kGy.

Analysis of isoflavonoids from leguminous plant extracts by RPHPLC/DAD and electrospray ionization mass spectrometry.

Traditionally, food is associated with energetic and nutritious characteristics such as sources of carbohydrates, proteins and lipids. Recently, however, foods with bioactive substances such as isoflavones have received great attention. The objective of this study was therefore to evaluate the presence of the isoflavones daidzein, glycitein, genistein and their conjugated forms in grains and leaves of several leguminous plants utilized largely in Brazilian cuisine. Grains used in Peruvian cuisine were also analyzed. After extracting phenolic compounds with methanol (80%), isoflavones as detected by reversed-phase high-performance liquid chromatography/ diode-array detector were only found in chickpeas and soybean. Chickpea extracts showed only the isoflavone genistein at 31 microg/g defatted flour. Detection of these isoflavones was confirmed by electrospray ionization mass and tandem mass spectrometric experiments. For soybean, a distinct distribution of isoflavones was found in hypocotyls and cotyledon. The highest concentration of isoflavones found was approximately 5.9 mg/g for hypocotyls, whereas the total concentration of isoflavone was around 0.4 mg/g for the cotyledons (dry matter). These results indicate that isoflavone concentrations vary within the different tissues of the leguminous species tested.

Development and validation of a LC method for determination of genistein in topical nanoemulsions.

The aim of this study was to develop and validate an isocratic LC method for the quantification of genistein in topical nanoemulsions. The analyses were performed at room temperature on a reversed-phase C18 column using a mobile phase composed of methanol/water/acetonitrile (70:25:5, w/w/w) at 1.0 ml x min(-1). The detection was carried out on a UV detector at 327 nm. The linearity, in the range of 25-75 microg/ml, presented a determination coefficient (r2) higher than 0.999, calculated by the least square method. No interferences from the excipients (egg-lecithin, octyldodecanol or medium chain triglycerides) were detected. The R.S.D. values for intra- and inter-day precision experiments were lower than 2.3%. The recovery of genistein from nanoemulsions ranged from 96.6% to 106.6%. The excellent performance of the method, its linearity, accuracy and precision, demonstrate that it can be readily used to quantify genistein incorporated in nanoemulsions.

Avaliação das concentrações plasmática e urinária de isoflavonas purificadas de soja / Evaluation of plasmatic and urinary concentrations of purified soy isoflavones

Com atividade antioxidante e estrogênica, isoflavonas de soja têm sido associadas à diminuição do risco de câncer e doenças cardiovasculares. Assim, buscou-se nesse trabalho a padronização de um método de extração de isoflavonas a partir do melaço de soja e avaliar a respectiva concentração plasmática e urinária após o consumo deste extrato, em coelhos. As isoflavonas foram extraídas em etanol 90 por cento e purificadas em uma coluna de extração em fase sólida C18, obtendo-se rendimento de 81 por cento. O extrato purificado foi adicionado à dieta dos animais (5 mg de isoflavonas/kg de peso corporal/dia), que foram observados por período experimental de 6 meses...