Determination of zearalenone in raw milk from different provinces of Ecuador

Background and Aim: Zearalenone (ZEA) is a mycotoxin from the fungus Fusarium. ZEA can adopt a similar configuration to 17β-estradiol and other natural estrogens. Problems in the reproductive function of humans and animals have been reported for ZEA and its metabolites. This study aimed to determine ZEA in raw milk produced in representative milk production areas in Ecuador. Materials and Methods: A total of 209 samples were obtained in April and November 2019 (rainy season) and June and August 2019 (dry season). A competitive enzyme-linked immunosorbent assay technique was used to detect ZEA concentrations. Results: ZEA was determined in 99.5% (208 of 209) of the samples; however, all samples were below the maximum limits allowed (0.03-1 mg/L) in food for direct human consumption according to the Food and Agriculture Organization and European legislations. The mean (range) concentration was 0.0015 (0-0.0102) mg/L. The results did not vary significantly (p≥0.05) by cantons, provinces, weather, climate regions, types of producers, and production systems according to Wilcoxon and Kruskal–Wallis non-parametric tests. There were significant differences only between the months under study (p≤0.05). Conclusion: ZEA in raw milk from Ecuador does not represent a threat to public health. However, it is recommended to continue analyzing ZEA due to its presence in milk. It could also be present with other mycotoxins that cause harmful synergistic and additive effects to consumers.

Estrogens and antiestrogens. Modern synthetic approaches to directed modification of estra-1,3,5(10)-triene steroids: goals, reactions, and methods

The monograph summarizes the information over the past 20 years on the currently widely used and promising methods for the synthesis of estra-1,3,5(10)-triene derivatives by modifying natural estrogens - estrone and estradiol. The main practical goals of modifying this class of steroids and achievements in the chemistry of steroidal antiestrogens, which are promising drugs for hormonal therapy, are considered. Special attention is paid to the stereochemical features of the reactions and the specific problems of modification of the steroid nucleus of estratrienes associated with the presence of an aromatic fragment in their structure. In addition, the data on the reactivity and stereochemical aspects of the transformations of 13-epiestratriene steroids were summarized. The monograph is intended for a wide range of specialists in the field of organic synthesis, organic, bioorganic, and medicinal chemistry.

Ultra-low dose estradiol plus dydrogesterone: a role in prevention of the development and progression of atherosclerosis

Active development of the "anti-aging medicine", attempts to slow down biological (including vascular) aging led to the creation of new pharmaceuticals including menopausal hormone therapy. The vascular wall protective mechanism of the hormones is not completely clear, but it was shown that natural estrogens are able to control the condition of the vascular wall, prevent platelet adhesion, control a range of metabolic and trophic and energy processes in the endothelium of the vascular wall, producing antithrombogenic factors, namely their inhibition contributes to the development of atherosclerosis. It is known that standard and low-dose estrogen may restore the impaired antithrombogenic potential of the vascular wall, provided its initial reduction does not exceed 20%. The issue of the role and possibilities of correction of the antithrombogenic activity of the vascular wall with ultra-low dose estradiol remained unresolved. As a "clinical model" for the study of this issue, we formed 2 groups of patients: in the study group patients received ultra-low dose estradiol plus dydrogesterone, subjects from the control group received beta-alanine. Three-year follow-up showed a decrease in antithrombogenic activity of the vascular wall in control subjects after 2 and 3 years of follow-up according to the M.V. Baluda's test versus subjects treated with ultra-low dose estrogen plus dydrogesterone. The decrease of the relative risk of reduction of the antithrombogenic activity of the vascular wall with the use of ultra-low dose estrogen plus dydrogesterone during the first two years was 2.3 times, and during the 3 years of follow-up 3.8 times versus control. Thus, prescribing only ultra-low dose estradiol plus dydrogesterone for patients with normal antithrombogenic activity of the vessel wall at baseline reliably lowers the risk of long-term reduction of antithrombogenic potential of the vascular wall.

Occurrence, Impact on Agriculture, Human Health, and Management Strategies of Zearalenone in Food and Feed: A Review

Mycotoxins represent an assorted range of secondary fungal metabolites that extensively occur in numerous food and feed ingredients at any stage during pre- and post-harvest conditions. Zearalenone (ZEN), a mycotoxin categorized as a xenoestrogen poses structural similarity with natural estrogens that enables its binding to the estrogen receptors leading to hormonal misbalance and numerous reproductive diseases. ZEN is mainly found in crops belonging to temperate regions, primarily in maize and other cereal crops that form an important part of various food and feed. Because of the significant adverse effects of ZEN on both human and animal, there is an alarming need for effective detection, mitigation, and management strategies to assure food and feed safety and security. The present review tends to provide an updated overview of the different sources, occurrence and biosynthetic mechanisms of ZEN in various food and feed. It also provides insight to its harmful effects on human health and agriculture along with its effective detection, management, and control strategies.

Development and validation of a high performance liquid chromatography/diode array detection method for estrogen determination: Application to residual analysis in meat products

In this work, an HPLC-DAD method was developed for the residual analysis of some estrogens such as estrone (E1), 17-β estradiol (E2), estriol (E3), natural estrogens, and 17-α ethinylestradiol (E4), an exoestrogen, in meat samples of different categories (chicken, n = 155, beef, n = 124, sheep, n = 122, and camels, n = 40), collected from the Saudi Market. Although banned, the use of E4 as a growth promoter in the black market is still encountered. Symmetry C18 column (3.5 µm, 4.6 mm × 150 mm) was used with a mobile phase consisting of 50% aqueous acetonitrile. Protein precipitation with acetonitrile was used for the sample preparation. The method was fully validated, as per the ICH guidelines, in the concentration ranges of 0.35–125 µg/g (E1, E2), 0.188–125 µg/g (E3), and 0.188–450 µg/g (E4). The method allowed the trace analysis of estrogens with LOD values of 0.094 (E3, E4) and 0.126 µg/g (E1, E2), and LOQ values of 0.188 (E3, E4) and 0.350 µg/g (E1, E2). The analyzed samples contained different levels of estrogens. Within the same category, processed products contained the highest levels of E4, while the internal organs contained the least estrogen content. Finally, the estimated daily intake, µg/kg bw/day, of estrogens through the consumption of meat-based food products was calculated.

Natural estrogens in surface waters of a catchment with intensive livestock farming in Switzerland

Agriculture is a source of natural estrogens such as 17β-estradiol in streams, but in our study concentrations never exceeded European environmental quality standards for more than a day.