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The purpose of this work was to investigate, for the first time to our knowledge, the chemical composition and bioactivity of methanolic extracts (roots, stems, leaves, and flowers) from Cladanthus mixtus (L.) Chevall. that grows wild in northern Morocco (the Tangier-Tetouan-Al Hoceima region). The phenolic and flavonoid contents were determined by spectrophotometer methods, and the composition of derivatized methanolic extracts from C. mixtus using N - O -bis(trimethylsilyl) trifluoroacetamide (BSTFA) was analyzed by gas chromatography-mass spectrometry (GC-MS). The antioxidant activity was carried out by applying the 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and DPPH (2,2-diphenyl-1-picrylhydrazyl) tests. The micro-dilution technique was chosen to investigate the antimicrobial activity of methanolic extracts against two bacterial strains and three fungal species. The results showed that the values of total phenolic and flavonoid contents were found to be higher in flower extracts (30.55 ± 0.85 mg of gallic acid equivalents (GAE)/g of dried weight (DW) and 26.00 ±1.34 mg of quercetin equivalents (QE)/g DW, respectively). Other groups of chemical compounds were revealed by GC-MS, such as carbohydrates (27.25-64.87%), fatty acids (1.58-9.08%), organic acids (11.81-18.82%), and amino acids (1.26-7.10%). Root and flower methanolic extracts showed the highest antioxidant activity using ABTS (39.49 mg of Trolox equivalents (TE)/g DW) and DPPH (36.23 mg TE/g DW), respectively. A positive correlation between antioxidant activity and polyphenol and flavonoid amounts was found. Antibacterial tests showed that the best activity was presented by the leaf extract against Staphylococcus aureus (minimum inhibitory concentration (MIC) = minimum bactericidal concentration (MBC) = 20 mg/mL) and Escherichia coli (MIC of 30 mg/mL and MBC of 35 mg/mL). S. aureus was more sensitive to the extracts compared to E. coli . All extracts showed antifungal activity against Trichophyton rubrum , with the best efficacy reported by the flower and leaf extracts (MIC = 1.25 mg/mL and minimum fungicidal concentration (MFC) = 2.5 mg/mL). In general, extracts of C. mixtus appeared less effective against Candida albicans and Aspergillus fumigatus .

Introduction: Most of the pregnant women do not achieve the recommended dietary intake of vitamins A and E. These vitamins may counteract oxidative stress involved in some adverse perinatal outcomes. We aimed to assess the associations between maternal vitamin A and E at mid-pregnancy with both maternal and fetal outcomes and to identify possible early biomarkers during pregnancy to predict and prevent oxidative stress in the offspring., Methods: Data on dietary and serum levels of vitamins A and E were collected from 544 pregnant women from the Nutrition in Early Life and Asthma (NELA) study, a prospective mother-child cohort set up in Spain., Results: There were large discrepancies between low dietary vitamin E intake (78% of the mothers) and low serum vitamin E levels (3%) at 24 weeks of gestation. Maternal serum vitamins A and E at mid-pregnancy were associated with higher antioxidant status not only in the mother at this time point (lower hydroperoxides and higher total antioxidant activity [TAA]) but also with the newborn at birth (higher TAA). Gestational diabetes mellitus (GDM) was negatively associated with maternal serum vitamin A (OR: 0.95 CI: 0.91-0.99, p = 0.009) at mid-pregnancy. Nevertheless, we could not detect any association between GDM and oxidative stress parameters., Conclusions: In conclusion, maternal vitamin A and E serum levels may be used as an early potential biomarker of antioxidant status of the neonate at birth. Control of these vitamins during pregnancy could help avoid morbid conditions in the newborn caused by oxidative stress in GDM pregnancies., (© 2023 S. Karger AG, Basel.)

Harsh or extreme environmental conditions largely determine the vegetative and reproductive development of plants. In the case of cultivated plants, their growth and yield are clearly diminished if they are exposed to severe conditions such as drought, waterlogging, extreme heat or cold, UV radiation, or toxic substances in the soil such as salts, heavy metals and pesticides. Melatonin has been studied for decades as a molecule capable of reducing the negative effects of abiotic stressors by increasing tolerance to these adverse growth conditions. This work presents a review of the most outstanding studies with various plant species in each of the above-mentioned stress situations, including proteomic and post-translational studies. Melatonin mediates plant responses to abiotic stress, generally inducing an antioxidative response, and also regulating a complex gene response adapted to individual stressors. Plants are able to increase their endogenous melatonin levels through the application of exogenous melatonin or through the inductive mechanism of endogenous melatonin biosynthesis. In such ways, plants are able to cope with the stressful situation at hand, accommodating their metabolism, morphology and physiology in order to increase overall survival and induce greater tolerance to stress. The agronomic implications of the use of melatonin are discussed., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Melatonin ( N -acetyl-5-methoxytryptamine) is a nontoxic biological molecule produced in a pineal gland of animals and different tissues of plants. It is an important secondary messenger molecule, playing a vital role in coping with various abiotic and biotic stresses. Melatonin serves as an antioxidant in postharvest technology and enhances the postharvest life of fruits and vegetables. The application of exogenous melatonin alleviated reactive oxygen species and cell damage induced by abiotic and biotic stresses by means of repairing mitochondria. Additionally, the regulation of stress-specific genes and the activation of pathogenesis-related protein and antioxidant enzymes genes under biotic and abiotic stress makes it a more versatile molecule. Besides that, the crosstalk with other phytohormones makes inroads to utilize melatonin against non-testified stress conditions, such as viruses and nematodes. Furthermore, different strategies have been discussed to induce endogenous melatonin activity in order to sustain a plant system. Our review highlighted the diverse roles of melatonin in a plant system, which could be useful in enhancing the environmental friendly crop production and ensure food safety.

Background: White tea infusion (Camelia sinensis) has antioxidants properties. The infusion contains polyphenols that have been proposed to induce antioxidant response element (ARE) response via nuclear factor E2-related factor 2 (NRF2). Adriamycin (ADR) has antitumour properties and oxidative effects. Oxidative stress is related to a variety of kidney diseases. Prevention of the oxidative stress through long-term intake of white tea and the study of the molecular mechanisms involved in protection could be of great interest. Rats were given distilled water, 0.015 or 0.045 g of solid white tea extract kg(-1) body weight for 12 months. Animals received an injection of ADR. In kidney, oxidative stress parameters were measured, the expressions of nuclear factor E2-related factor 2 gene (Nrf2), and detoxifying and antioxidants genes were analysed, and the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) were measured., Results: ADR administration increased oxidative parameters and decreased the antioxidant activity; significantly increased the expression of analysed genes and the activity of CAT and SOD and decreased GR activity. The highest white tea dose protected redox status and inhibited ARE response., Conclusion: Long-term intake of white tea protected kidney against the oxidative stress. ADR activated the ARE response but in animals treated with the highest dose of white tea, this response was inhibited, probably for antioxidant protection. © 2015 Society of Chemical Industry., (© 2015 Society of Chemical Industry.)

Melatonin regulates the growth of roots, shoots, and explants, to activate seed germination and rhizogenesis and to delay induced leaf senescence. The antioxidant properties of melatonin would seem to explain, at least partially, its ability to fortify plants subjected to abiotic stress. In this Review we examine recent data on the gene-regulation capacity of melatonin that point to many interesting features, such as the upregulation of anti-stress genes and recent aspects of the auxin-independent effects of melatonin as a plant growth regulator. This, together with the recent data on endogenous melatonin biosynthesis induction by environmental factors, makes melatonin an interesting candidate for use as a natural biostimulating treatment for field crops., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: Melatonin, an indoleamine well known in vertebrates and structurally related to other important substances such as tryptophan or indole-3-acetic acid, is also present in the plant kingdom although its specific function(s) remain to be established. The emerging field of melatonin studies in plants has progressed very slowly, mainly due to the problems associated with melatonin quantification in plants., Objective: Two commonly used procedures for plant samples are compared. The analytical characteristics of both procedures are quantitatively presented using different solvents and small amounts of fresh biological material, and the respective recovery rates and quantitative limits are presented. Some improvements are suggested., Methodology: Two different sample extraction procedures were compared: a direct-sample extraction (DSE) and a homogenised- sample extraction (HSE). Melatonin was then determined in the respective plant samples by HPLC with fluorescence detection., Results: Using the DSE procedure, more than 94% melatonin was recovered from standard solutions, whereas levels higher than 93% were recovered from the spiked plant samples, with little difference between ethyl acetate and chloroform extractions. In the case of HSE, the recoveries of melatonin were approximately half and never higher than 55%. The ultrasonic treatment proposed in the DSE procedure showed different levels of efficiency (2-20%), depending on the sample., Conclusion: This study has established that, with the direct sample extraction procedure, higher recovery rates are obtained both in standard solutions and in plant samples. The straightforwardness and reproducibility of the extraction procedure is accompanied by the high sensitivity obtained with fluorescence detection.

The steady-state of reactive oxygen species (ROS) in plant cells is controlled by ROS-producing and scavenging agents. A large cellular pool of antioxidant metabolites is involved in their control. Variations in this antioxidant pool may be monitored by measuring changes in hydrophilic antioxidant activity (free radical-quenching activity of water-soluble components) and ascorbic acid levels. The de-etiolation process and induction of light stress in Avena sativa and Triticum aestivum leaves were used as physiological models to study the antioxidant status at different ages. The data showed that five-day-old green plants and de-etiolated plants of the same age have similar hydrophilic antioxidant activity ( approximately 8 mumol ASC equivalents g FW(-1)), which increases during the de-etiolation process. In oat and wheat, young leaves (five days old) had higher antioxidant status (hydrophilic antioxidant activity and ascorbic acid level) than old leaves (10 and 20 days old). High-light treatment caused a decrease in antioxidant status, especially in young leaves. Hydrophilic antioxidant activity and ascorbic acid levels recovered totally or partially after 30 or 60 min in the dark. This capacity also depends on age and species. The ascorbic acid/hydrophilic antioxidant activity ratio is presented as an indicator of antioxidant variations in response to stress, but taking into account the absolute levels of antioxidants.

The 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid)/H2O2/horseradish peroxidase (ABTS/H2O2/HRP) decoloration method permits the evaluation of the antioxidant activity of complex food samples. This method is capable of determining both hydrophilic (in buffered media) and lipophilic (in organic media) antioxidant properties in the same sample. Its application to the study of the antioxidant properties of grapes, one white and two black, has permitted us to establish important differences in the antioxidant activity. The black grapes showed higher antioxidant activity than the white variety. The determination of hydrophilic antioxidant activity (HAA) and lipophilic antioxidant activity (LAA) in the three grapes showed that a minor contribution (4-13%) of total antioxidant activity (TAA) was due to LAA in all cases. The experimentally determined HAA could be approximated using the relative contributions of the calculated values of reference compounds (total phenols as gallic acid and anthocyanins as malvidin).

The ABTS/H(2)O(2)/HRP decoloration method is capable of determining both hydrophilic (in buffered media) and lipophilic (in organic media) antioxidant properties in complex samples. Now, we have adapted this method for on-line chromatographic determination. The easy, rapid and controlled generation of the ABTS radical and its great stability in buffered and organic media were important characteristics in the measurement of antioxidant activities. The HPLC-ABTS method used two pumps (one for isocratic eluting-phase and the other for preformed ABTS radical) and an UV-VIS diode array detector. The dual analysis of samples -- conventional (with UV-VIS detection) and ABTS-scavenging (at 600 nm) -- provided valuable on-line information about the correspondence between the presence of a determined compound and its possible antioxidant activity, and was applicable to both hydrophilic and lipophilic antioxidants (HAA and LAA). A comparison between HAA and LAA determined by the end-point method and by the on-line HPLC method is presented. The application to juices showed that both methods are suitable, sensitive and selective, gave similar values, and the HPLC-ABTS method contributed additional information about the antioxidant activity profile.

Introduction: Low dietary intake of vitamin E is a global public health issue. RRR-α-tocopherol (RRR-αT) is the only naturally occurring vitamin E stereoisomer, but the equimolecular mixture of all eight stereoisomers, synthetic vitamin E (S-αT), is commonly consumed. The objective of this study was to evaluate bioavailability and antioxidant activity of RRR-αT versus S-αT, in both mother and fetus, after maternal supplementation during pregnancy. Methods: Female rats (7 weeks of age) received a modified AIN-93G diet supplemented with 75 IU/kg of RRR-αT (NVE, n = 20) or S-αT (SVE, n = 17). At delivery, the levels of αT, stereoisomer distribution, and antioxidant capacity were analyzed in maternal and fetal plasma. Results: NVE administration significantly increased the proportion of RRR-αT stereoisomer in maternal and fetal plasma. The percentage of RRR-αT increased from 32.76% to 88.33% in maternal plasma, and 35.25% to 97.94% in fetal plasma, in the NVE group compared to SVE. Fetal plasma from the NVE group was found to have higher total antioxidant capacity compared to SVE. Lastly, fetal plasma RRR-αT stereoisomer percentage was positively associated with expression levels of scavenger receptor class B type 1 (SR-B1) in the placenta. Conclusions: Both natural and synthetic sources of vitamin E showed similar bioavailability. Still, NVE supplementation increased the proportion of RRR-αT and promoted higher antioxidant activity in fetal plasma at birth. Placental SR-B1 might be involved in the stereoselective transfer of RRR-αT stereoisomer across the placenta and may improve αT bioactivity in the fetus. [ABSTRACT FROM AUTHOR]

ABTS (2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid) is a widely used compound for determining the total antioxidant capacity (TAC) of plant extracts, food, clinical fluids, etc. This photometric assay is based on the reduction by the presence of antioxidant compounds of a well-known metastable radical ( A B T S • + ) which can be formed via several different approaches and be used in many different determination methodologies such as automated photometric measures in microplates, clinical robots, valuable titrations, and previous liquid chromatographic separation. Another interesting aspect is that, in some cases, the ABTS/TAC method permits sequential hydrophilic and lipophilic antioxidant activity determinations, obtaining total antioxidant activity values through the summatory data of both types of antioxidants. In this work, we present a review of several aspects of the ABTS/TAC, highlighting the major achievements that have made this method so widely used, e.g., ABTS radical formation in hydrophilic or lipophilic reaction media, measurement strategies, automatization, and adaptation to high-throughput systems, as well as the pros and cons. Moreover, some recent examples of ABTS/TAC method applications in plant, human, and animal samples are discussed. [ABSTRACT FROM AUTHOR]

Biotic stress causes immense damage to agricultural products worldwide and raises the risk of hunger in many areas. Plants themselves tolerate biotic stresses via several pathways, including pathogen-associated molecular patterns (PAMPs), which trigger immunity and plant resistance (R) proteins. On the other hand, humans use several non-ecofriendly methods to control biotic stresses, such as chemical applications. Compared with chemical control, melatonin is an ecofriendly compound that is an economical alternative strategy which can be used to protect animals and plants from attacks via pathogens. In plants, the bactericidal capacity of melatonin was verified against Mycobacterium tuberculosis, as well as multidrug-resistant Gram-negative and -positive bacteria under in vitro conditions. Regarding plant-bacteria interaction, melatonin has presented e ective antibacterial activities against phytobacterial pathogens. In plant-fungi interaction models, melatonin was found to play a key role in plant resistance to Botrytis cinerea, to increase fungicide susceptibility, and to reduce the stress tolerance of Phytophthora infestans. In plant-virus interaction models, melatonin not only e°Ciently eradicated apple stem grooving virus (ASGV) from apple shoots in vitro (making it useful for the production of virus-free plants) but also reduced tobacco mosaic virus (TMV) viral RNA and virus concentration in infected Nicotiana glutinosa and Solanum lycopersicum seedlings. Indeed, melatonin has unique advantages in plant growth regulation and increasing plant resistance e ectiveness against di erent forms of biotic and abiotic stress. Although considerable work has been done regarding the role of melatonin in plant tolerance to abiotic stresses, its role in biotic stress remains unclear and requires clarification. In our review, we summarize the work that has been accomplished so far; highlight melatonin's function in plant tolerance to pathogens such as bacteria, viruses, and fungi; and determine the direction required for future studies on this topic. [ABSTRACT FROM AUTHOR]

Melatonin (N-acetyl-5-methoxytryptamine) was discovered in plants in 1995, while salicylic acid was the name given to the active ingredient of willow in 1838. From a physiological point of view, these two molecules present in plants have never been compared, even though they have a great number of similarities, as we shall see in this work. Both molecules have biosynthesis pathways that share a common precursor and both play a relevant role in the physiology of plants, especially in aspects related to biotic and abiotic stress. They have also been described as biostimulants of photosynthetic processes and productivity enhancers in agricultural crops. We review the coincident aspects of both molecules, and propose an action model, by which the relationship between these molecules and other agents and plant hormones can be studied. [ABSTRACT FROM AUTHOR]

Melatonin, an indoleamine, which has recently been assigned several roles in plant physiology as a growth promoter, as rooting agent, and as antioxidant in senescence delay and cytoprotection, seems to have a relevant function in plant stress situations. The presence of melatonin increases the resistance of lupin plant tissues ( Lupinus albus L.) against natural or artificially induced adverse situations. In this work, we studied the response of lupin plants in controlled stress situations (drought-, anaerobic-, p H-, and cold stress and using ZnSO4, NaCl, and H2O2 as chemical stressors) and measured the changes in endogenous melatonin levels in lupin plants. Also, the effect of abscisic acid, ethylene, and natural environmental conditions were evaluated. In general, nearly all stressful factors caused an increase in melatonin in the investigated organs. The chemical stress provoked by ZnSO4 or NaCl caused the most pronounced changes in the endogenous level of melatonin, followed by cold and drought stressors. In some cases, the level of melatonin increased 12-fold with respect to the levels in control plants, indicating that melatonin biosynthesis is upregulated in common stress situations, in which it may serve as a signal molecule and/or as a direct antistress agent due to its well-known antioxidative properties. [ABSTRACT FROM AUTHOR]

Indolic compounds are a broad family of substances present in microorganisms, plants and animals. They are mainly related with tryptophan metabolism, and present particularities that depend on their respective chemical structures. The most important members of the family are the plant hormone, indole-3-acetic acid, and the animal hormone, melatonin. An important characteristic of some indolic compounds is that they may be useful as chemical preventive agents against diseases such as cancer, oxidative stress, etc. For this reason, the possible antioxidant activities (free radical-scavenging activity) of several indoles were studied. The2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid /H2O2/HRP decoloration method was applied to determine both hydrophilic (in buffered media) and lipophilic (in organic media) antioxidant properties of the indolic compounds. Also, a study of the hydrophilic antioxidant activities of indoles at different pH values (between 4.5 and 8.5) was made. Finally, their possible role as diet plant antioxidants is discussed. [ABSTRACT FROM AUTHOR]

Melatonin (MT) is a pleiotropic molecule with diverse and numerous actions both in plants and animals. In plants, MT acts as an excellent promotor of tolerance against abiotic stress situations such as drought, cold, heat, salinity, and chemical pollutants. In all these situations, MT has a stimulating effect on plants, fomenting many changes in biochemical processes and stress-related gene expression. Melatonin plays vital roles as an antioxidant and can work as a free radical scavenger to protect plants from oxidative stress by stabilization cell redox status; however, MT can alleviate the toxic oxygen and nitrogen species. Beyond this, MT stimulates the antioxidant enzymes and augments antioxidants, as well as activates the ascorbate–glutathione (AsA–GSH) cycle to scavenge excess reactive oxygen species (ROS). In this review, we examine the recent data on the capacity of MT to alleviate the effects of common abiotic soil stressors, such as salinity, alkalinity, acidity, and the presence of heavy metals, reinforcing the general metabolism of plants and counteracting harmful agents. An exhaustive analysis of the latest advances in this regard is presented, and possible future applications of MT are discussed. [ABSTRACT FROM AUTHOR]

Water stress (drought and waterlogging) is severe abiotic stress to plant growth and development. Melatonin, a bioactive plant hormone, has been widely tested in drought situations in diverse plant species, while few studies on the role of melatonin in waterlogging stress conditions have been published. In the current review, we analyze the biostimulatory functions of melatonin on plants under both drought and waterlogging stresses. Melatonin controls the levels of reactive oxygen and nitrogen species and positively changes the molecular defense to improve plant tolerance against water stress. Moreover, the crosstalk of melatonin and other phytohormones is a key element of plant survival under drought stress, while this relationship needs further investigation under waterlogging stress. In this review, we draw the complete story of water stress on both sides—drought and waterlogging—through discussing the previous critical studies under both conditions. Moreover, we suggest several research directions, especially for waterlogging, which remains a big and vague piece of the melatonin and water stress puzzle. [ABSTRACT FROM AUTHOR]

Changes in antioxidant activity during the on-vine ripening of tomatoes (Lycopersicon esculentum) were studied at four different ripening stages (green, breaker, pink and red ripe). Hydrophilic and lipophilic antioxidant activities (HAA and LAA, respectively) were determined and their relationships to ascorbic acid, total phenols, lycopene and β-carotene contents were analysed. HAA and ascorbic acid remained practically unchanged, while the levels of aqueous phenols increased during ripening. The levels of ascorbic acid and HAA were strongly correlated (r=0.90, P<0.1). β-Carotene increased until breaker and pink stages, decreasing afterwards. In contrast, lycopene accumulated throughout the ripening period. The LAA followed the same pattern as lycopene and a good correlation was found (r=0.91, P<0.05). There was less difference between the measured and calculated LAA as the lycopene level increased, the discrepancy being lowest at the red-ripe stage, indicating the importance of lycopene as a lipophilic antioxidant in tomatoes. [Copyright &y& Elsevier]