Biosynthesis and Identification of Clenbuterol Metabolites in Urine and In Vitro Microsome Incubation Samples Using UHPLC-Q-Exactive Orbitrap Mass Spectrometry: A Comparison Between Human and Bovine Metabolism.

Clenbuterol (Clb) is a β2-agonist drug included in the list of substances prohibited during and out of competition by the World Anti-Doping Agency (WADA-AMA). Several adverse analytical findings have been detected by accredited WADA laboratories, but athletes often claim that results are due to dietary contamination. In this contribution, bovine microsomal incubation and the excretion of bovine and human urinary metabolites of Clb were analyzed and compared using liquid chromatography electrospray Q-Exactive-Orbitrap mass spectrometry to determine differences in Clb metabolism.

Effects of Dimenhydrinate on Motor Behavior and Vascular Function: Possible Implications for the Field of Sports.

Several studies have described the sedative effects of dimenhydrinate (DMH), although others report a stimulant effect on psychomotor functions. Because the first generation of antihistamines was shown to seriously impair cognitive psychomotor and driving performance in healthy volunteers, the aim of our research was to determine the effect of DMH by testing physical activity and cognitive and cardiovascular functions using an animal model to identify a possible stimulatory effect. The study protocol consisted of two phases.

Reviewing Glycosyl-Inositols: Natural Occurrence, Biological Roles, and Synthetic Techniques.

Glycosyl-inositols are molecules consisting of one or more α- or β-D-glycosyl residues bonded primarily to inositol or methyl-inositol. These derivatives are found in plants, yeast, bacteria, and parasites, and exhibit diverse biological properties. The limited availability of glycosyl inositols from natural sources has led to significant interest in chemical and enzymatic synthesis techniques due to their potential applications in various fields.

Determination of the Botanical Origin and Physicochemical Properties of a Propolis Sample Through an Integrated Methodology.

The growing interest in products of natural origin has led to the implementation of products such as propolis because they possess biological properties that are useful in the treatment of various ailments, so it is relevant to know the botanical origin of the physicochemical compounds that provide propolis with its biological properties. To identify the floral sources that provide resources to bees for the manufacture of propolis, several methodologies have been implemented, such as palynological analysis, which, through pollen content, has made it possible to identify the plant species that provide resources to bees. On the other hand, analysis of the physicochemical components of propolis has revealed that phenols and flavonoids are mainly responsible for the biological activity of propolis.

Quantification and enantiomeric distribution of clenbuterol in several bovine tissues using UHPLC-tandem mass spectrometry: Evaluation of a risk factor associated with meat contamination.

Clenbuterol (Clb) (4-amino-α-[(tert-butylamine) methyl]-3,5-dichlorobenzyl alcohol) is a sympathomimetic agent that exhibits β2-agonist activity. It is applied as a bronchodilatory, tocolytic, and mucolytic agent and is authorized for clinical management in both human and veterinary therapeutics as a racemic mixture. However, its use is strictly prohibited in animals destined for food production in countries in the European Union and in the United States and Mexico, among many others.

Recent Developments and Applications of Nanosystems in the Preservation of Meat and Meat Products.

Due to their high water, lipid, and protein content, meat and meat products are highly perishable. The principal spoilage mechanisms involved are protein and lipid oxidation and deterioration caused by microbial growth. Therefore, efforts are ongoing to ensure food safety and increase shelf life.

Determination of clenbuterol at trace levels in raw gelatin powder and jellies using ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry.

Clenbuterol is present in animal tissues and organs and, therefore, potentially present in gelatin derived from animal sources. The objective of this study was to develop a method for identify an quantify traces of clenbuterol in gelatin and jellies. The clenbuterol calibration curve showed linearity in the range of 20-1000 pg mL.

Influence of Stabilizing and Encapsulating Polymers on Antioxidant Capacity, Stability, and Kinetic Release of Thyme Essential Oil Nanocapsules.

The release kinetics, stability, and antioxidant capacity of thyme essential oil polymeric nanocapsules as a function of encapsulating (poly-ε-caprolactone and ethylcellulose) and stabilizing (polyvinyl alcohol and Pluronic F-127) polymers were established. Samples were evaluated in terms of particle size, zeta potential, release kinetics, calorimetry, infrared spectra, antioxidant capacity, and diffuse reflectance. The particle size obtained was below 500 nm in all cases, ensuring nanometric size.

Quantification and Stereochemical Composition of R-(-) and S-(+)-Clenbuterol Enantiomers in Bovine Urine by Liquid Chromatography-Tandem Mass Spectrometry.

Clenbuterol (4-amino-α-[(tert-butylamino)methyl]-3,5-dichlorobenzylalcohol) is a β2-adrenergic agonist. The consumption of meat contaminated with clenbuterol can lead to increased heart rate, blood pressure, anxiety, palpitations and skeletal muscle tremors. Several analytical methods have been developed to identify and quantify clenbuterol in different biological matrices.

Development of in-house materials for the verification of specific gravity measurements: Homogeneity, stability, and proficiency studies.

We developed and evaluated the properties of in-house urine reference materials for the verification of laboratory refractometers, which are frequently used in clinical chemistry and doping testing laboratories. Urine was gathered from 26 healthy volunteers (16 male 30 ± 5 years old and 10 female 29 ± 4 years old), from which two urine batches were obtained: one with a low specific gravity (1.012± 0.

Evaluation of R- (-) and S- (+) Clenbuterol enantiomers during a doping cycle or continuous ingestion of contaminated meat using chiral liquid chromatography by LC-TQ-MS.

Clenbuterol is known to improve competition resistance and muscular growth in athletes. Although it is an illegal drug, its use by farmers is widely spread to induce growth of their cattle. Thus, when clenbuterol is found in the urine of an athlete, there is doubt whether it was consumed with doping purposes or if it is due to the consumption of meat from a clenbuterol-fed animal.

A Novel Phospholipase A2 Isolated from Possesses Neurotoxic Activity.

Zoanthids of the genus are distributed worldwide in shallow waters around coral reefs. Like all cnidarians, they possess nematocysts that contain a large diversity of toxins that paralyze their prey. This work was aimed at isolating and functionally characterizing a cnidarian neurotoxic phospholipase named A2-PLTX-Pcb1a for the first time.

Banned substances and their incidence: A retrospective view of the national laboratory of prevention and doping control of Mexico.

The use of banned substances to increase athletes' performance has been a scourge in international sport. In this sense, the World Anti-Doping Agency (WADA-AMA) has implemented a series of standards that harmonize the fight against doping. In particular, accredited WADA-AMA laboratories play an important role in the eradication of sports doping.

Resolution of R-(-) and S-(+)- enantiomers of clenbuterol in pharmaceutical preparations and black-market products using liquid chromatography-tandem mass spectrometry.

Several banned substances are illegally used by athletes in racemic mixtures for performance enhancement. These include clenbuterol, methyl hexaneamine, methamphetamines, and amphetamines. Clenbuterol is present in a large number of doping samples from Olympic and non-Olympic athletes that have adverse analytical findings (AAFs).

Effect of bis-1,4-dihydropyridine in the kidney of diabetic rats.

The in vivo effectiveness of 4-dihydropyridine (bis-1,4-DHP), a new calcium-channel blocker, as a nephroprotector in isolated perfused kidney was evaluated by determining its effects on parameters associated with renal injury in diabetic rats. Diabetes in male Wistar rats, control, diabetic, control + bis-1,4-DHP, and diabetic + bis-1,4-DHP, was induced by a single administration of STZ (55 mg·kg(-1), i.p.

Comparative study using different infrared zones of the solventless activation of organic reactions.

In this work, the results of a study comparing the use of irradiation from different regions of the infrared spectrum for the promotion of several organic reactions, are presented and discussed. This use of eco-conditions provides a green approach to chemical synthesis. A set of ten different organic reactions were evaluated, including the Knoevenagel, Hantzsch, Biginelli and Meldrum reactions.

Antimalarial activity of ultra-short peptides.

Ultra-short peptides 1-9 were designed and synthesized with phenylalanine, ornithine and proline amino acid residues and their effect on antimalarial activity was analyzed. On the basis of the IC(50) data for these compounds, the effects of nature, polarity, and amino acid sequence on Plasmodium berghei schizont cultures were analyzed too. Tetrapeptides Phe-Orn-Phe-Orn (4) and Lys-Phe-Phe-Orn (5) showed a very important activity with IC(50) values of 3.