Dual liquid-liquid extraction followed by LC-MS/MS method for the simultaneous quantification of melatonin, cortisol, triiodothyronine, thyroxine and testosterone levels in serum: Applications to a photoperiod study in rats

Cyanoacetohydrazide as a Novel Derivatization Agent for the Determination of UHPLC-HRMS Steroids in Urine

The possibility of cyanoacetohydrazide usage as a novel derivatizing agent is demonstrated in the presented article, and a comparison with hydroxylamine as the most commonly used reagent is provided. Optimal conditions for steroid derivatization with cyanoacetohydrazide are provided. According to the collected data, the maximum yield of derivatives was observed at pH 2.8 within 70 min at 40 °C with 5 ng/mL limit of detection for all investigated analytes. It was shown that cyanoacetohydrazide derivatives produces both syn- and anti-forms as well as hydroxylamine, and their ratios were evaluated and shown in presented work. An efficiency enchantment from two to up to five times was achieved with a novel derivatization reagent. Its applicability for qualitative analysis of steroids in urine was presented at real samples. Additionally, the reproducible fragmentation of the derivatizing agent in collision-induced dissociation offers opportunities for simplified non-targeted steroidomic screening. Furthermore, cyanoacetohydrazide increases ionization efficiency in positive mode, which can eliminate the need for redundant high-resolution instrument runs required for both positive and negative mode analyses.

Cherries with Different Geographical Origins Regulate Neuroprotection in a Photoperiod-Dependent Manner in F344 Rats

The photoperiod is the main environmental cue that drives seasonal adaptive responses in reproduction, behavior, and metabolism in seasonal animals. Increasing evidence suggests that (poly)phenols contained in fruits can also modulate seasonal rhythms. (Poly)phenol-rich diets are associated with an improvement in cognitive function and neuroprotection due to their anti-inflammatory and antioxidative properties. However, it is unknown whether cherries affect neuroprotection in a photoperiod-dependent manner. To test this, F344 rats were exposed to L6 (6 h light/day), L12 (12 h light/day) and L18 (18 h light/day) photoperiods and fed a standard chow diet supplemented with either a control, lyophilized cherry 1 or cherry 2 with distinctive phenolic hallmarks. Physiological parameters (body weight, eating pattern index (EPI), testosterone, T4/T3) and hypothalamic key genes (Dio2, Dio3, Raldh1 and Ghrh) were strongly regulated by the photoperiod and/or fruit consumption. Importantly, we show for the first time that neurotrophs (Bdnf, Sod1 and Gpx1) in the hippocampus are also regulated by the photoperiod. Furthermore, the consumption of cherry 2, which was richer in total flavonols, but not cherry 1, which was richer in total anthocyanins and flavanols, enhanced neuroprotection in the hippocampus. Our results show that the seasonal consumption of cherry with a specific phenolic composition plays an important role in the hippocampal activation of neuroprotection in a photoperiod-dependent manner.

Rapid and Simultaneous Determination of Anabolic Andro-Genic Steroids in Livestock and Poultry Meat Using One-Step Solid-Phase Extraction Coupled with UHPLC-MS/MS

Anabolic androgenic steroids (AASs) are usually illegally added to animal feed because they can significantly promote animal growth and increase carcasses' leanness, which threatens the safety of animal-derived foods and indirectly hazards human health. This study aimed to establish an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous detection of twelve AAS residues in livestock and poultry meat. The homogenized samples were extracted with acetonitrile containing 1% acetic acid (v/v) and purified using the one-step extraction column. After concentration using nitrogen, the residues were redissolved in acetonitrile and then quantified with an external standard method using UHPLC-MS/MS. The results showed that the above-mentioned method had a satisfactory linear correlation (R2 ≥ 0.9903) with a concentration range of 1-100 μg/L, and the limits of detection (LODs) and quantification (LOQs) were 0.03-0.33 μg/kg and 0.09-0.90 μg/kg, respectively. With the intraday and interday precision less than 15%, the average recoveries of pork, beef, lamb, and chicken, at different spiked levels, ranged from 68.3 to 93.3%, 68.0 to 99.4%, 71.6 to 109.8%, and 70.5 to 97.7%, respectively. Overall, the established method is validated, precise, and capable of the high-throughput determination of the residues of twelve AASs in livestock and poultry meat.

UPLC-MS/MS simultaneous quantification of urinary circadian rhythm hormones and related metabolites: Application to air traffic controllers

Civil aviation flight crew and civil aviation air traffic controllers are prone to circadian rhythm abnormalities, which can lead to a slew of other maladies. It could endanger people's health and provide a serious threat to the safety of civil aviation flights if it is not appropriately evaluated and addressed. Early detection of rhythm irregularities and prompt treatment for particular populations that are vulnerable to rhythm disorders are crucial for enhancing civil aviation safety. In general, monitoring of the classical circadian rhythm biomarkers (melatonin or cortisol) in plasma or saliva is an effective way to evaluate the rhythm status. Due to the challenging sample procedure and the trauma of plasma, urine sample testing has received an increasing amount of attention. While, urine circadian rhythm biomarkers have seldom been examined, and the relationship between urinary steroid hormones and melatonin is still poorly understood. In most cases, hormones are determined by immunoassays respectively, mainly enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA). There are also reports describing the liquid chromatography with tandem mass spectrometry (LC-MS/MS) technique as a method of melatonin or few steroid hormones quantification, however, the simultaneous detection of multiple rhythmic hormones in human urine is rarely reported. For the quantification of the rhythmic hormones in human urine, an accurate approach using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was devised in this work. Nine endogenous hormones (melatonin, 6-hydroxymelatonin, 6-sulfatoxymelatonin, cortisol, corticosterone, cortisone, testosterone, epitestosterone and androsterone), in human overnight urine, were quantified after solid phase extraction (SPE). A reverse phase HSS C18 column was used for chromatographic separation with a 9-minute gradient elution and deuterated analogues of each analyte were applied as internal standards. This method was successfully applied to the analysis of 596 overnight urine samples (23:00-9:00) collected from 84 air traffic controllers in the Beijing area during shift work. This study's findings showed a clear correlation not only between melatonin and its metabolites; cortisol-related metabolites, but also between melatonin metabolites and endogenous metabolites upstream and downstream of cortisol, implying that these two categories of hormones can be used as potential biological rhythm indicators to provide circadian rhythm data support for future studies on circadian rhythm disorders.

Extraction and quantification of melatonin in cornelian cherry (Cornus mas L.) by ultra-fast liquid chromatography coupled to fluorescence detector (UFLC-FD)

Wild edible plants (WEPs) can be widely found in the world and defined as native species that grow naturally in their natural habitat. They have become part of the traditional food as human diet and used in folk medicine to treat diseases. They are very rich in terms of nutraceuticals. Melatonin is a natural hormone providing several benefits for human health. It has functions such as regulating growth and development and increasing tolerance to environmental stress factors in plants. It is stated that the serum melatonin level in humans increases after intake of foods containing melatonin. This study examined the presence of melatonin in wild grown cornelian cherry fruits by UFLC-FD and determined suitable extraction and chromatographic conditions. The optimum mobile phase, excitation/emission wavelength, and extraction solvent were determined as methanol: water: acetic acid, 275/345 nm, and methanol: water: HCl, respectively. Melatonin content in fruits ranged from 130.82 to 201.84 ng g−1 in fresh fruit.

Grape Seed Proanthocyanidins Mitigate the Disturbances Caused by an Abrupt Photoperiod Change in Healthy and Obese Rats

Variations in the light/dark cycle and obesogenic diets trigger physiological and behavioral disorders. Proanthocyanidins, in addition to their healthy properties, have recently demonstrated a modulating effect on biological rhythms. Therefore, the aim of this study was to evaluate the administration of a grape seed proanthocyanidin-rich extract (GSPE) to mitigate the disruption caused by a sudden photoperiod change in healthy and cafeteria (CAF)-diet obese rats. For this, 48 photoperiod-sensitive Fischer 344 rats were fed standard or CAF diets for 6 weeks under a standard (12 h light/day, L12) conditions. Then, rats were switched to a long (18 h light/day, L18) or short (6 h light/day, L6) photoperiod and administered vehicle or GSPE (25 mg/kg) for 1 week. Body weight (BW) and food intake (FI) were recorded weekly. Animal activity and serum hormone concentrations were studied before and after the photoperiod change. Hormone levels were measured both at 3 h (ZT3) and 15 h (ZT15) after the onset of light. Results showed the impact of the CAF diet and photoperiod on the BW, FI, activity, and hormonal status of the animals. GSPE administration resulted in an attenuation of the changes produced by the photoperiod disruption. Specifically, GSPE in L6 CAF-fed rats reduced serum corticosterone concentration, restoring its circadian rhythm, increased the T3-to-T4 ratio, and increased light phase activity, while under L18, it decreased BW and testosterone concentration and increased the animal activity. These results suggest that GSPE may contribute to the adaptation to the new photoperiods. However, further studies are needed to elucidate the metabolic pathways and processes involved in these events.

Evaluation of acetamiprid and azoxystrobin residues and their hormonal disrupting effects on male rats using liquid chromatography-tandem mass spectrometry

Endocrine-disrupting compounds as pesticides affect the hormonal balance, and this can result in several diseases. Therefore, the analysis of representative hormones with acetamiprid (AC) and azoxystrobin (AZ) was a good strategy for the investigation of the endocrine-disrupting activity of pesticides. Hence, a sensitive and rapid analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The method was validated for the analysis of AC, AZ, estriol, estrone, progesterone, and testosterone in the serum, testis, and liver of rats. The correlation between the residues of pesticides and the disturbance of the endocrine system was evaluated. The different mass parameters, mobile phase types, analytical columns, injection volumes, and extraction solvents were compared to get the lowest limit of detection of the studied compounds. The detection limits of AC, AZ, estriol, estrone, progesterone, and testosterone were 0.05, 0.05, 1.0, 10, and 1.0 ng/ml, respectively. The method developed was applied to evaluate the changes in these hormones induced by the duration of exposure to AC and AZ in rat testis and serum. The hormones level in rat serum and testis had a significant decrease as they were oral gavage treated with different high concentrations of studied pesticides. Both pesticides were distributed in the body of rats by the multi-compartment model (liver, testis, and serum).

Up-to-date studies regarding the determination of melatonin by chromatographic methods

Melatonin is an indolic compound that has been reported in the literature to exist in human-based samples, vertebrates, vegetables, fruits, and pharmaceutical products. Melatonin is considered a dietary supplement and can regulate circadian rhythms, although it has not been classified as a drug by the US Food and Drug Administration. Several analytical methods have been used for its detection. This study aimed to summarize the recent outcomes of the chromatographic methods such as electrophoretic methods, gas chromatography, and liquid chromatography, which have been used for the determination of melatonin in the last three decades, with the focus on gas chromatography and high-performance liquid chromatography methods.

High-throughput quantitation of trace level melatonin in human milk by on-line enrichment liquid chromatography-tandem mass spectrometry

The level of melatonin in human milk might be closely related to infant development and the building up of their circadian rhythms. The large population investigation on this topic would provide insights for the prevention and treatment of diseases related to early development and circadian rhythms. However, it has not been well studied. Trace level endogenous melatonin and difficulties in sample collection are among the challenges limiting the progress. High throughput analytical method with high specificity and sensitivity to determine the endogenous melatonin concentration is highly desired. A newly developed easily operated and high-throughput sensitive on-line enrichment liquid chromatography-tandem mass spectrometry (LC-MS/MS) method would be reported in this paper. Melatonin-d₃ (MEL-d₃) was used as a surrogate standard for the calibration curve and melatonin-d₄ (MEL-d₄) was used as an internal standard. Sample preparation was simply performed in 96-well plate by protein precipitation using acetonitrile (ACN). The supernatant was injected directly into the easily configured LC-MS/MS system with an enlarged sample loop and a mixer. Positive mode multiple reaction monitoring (MRM) was adopted for the measurement of melatonin in milk. 100 μL sample was used for analysis and the calibration curve linear range was 1-1000 pg mL^-1. In three validation batches, the accuracy was within 11.0% deviation from the relative nominal concentration, whereas the intra- and inter-assay precision was ≤4.1% and ≤6.8% relative standard deviation (RSD), respectively. Although matrix effect was observed in the validation experiments, the stable isotope labeled internal standard (MEL-d₄) could correct it and the overall relative matrix effect of MEL-d₃/MEL-d₄ was close to 100%. The overall spike recovery of the method was 101.7% with 5.1% RSD. Compared to currently reported methods, it could reach 1 pg mL^-1 lower limit of quantification (LLOQ) with a smaller sample volume, sample preparation could be easily performed by automated liquid handling system and was more suitable for large population cohort studies on trace level endogenous melatonin determination.

Bioanalytical strategies in drug discovery and development

A reliable, rapid, and effective bioanalytical method is essential for the determination of the pharmacokinetic, pharmacodynamic, and toxicokinetic parameters that inform the safety and efficacy profile of investigational drugs. The overall goal of bioanalytical method development is to elucidate the procedure and operating conditions under which a method can sufficiently extract, qualify, and/or quantify the analyte(s) of interest and/or their metabolites for the intended purpose. Given the difference in the physicochemical properties of small and large molecule drugs, different strategies need to be adopted for the development of an effective and efficient bioanalytical method. Herein, we provide an overview of different sample preparation strategies, analytical platforms, as well as procedures for achieving high throughput for bioanalysis of small and large molecule drugs.

Mass Spectrometry-Based Determination of Thyroid Hormones and Their Metabolites in Endocrine Diagnostics and Biomedical Research – Implications for Human Serum Diagnostics

The wide spectrum of novel applications for the LC-MS/MS-based analysis of thyroid hormone metabolites (THM) in blood samples and other biological specimen highlights the perspectives of this novel technology. However, thorough development of pre-analytical sample workup and careful validation of both pre-analytics and LC-MS/MS analytics, is needed, to allow for quantitative detection of the thyronome, which spans a broad concentration range in these biological samples.

This minireview summarizes recent developments in advancing LC-MS/MS-based analytics and measurement of total concentrations of THM in blood specimen of humans, methods in part further refined in the context of previous achievements analyzing samples derived from cell-culture or tissues. Challenges and solutions to tackle efficient pre-analytic sample extraction and elimination of matrix interferences are compared. Options for automatization of pre-analytic sample-preparation and comprehensive coverage of the wide thyronome concentration range are presented. Conventional immunoassay versus LC-MS/MS-based determination of total and free THM concentrations are briefly compared.

LC-APCI+-MS/MS method for the analysis of ten hormones and two endocannabinoids in plasma and hair from the mice with different gut microbiota

The effect of gut microbiota on the activity of the HPA and HPG axes and ECS is a short-term or long-lasting process remains unclear in rodents. However, the extant studies focused only on its short-term effect on the HPA activity because there is lack of reliable biomarkers characterizing short-term activity of the HPG axis and ECS and long-term activities of the three endocrine systems. The endogenous levels of aldosterone (ALD), 11-dehydrocorticosterone (11-DHC), estradiol (E2), estrone (E1), androstenedione (A4), dihydrotestosterone (DHT), corticosterone (CORT), dehydroepiandrosterone (DHEA), testosterone (T), progesterone (P), N-arachidonoyl ethanoamide (AEA) and 1-arachydonoyl glycerol (1-AG) in hair and plasma are the potential long-term and short-term biomarkers of the three systems. This study aimed to develop the sensitive and selective methods for simultaneous quantitation of the twelve compounds in rodent's hair and plasma. Then the methods were used to explore the differences in the hair levels of the twelve compounds between the mice in XZ group possibly having gut microbiota with more diversity and SPF group possibly having gut microbiota with less diversity and the inter-group differences in the plasma levels in the response to 1-h restraint stress. The methods were based on high performance liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization in positive mode. The methods were adopted for 20 mg hair and 100 μL plasma, respectively. Hair samples were incubated in methanol at 40 ℃ for 24 h, and were performed by solid phase extraction. Plasma samples were implemented by liquid-liquid extraction with ethyl acetate. The methods showed limit of quantification at 0.06-1.3 pg/mg and 0.03-0.6 ng/mL and recovery ranging between 87.7-115.1 % and 86.1-114.6 % for all compounds in rodent's hair and plasma, and the intra-day and inter-day coefficients of variation less than 15 %, and good freeze/thaw and short-term stability. The present methods also had good reliability as demonstrated by the sex difference in the testosterone levels in hair and plasma. The inter-group comparison revealed that the mice in XZ group showed significantly higher hair levels than those in SPF group for 1-AG and most of hormones except for T and P. The non-stressed female mice in SPF showed significantly higher plasma levels than those in XZ for AEA and most of hormones except for E2, A4, DHT, T and 1-AG, but there were no inter-group differences for the stressed mice except for DHEA and 11-DHC and for the non-stressed male mice. Additionally, the stressed mice showed significantly higher corticosterone level in plasma than controls for male and female mice in XZ and male mice in SPF, but it was not true for female mice in SPF.