Simultaneous determination of tryptophan, 5-hydroxytryptophan, tryptamine, serotonin, and 5-HIAA in small volumes of mouse serum using UHPLC-ED.

In this paper we report a simple and efficient method for the concurrent analysis of tryptophan, 5-HTP, tryptamine, serotonin, and 5-HIAA in mouse serum using UHPLC-ED after protein precipitation and dilution. These compounds are neuroactive and are of interest in studies of mood and behavior; They are also biomarkers for the presence of neuroendocrine tumors and are used in the diagnosis of these cancers. After a brief series of validation experiments, this method was applied to serum from mouse behaviour experiments.•A convenient UHPLC method with electrochemical detection for concomitant analysis of the serotonin pathway in serum, including, for the first time, tryptamine.•The method met all performance criteria established for use in our lab and was applied in rodent experiments.

Microbial production of beneficial indoleamines (serotonin and melatonin) with potential application to biotechnological products for human health.

Micro-organisms have showed the ability to produce biologically active compounds associated with neurotransmission in higher organisms. In particular, serotonin- and melatonin-producing microbes are valuable sources for the development of eco-friendly bioproducts. Serotonin and melatonin are indoleamines that have received special attention due to their positive effects on human health. These biomolecules exert a critical role in several physiological or pathological processes, including some mental and neurological disorders. This article includes a review of the microbial production of serotonin and melatonin, their functions in micro-organisms and their potential uses as therapeutic and/or preventive agents to improve human health. A description of the quantification methods employed to detect indoleamines and the evidence found concerning their microbial production at laboratory and industrial scale-for application in biotechnological products-is also provided. The microbial ability to synthesize beneficial indoleamines should be further studied and harnessed, to allow the development of sustainable bioprocesses to produce foods and pharmaceuticals for human health.

Attenuating the adverse aspects of water stress on wheat genotypes by foliar spray of melatonin and indole-3-acetic acid.

Melatonin is important due to its involvement in regulation of diverse mechanisms in plants. Its presence in plants is universal and provides primary defense against environmental stresses. In this study the effect of foliarly applied indole-3-Acetic Acid (IAA) and melatonin (control, 100, 150 µg/g each) on wheat seedling growth under water deficit condition was examined. The mitigation of stress was seen in melatonin treated wheat plants facing abiotic stress, with less accumulation of the H2O2, MDA and anthocyanin. A marked decrease in chlorophyll, total soluble proteins, total soluble sugars, ascorbic acid, phenolic contents and yield- related attributes was noticed in stressed condition. Treatment with melatonin and IAA alleviated stress induced decrease in biochemical attributes, and growth of wheat plants in a dose-dependent manner. A significant increase in yield was achieved by melatonin treatments in Ujala-2016 under limited water supply. It is worthy to mention that melatonin spray at 150 µg/g followed by IAA proved to be the most pronounced treatment in the buildup of osmolytes and regulation of antioxidant defense system with increase in yield under water limited environment.

New insights on neurotransmitters signaling mechanisms in plants.

Neurotransmitters (NTs) such as acetylcholine, biogenic amines (dopamine, noradrenaline, adrenaline, histamine), indoleamines [(melatonin (MEL) & serotonin (SER)] have been found not only in mammalians, but also in diverse living organisms-microorganisms to plants. These NTs have emerged as potential signaling molecules in the last decade of investigations in various plant systems. NTs have been found to play important roles in plant life including-organogenesis, flowering, ion permeability, photosynthesis, circadian rhythm, reproduction, fruit ripening, photomorphogenesis, adaptation to environmental changes. This review will provide an overview of recent advancements on the physiological and molecular mechanism of NTs in plants. Moreover, molecular crosstalk of SER and MEL with various biomolecules is also discussed. The study of these NTs may serve as new understanding of the mechanisms of signal transmission and cell sensing in plants subjected to various environmental stimulus.

Assessment of Tryptophan, Tryptophan Ethylester, and Melatonin Derivatives in Red Wine by SPE-HPLC-FL and SPE-HPLC-MS Methods.

Melatonin (MEL) is an indoleamine produced mainly by the pineal gland in vertebrates. It plays a significant role in the regulation of circadian rhythms, mitigation of sleeping disorders, and jet lag. This compound is synthetized from tryptophan (TRP) and it has been found in seeds, fruits, and fermented beverages, including wine. Wine is also a source of other tryptophan derivatives, the tryptophan ethylester (TEE) and MEL isomers (MISs), for which the biological properties need to be elucidated. An analytical method for the simultaneous quantification of TRP, TEE, and MEL was developed by a Solid Phase Extraction (SPE) of a preconcentration of wine followed by high performance liquid chromatography (HPLC) analysis either with fluorescence or mass spectrometer detectors. The analytical method showed a relative standard deviation (RSD) lower than 8%, except for TRP (RSD 10.5% in wine). The recovery was higher than 76%. The versatility of SPE preconcentrations allowed for the adequate preconcentration of wine sample as well as detection of low concentrations, an important aspect especially for MEL (detection limit 0.0023 µg/L). The proposed method proved to be suitable for assessing the investigated compounds in some red wine samples, where 74.4⁻256.2 µg/L and 0.038⁻0.063 µg/L of TEE and MEL were detected, respectively. Five MISs were also found in wine samples in concentrations up to 1.97 µg/L.

Effect of Red Wine Intake on Serum and Salivary Melatonin Levels: A Randomized, Placebo-Controlled Clinical Trial.

Melatonin (MLT) is a recently discovered phytochemical in wine, but its influence on physiological MLT levels is still unknown. This study aimed at evaluating variations, in serum and saliva, of MLT concentrations after the intake of MLT-enriched red wine. Twelve healthy volunteers were recruited to receive 125 mL of red wine naturally lacking of MLT (placebo, PLC), or the same wine enriched with MLT (MLT+). A physiological steady decline of serum MLT was observed from baseline up to 90 min, for both wines. After PLC intake, the decrease was significantly faster than the one occurring after MLT+ wine, which thus delayed the drop down of serum MLT with a plateau at 30⁻60 min. Salivary MLT levels slightly peaked at 45 min after MLT+ wine intake, without statistical significance. Therefore, the intake of a glass of MLT-enriched red wine changed serum levels of the indoleamine, supporting the role of wine MLT in counteracting the physiological decline of the hormone into the bloodstream.

Fetal growth-retardation and brain-sparing by malnutrition are associated to changes in neurotransmitters profile.

The present study assesses possible changes in the levels of different neurotransmitters (catecholamines and indoleamines) in fetuses affected by nutrient shortage. Hence, we determined the concentration of catecholamines and indoleamines at the hypothalamus of 56 swine fetuses obtained at both 70 and 90days of pregnancy (n=33 and 23 fetuses, respectively). The degree of fetal development and the fetal sex affected the neurotransmitters profile at both stages. At Day 70, there were found higher mean concentrations of l-DOPA in both female and male fetuses with severe IUGR; male fetuses with severe IUGR also showed higher concentrations of TRP than normal male littermates. At Day 90 of pregnancy, the differences between sexes were more evident. There were no significant effects from either severe IUGR on the neurotransmitter profile in male fetuses. However, in the females, a lower body-weight was related to lower concentrations of l-DOPA and TRP and those female fetuses affected by severe IUGR evidenced lower HVA concentration. In conclusion, the fetal synthesis and use of neurotransmitters increase with time of pregnancy but, in case of IUGR, both catecholamines and indoleamines pathways are affected by sex-related effects.

Sex and intrauterine growth restriction modify brain neurotransmitters profile of newborn piglets.

The current study aimed to determine, using a swine model of intrauterine growth restriction (IUGR), whether short- and long-term neurological deficiencies and interactive dysfunctions of Low Birth-Weight (LBW) offspring might be related to altered pattern of neurotransmitters. Hence, we compared the quantities of different neurotransmitters (catecholamines and indoleamines), which were determined by HPLC, at brain structures related to the limbic system (hippocampus and amygdala) in 14 LBW and 10 Normal Body-Weight (NBW) newborn piglets. The results showed, firstly, significant effects of sex on the NBW newborns, with females having higher dopamine (DA) concentrations than males. The IUGR processes affected DA metabolism, with LBW piglets having lower concentrations of noradrenaline at the hippocampus and higher concentrations of the DA metabolites, homovanillic acid (HVA), at both the hippocampus and the amygdala than NBW neonates. The effects of IUGR were modulated by sex; there were no significant differences between LBW and NBW females, but LBW males had higher HVA concentration at the amygdala and higher concentration of 5-hydroxyindoleacetic acid, the serotonin metabolite, at the hippocampus than NBW males. In conclusion, the present study shows that IUGR is mainly related to changes, modulated by sex, in the concentrations of catecholamine neurotransmitters, which are related to adaptation to physical activity and to essential cognitive functions such as learning, memory, reward-motivated behavior and stress.

Non-invasive screening for neuroendocrine tumors-Biogenic amines as neoplasm biomarkers and the potential improvement of "gold standards".

Early, noninvasive diagnosis of tumors is relevant, especially for rare, often asymptomatic, thus - hard to detect in curable stages of the disease - tumors, as neuroendocrine tumors (NET). To avoid or supplement the NET management via application of invasive biopsy or expensive imagining techniques, the biochemical evaluation of biomarkers from easy accessible body fluids could be the great, potential diagnostic or prognostic tool. Nevertheless, already existed biochemical diagnostic tools for NET must be improved. Biogenic amines' (BA) determination in biological samples is significant for the description of the most NET, such as pheochromocytoma, neuroblastoma or carcinoid tumor. The bioanalytical approaches applied for the analysis of BA concentration in patient's body fluids still are required to be improved. It is caused by the low BA levels in real samples, their distinct physiochemical properties, light sensitiveness and easy degradation in the presence of oxygen, among others. Moreover, the interpretation of single analyte result is not clinically sufficient recently and more precise biomarkers or - more ideally - panels of several biomarkers are considered to be simultaneously measured and analyzed. Therefore, the NET-management "gold standards" can be routinely modified. Accordingly, presented review will focus on the recent status of BA analysis treated as the potential biomarker in terms of analytical method development applied for the real patients' samples analysis. Furthermore, the main advantages of current dominance of panel of biomarkers analysis for the NET patients diagnosis, follow up and monitoring of the therapy, will be underlined.

Melatonin in Mediterranean diet, a new perspective.

The health-promoting properties of the Mediterranean diet have been attributed, at least in part, to the chemical diversity of plant foods. Among phytochemicals, polyphenols represent the paradigm of the relationship between healthy foods and reduced risk of chronic-degenerative diseases, although, in the past few years, a new element has enriched this scenario. Melatonin, and possibly other indoleamines recently discovered in some relevant Mediterranean foods, may represent a new factor contributing to the elucidation of the protective effects of diets rich in plant products. Therefore, in synergy with polyphenols and other bioactive phytochemicals (e.g. carotenoids and glucosinolates), melatonin may contribute to maximizing the benefits of healthy dietary styles. This brief survey deals with the occurrence of melatonin in the Mediterranean diet, with an emphasis on grape products, and focuses on the biological significance of dietary melatonin, an emerging and exciting topic in the field of nutritional sciences.

Sex-dependent and non-monotonic enhancement and unmasking of methylmercury neurotoxicity by prenatal stress.

Methylmercury (MeHg) and prenatal stress (PS) are risk factors for neurotoxicity that may co-occur in human populations. Because they also share biological substrates and can produce common behavioral deficits, this study examined their joint effects on behavioral and neurochemical effects in male and female rats. Dams had access to 0, 0.5 or 2.5ppm MeHg chloride drinking water from two to three weeks prior to breeding through weaning. Half of the dams in each of these treatment groups also underwent PS on gestational days 16-17. This yielded 6 groups/gender: 0-NS, 0-PS, 0.5-NS, 0.5-PS, 2.5-NS, and 2.5-PS. Behavioral testing began in young adulthood and included fixed interval (FI) schedule-controlled behavior, novel object recognition (NOR) and locomotor activity, behaviors previously demonstrated to be sensitive to MeHg and/or mediated by brain mesocorticolimbic dopamine glutamate systems targeted by both MeHg and PS. Behavioral deficits were more pronounced in females and included impaired NOR recognition memory only under conditions of combined MeHg and PS, while non-monotonic reductions in FI response rates occurred, with greatest effects at the 0.5ppm concentration; the less reduced 2.5ppm FI response rates were further reduced under conditions of PS (2.5-PS). Correspondingly, many neurochemical changes produced by MeHg were only seen under conditions of PS, particularly in striatum in males and in hippocampus and nucleus accumbens in females, regions of significance to the mediation of FI and NOR performance. Collectively these findings demonstrate sex-dependent and non-monotonic effects of developmental MeHg exposure that can be unmasked or enhanced by PS, particularly for behavioral outcomes in females, but for both sexes in neurochemical changes, that were observed at MeHg exposure concentrations that did not influence either reproductive outcomes or maternal behavior. Thus, assessment of risks associated with MeHg may be underestimated in the absence of other extant risk factors with which it may share common substrates and effects.

The structurally related auxin and melatonin tryptophan-derivatives and their roles in Arabidopsis thaliana and in the human malaria parasite Plasmodium falciparum.

Indole compounds are involved in a range of functions in many organisms. In the human malaria parasite Plasmodium falciparum, melatonin and other tryptophan derivatives are able to modulate its intraerythrocytic cycle, increasing the schizont population as well as parasitemia, likely through ubiquitin-proteasome system (UPS) gene regulation. In plants, melatonin regulates root development, in a similar way to that described for indoleacetic acid, suggesting that melatonin and indoleacetic acid could co-participate in some physiological processes due to structural similarities. In the present work, we evaluate whether the chemical structure similarity found in indoleacetic acid and melatonin can lead to similar effects in Arabidopsis thaliana lateral root formation and P. falciparum cell cycle modulation, as well as in the UPS of gene regulation, by qRT-PCR. Our data show that P. falciparum is not able to respond to indoleacetic acid either in the modulation of the intraerythrocytic cycle or in the gene regulation mediated by the UPS as observed for melatonin. The similarities of these indole compounds are not sufficient to confer synergistic functions in P. falciparum cell cycle modulation, but could interplay in A. thaliana lateral root formation.