Mechanisms of Plant Antioxidants Action

A special issue of Plants (ISSN 2223-7747). This special issue belongs to the section "Phytochemistry".

Deadline for manuscript submissions: closed (31 July 2020) | Viewed by 62274

Special Issue Editor

Special Issue Information

Dear Colleagues,

Plants kingdom have always play a vital role for the isolation, identification and modification of compounds able to perform health promoting properties on live organisms.

Moreover, antioxidants are important components in the mechanism of signalling and defence of the same plant, where they are precursors of compounds of greater complexity, modulator of plant growth, as well as defensive system against pathogenic organisms and predators. The extraordinary variety of chemical structure and substitution present in the different plants antioxidant, make them an inestimable source of interesting compounds able to counteract reactive oxygen/nitrogen species (ROS/RNS) and to stimulate the activation of signal cascade inside the cells. The mechanism by which they detoxify this dangerous compounds are complex and involved both direct or indirect interaction with radicals. Antioxidants inhibit or quench free radical reactions mainly based on their reducing capacity or hydrogen atom donating capacity, but also solubility and chelating properties have a remarkable importance in the process, as well as their ability to modulated key metabolic enzymes and activation/block of genes transcription. Taking into accounts the high interest in plant antioxidants as an emerging challenge for the  development of health promoting compounds and potential  biotechnological applications, this Special Issue will cover a wide variety of areas, aiming to contribute to the overall knowledge of molecular mechanism of antioxidants action by multiple point of view on both in the producers and in the consumers.

Prof. Davide Barreca
Guest Editor

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Keywords

  • antioxidants
  • polyphenols
  • free radicals
  • carotenoids
  • vitamins
  • flavonoids
  • activation/block of signal cascade
  • antioxidant modulation of key metabolic enzymes
  • oxidative stress
  • hydrogen atom transfer, single electron transfer
  • antioxidant assays

Published Papers (12 papers)

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Editorial

Jump to: Research, Review

4 pages, 196 KiB  
Editorial
Mechanisms of Plant Antioxidants Action
by Davide Barreca
Plants 2021, 10(1), 35; https://0-doi-org.brum.beds.ac.uk/10.3390/plants10010035 - 25 Dec 2020
Cited by 18 | Viewed by 3101
Abstract
The plant kingdom is a rich source of health-promoting compounds and has always played a fundamental role in the isolation, identification, and modification of compounds able to perform several properties on live organisms. Among them, the so-called “antioxidants” have a major potentiality to [...] Read more.
The plant kingdom is a rich source of health-promoting compounds and has always played a fundamental role in the isolation, identification, and modification of compounds able to perform several properties on live organisms. Among them, the so-called “antioxidants” have a major potentiality to increase human wellness. Antioxidants are important components in the signaling and defense mechanisms in some plants, where they are precursors of compounds of greater complexity, the modulator of plant growth, and the defensive system against pathogenic organisms and predators. The extraordinary variety of chemical structure and substitution present in the different plant antioxidants make them an inestimable source of interesting compounds, with the ability to counter reactive oxygen/nitrogen species (ROS/RNS) and to stimulate the activation of signal cascade inside the cells. The mechanisms by which antioxidants detoxify these dangerous compounds are complex and involve either direct or indirect interaction with radicals. Antioxidants inhibit or quench free radical reactions mainly based on their reducing capacity or hydrogen atom-donating capacity, their solubility, and chelating properties. Moreover, their ability to modulate key metabolic enzymes and activate/block gene transcription also has remarkable importance. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)

Research

Jump to: Editorial, Review

17 pages, 1950 KiB  
Article
Melatonin Counteracts Drought Induced Oxidative Damage and Stimulates Growth, Productivity and Fruit Quality Properties of Tomato Plants
by Mohamed F. M. Ibrahim, Ola H. Abd Elbar, Reham Farag, Mohamed Hikal, Amr El-Kelish, Ahmed Abou El-Yazied, Jawaher Alkahtani and Hany G. Abd El-Gawad
Plants 2020, 9(10), 1276; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9101276 - 28 Sep 2020
Cited by 73 | Viewed by 3800
Abstract
Melatonin “N-Acetyl-5-methoxytryptamine” (MT) has recently been considered as a new plant growth regulator with multiple physiological functions. Although many previous studies have confirmed that exogenous applied-MT can alleviate the deleterious effects of drought stress in many plant species, most of these [...] Read more.
Melatonin “N-Acetyl-5-methoxytryptamine” (MT) has recently been considered as a new plant growth regulator with multiple physiological functions. Although many previous studies have confirmed that exogenous applied-MT can alleviate the deleterious effects of drought stress in many plant species, most of these studies were exclusive on seeds, seedlings, and young plants for a short period of their life cycles. Therefore, the knowledge of using MT as a potential promising agricultural foliar application to improve crop productivity and quality is still insufficient under adverse open field conditions. In this study, we investigated the effect of MT as a foliar application at 0, 20, and 40 ppm on tomato plants that were grown in the open field under the long term of optimal and deficit irrigation conditions. The results indicated that exogenous MT significantly enhanced plant growth, chlorophyll and activities of antioxidant enzymes, including ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POX). This improvement was associated with a marked reduction in proline and soluble sugars. In addition, applied-MT worked as a protective agent against oxidative damage by reducing the cellular content of toxic substances such as H2O2 and malondialdehyde (MDA). Similarly, MT-treated plants showed greater total fruit yield with improving its quality attributes like total soluble solids (TSS), ascorbic acid, and lycopene. Generally, the highest significant fruit yield either under well-watered (13.7%) or water deficit (37.4%) conditions was achieved by the treatment of 20 ppm MT. These results indicate that exogenous MT played an essential role in enhancing tomato tolerance to deficit irrigation and could be recommended as a promising agricultural treatment under such conditions. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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18 pages, 3454 KiB  
Article
Comparative Metabolomics Profiling of Polyphenols, Nutrients and Antioxidant Activities of Two Red Onion (Allium cepa L.) Cultivars
by Rita Metrani, Jashbir Singh, Pratibha Acharya, Guddadarangavvanahally K. Jayaprakasha and Bhimanagouda S. Patil
Plants 2020, 9(9), 1077; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9091077 - 21 Aug 2020
Cited by 41 | Viewed by 5921
Abstract
Onion is among the most widely cultivated and consumed economic crops. Onions are an excellent dietary source of polyphenols and nutrients. However, onions phytonutrient compositions vary with cultivars and growing locations. Therefore, the present study involved the evaluation of polyphenol, nutritional composition (proteins, [...] Read more.
Onion is among the most widely cultivated and consumed economic crops. Onions are an excellent dietary source of polyphenols and nutrients. However, onions phytonutrient compositions vary with cultivars and growing locations. Therefore, the present study involved the evaluation of polyphenol, nutritional composition (proteins, nitrogen, and minerals), sugars, pyruvate, antioxidant, and α-amylase inhibition activities of red onion cultivars, sweet Italian, and honeysuckle grown in California and Texas, respectively. The total flavonoid for honeysuckle and sweet Italian was 449 and 345 μg/g FW, respectively. The total anthocyanin for honeysuckle onion was 103 μg/g FW, while for sweet Italian onion was 86 μg/g FW. Cyanidin-3-(6”-malonoylglucoside) and cyanidin-3-(6”-malonoyl-laminaribioside) were the major components in both the cultivars. The pungency of red onions in honeysuckle ranged between 4.9 and 7.9 μmoL/mL, whereas in sweet Italian onion ranged from 8.3 to 10 μmoL/mL. The principal component analysis was applied to determine the most important variables that separate the cultivars of red onion. Overall results indicated that total flavonoids, total phenolic content, total anthocyanins, protein, and calories for honeysuckle onions were higher than the sweet Italian onions. These results could provide information about high quality and adding value to functional food due to the phytochemicals and nutritional composition of red onions. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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25 pages, 2989 KiB  
Article
Multivariate Analysis of Amino Acids and Health Beneficial Properties of Cantaloupe Varieties Grown in Six Locations in the United States
by Jashbir Singh, Rita Metrani, Guddadarangavvanahally K. Jayaprakasha, Kevin M. Crosby, Sadhana Ravishankar and Bhimanagouda S. Patil
Plants 2020, 9(9), 1058; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9091058 - 19 Aug 2020
Cited by 12 | Viewed by 3173
Abstract
Cantaloupe is a good dietary source of amino acids, including γ-aminobutyric acid (GABA), glutamine, and citrulline. However, the levels of these amino acids vary among different cantaloupe varieties grown in different locations. Understanding the variation in amino acid contents provides fundamentally important information [...] Read more.
Cantaloupe is a good dietary source of amino acids, including γ-aminobutyric acid (GABA), glutamine, and citrulline. However, the levels of these amino acids vary among different cantaloupe varieties grown in different locations. Understanding the variation in amino acid contents provides fundamentally important information for quality control and improving melon varieties. To examine this variation, we measured the amino acid contents in cantaloupes grown in six locations in the United States (Texas, Georgia, North Carolina, California, Indiana, and Arizona). Principal component analyses were applied to analyze the effect of growing location on the amino acid profiles in different varieties. The GABA content ranged from 1006.14 ± 64.77 to 3187.12 ± 64.96 µg/g and citrulline ranged from 92.65 ± 9.52 to 464.75 ± 34.97 µg/g depending on the variety and location. Total phenolic contents, α-amylase inhibition, and antioxidant activities were also measured. Tuscan type Da Vinci had significantly higher phenolic contents in Arizona (381.99 ± 16.21 µg/g) but had the lowest level when grown in California (224.56 ± 14.62 µg/g). Our analyses showed significant differences in amino acid levels, phenolics contents, and antioxidant activity in the cantaloupe varieties based on the growing location. These findings underline the importance of considering growing location in the selection and improvement of cantaloupe varieties. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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15 pages, 1483 KiB  
Article
Evaluation of Anthocyanin Profile, Antioxidant, Cytoprotective, and Anti-Angiogenic Properties of Callistemon citrinus Flowers
by Giuseppina Laganà, Davide Barreca, Antonella Smeriglio, Maria Paola Germanò, Valeria D'Angelo, Antonella Calderaro, Ersilia Bellocco and Domenico Trombetta
Plants 2020, 9(8), 1045; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9081045 - 17 Aug 2020
Cited by 12 | Viewed by 2653
Abstract
Lemon bottlebrush (Callistemon citrinus (Curtis) Skeels) is one of the most common ornamental plants, diffused worldwide, and characterized by the presence of flowers with an intense red/purple coloration. There is increasing interest in the use and application of anthocyanins for their unique [...] Read more.
Lemon bottlebrush (Callistemon citrinus (Curtis) Skeels) is one of the most common ornamental plants, diffused worldwide, and characterized by the presence of flowers with an intense red/purple coloration. There is increasing interest in the use and application of anthocyanins for their unique structural/chemical features in both food and pharmaceutical applications. RP-HPLC-DAD-ESI-MS/MS analysis of an enriched fraction of acidified methanolic extract of C. citrinus flowers allow the possibility of identifying, for the first time, the presence of four anthocyanins: cyanidin-3,5-O-diglucoside (cyanin), peonidin-3,5-O-diglucoside (peonin), cyanidin-3-O-glucoside, and cyanidin-coumaroylglucoside-pyruvic acid. Moreover, the evaluation of antioxidant and biological potential showed a remarkable activity of this fraction, able to actively scavenge DPPH, AAPH, and ABTS radicals, and to counteract the β-carotene-bleaching. In addition, it protects human mononuclear cells from oxidative injuries and prevents angiogenesis (acting in the range of few μg/ml); furthermore, it does not show significant iron-chelating ability (up to 200 µg/mL). The easy way of cultivation, robustness, and adaptability to different environments make the flowers of this plant a useful source of anthocyanins, with remarkable health promoting properties. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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15 pages, 1251 KiB  
Article
Influence of the Maturity Stage on the Phytochemical Composition and the Antioxidant Activity of Four Andean Blackberry Cultivars (Rubus glaucus Benth) from Ecuador
by Iván Samaniego, Beatriz Brito, William Viera, Ana Cabrera, Wilma Llerena, Tissa Kannangara, Rubén Vilcacundo, Ignacio Angós and Wilman Carrillo
Plants 2020, 9(8), 1027; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9081027 - 13 Aug 2020
Cited by 26 | Viewed by 4345
Abstract
Andean blackberries (Rubus glaucus Benth) are fruits rich in phytocomponents with high antioxidant activity. In this work, the changes in the total polyphenol content (TPC), the total flavonoid content (TFC), and the total anthocyanin content (TAC) of four blackberry varieties at three [...] Read more.
Andean blackberries (Rubus glaucus Benth) are fruits rich in phytocomponents with high antioxidant activity. In this work, the changes in the total polyphenol content (TPC), the total flavonoid content (TFC), and the total anthocyanin content (TAC) of four blackberry varieties at three maturity stages (E1-25%, E2-50%, and E3-100%) were measured. The antioxidant activity (AA) was evaluated using the 2,2’azinobis-(3-ethylbenzthiazolin 6-sulphonic acid (ABTS) and ferric reducing antioxidant power (FRAP) methods. TPC and TFC content decreased with the increase in the maturity stage. The blackberry Brazos cultivar presented TPC values of 51.26, 38.16, and 31.59 mg of gallic acid equivalents (GAE)/g dry weight (DW) at E1, E2, and E3, respectively. The TAC and soluble solids increased with the increase in the maturity stage of the fruits. The Andimora variety at E3 presented a high TPC content, and the Colombiana variety presented a high TFC content. The blackberry Colombiana cultivar presented TAC values of 1.40, 2.95, and 12.26 mg cy-3-glu/100g DW at E1, E2, and E3, respectively. The blackberry Colombiana cultivar presented a high AA value at 1278.63 µmol TE/g DW according to the ABTS method and 1284.55 µmol TE/g DW according to the FRAP method. The TPC and TFC showed a high correlation with the AA according to the ABTS and the FRAP methods. The Pearson correlation between the TFC and AA/ABTS has a value of r = 0.92. The TFC and AA/FRAP present a value of r = 0.94. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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17 pages, 2985 KiB  
Article
Melatonin Suppressed the Heat Stress-Induced Damage in Wheat Seedlings by Modulating the Antioxidant Machinery
by Zeeshan Ali Buttar, Sheng Nan Wu, Marino B. Arnao, Chaojie Wang, Ikram Ullah and Chengshe Wang
Plants 2020, 9(7), 809; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9070809 - 28 Jun 2020
Cited by 96 | Viewed by 5232
Abstract
Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that plays a crucial role in the regulation of various environmental stresses, including heat stress (HS). In this study, a 100 μM melatonin (MT) pretreatment followed by exposure to heat stress for different time [...] Read more.
Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that plays a crucial role in the regulation of various environmental stresses, including heat stress (HS). In this study, a 100 μM melatonin (MT) pretreatment followed by exposure to heat stress for different time periods was found to efficiently reduce oxidative stress by preventing the over-accumulation of hydrogen peroxide (H2O2), lowering the lipid peroxidation content (malondialdehyde (MDA) content), and increasing proline (Pro) biosynthesis. Moreover, the activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), were increased substantially in MT-pretreated wheat seedlings. The presence of MT significantly improved the heat tolerance of wheat seedlings by modulating their antioxidant defense system, activating the ascorbate–glutathione (AsA–GSH) cycle comprising ascorbate peroxidase (APX), and increasing glutathione reductase (GR) activities. It also held the photosynthetic machinery stable by increasing the chlorophyll content. Enhancement in the endogenous MT contents was also observed in the MT+HS-treated plants. Furthermore, the expression of reactive oxygen species (ROS)-related genes TaSOD, TaPOD, and TaCAT, and anti-stress responsive genes, such as TaMYB80, TaWRKY26, and TaWRKY39, was also induced in MT-treated seedlings. Due to these notable changes, an improvement in stress resistance was observed in MT-treated seedlings compared with control. Taken together, our findings suggest that MT can play a key role in boosting the stress tolerance of plants by modulating the antioxidant defense system and regulating the transcription of stress-responsive genes. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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17 pages, 1928 KiB  
Article
Mechanisms Underlying the Anti-Inflammatory Activity of Bergamot Essential Oil and Its Antinociceptive Effects
by Giovanni Enrico Lombardo, Santa Cirmi, Laura Musumeci, Simona Pergolizzi, Alessandro Maugeri, Caterina Russo, Carmen Mannucci, Gioacchino Calapai and Michele Navarra
Plants 2020, 9(6), 704; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9060704 - 01 Jun 2020
Cited by 35 | Viewed by 4165
Abstract
Renewed interest in natural products as potential source of drugs led us to investigate on both the anti-inflammatory and anti-nociceptive activity of Citrus bergamia Risso et Poiteau (bergamot) essential oil (BEO). Carrageenan-induced paw edema in rats was used as an experimental model of [...] Read more.
Renewed interest in natural products as potential source of drugs led us to investigate on both the anti-inflammatory and anti-nociceptive activity of Citrus bergamia Risso et Poiteau (bergamot) essential oil (BEO). Carrageenan-induced paw edema in rats was used as an experimental model of inflammation. Because of the toxicity of furocoumarins, we performed our study by using the BEO fraction deprived of these compounds (BEO-FF). Treatment with BEO-FF led to a significant inhibition of paw edema induced by a sub-plantar injection of carrageenan. Moreover, histological examination of BEO-FF-treated rat paw biopsies showed a reduction of pathological changes typical of edema. Pre-treatment with BEO-FF significantly reduced interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels in the paw homogenates, as well as nitrite/nitrate and prostaglandin E2 (PGE2) content in exudates. In addition, BEO-FF possesses antioxidant properties, as determined by cell-free assays. Furthermore, results of the writhing test showed that BEO-FF elicited a pronounced analgesic response, as demonstrated by a significant inhibition of constrictions in mice receiving acetic acid, with respect to control animals, whereas the results of the hot plate test suggested that the supra-spinal analgesia participates in the anti-nociceptive effect of BEO-FF. Our study indicates that BEO-FF exerts anti-inflammatory and anti-nociceptive effects, and suggests its potential role as an anti-edemigen and analgesic drug. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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9 pages, 412 KiB  
Article
Effects of Monoterpenes of Trachyspermum ammi on the Viability of Spermatogonia Stem Cells In Vitro
by Sahar Omidpanah, Fereshte Aliakbari, Seyed Mohammad Nabavi, Mahdi Vazirian, Abbas Hadjiakhoondi, Mahdieh Kurepaz-mahmoodabadi and Azadeh Manayi
Plants 2020, 9(3), 343; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9030343 - 09 Mar 2020
Cited by 2 | Viewed by 2762
Abstract
Trachyspermum ammi (Apiaceae) plants have several medicinal and condimentary applications and are considered an aphrodisiac agent in Iranian Traditional Medicine. Thus, the present study aims to evaluate the effects of oil from Iranian T. ammi plants on the viability of spermatogonial stem cells [...] Read more.
Trachyspermum ammi (Apiaceae) plants have several medicinal and condimentary applications and are considered an aphrodisiac agent in Iranian Traditional Medicine. Thus, the present study aims to evaluate the effects of oil from Iranian T. ammi plants on the viability of spermatogonial stem cells in vitro. The essential oil of T. ammi fruits was extracted by hydrodistillation, and the amount of thymol was calculated by a gas-chromatography method. Spermatogonial stem cells were isolated from the testes of mice using enzyme digestion. Real-time polymerase chain reaction (RT-PCR) was applied to assess the gene expressions of promyelocytic leukemia zinc finger protein (Plzf), DNA-binding protein inhibitor (ID-4), tyrosine-protein kinase (c-Kit), B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (BAX). The number and diameter of colonies were also measured in the treated cells. The amount of thymol in the oil was 130.7 ± 7.6 µg/mL. Flow cytometry analysis showed that 92.8% of all cells expressed stimulated by retinoic acid 8 (Stra8), a spermatogonial stem cell marker. Expression of Plzf and ID-4 genes significantly increased in the treatment groups, while c-Kit and BAX decreased, and Bcl2 increased in the presence of essential oil. The numbers and diameters of cells were also improved by the application of the plant oil. These data indicated that monoterpenes from the oil of T. ammi improved the quality and viability of spermatogonia cells in the cell culture. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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11 pages, 1852 KiB  
Article
In Vitro Anti-HSV-1 Activity of Polyphenol-Rich Extracts and Pure Polyphenol Compounds Derived from Pistachios Kernels (Pistacia vera L.)
by Maria Musarra-Pizzo, Rosamaria Pennisi, Ichrak Ben-Amor, Antonella Smeriglio, Giuseppina Mandalari and Maria Teresa Sciortino
Plants 2020, 9(2), 267; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9020267 - 18 Feb 2020
Cited by 32 | Viewed by 4999
Abstract
Natural compounds are a prominent source of novel antiviral drugs. Several reports have previously shown the antimicrobial activity of pistachio polyphenol extracts. Therefore, the aim of our research was to investigate the activity of polyphenol-rich extracts of natural shelled (NPRE) pistachios kernels ( [...] Read more.
Natural compounds are a prominent source of novel antiviral drugs. Several reports have previously shown the antimicrobial activity of pistachio polyphenol extracts. Therefore, the aim of our research was to investigate the activity of polyphenol-rich extracts of natural shelled (NPRE) pistachios kernels (Pistacia vera L.) on herpes simplex virus type 1 (HSV-1) replication. The Vero cell line was used to assess the cytotoxicity and antiviral activity. The cell viability was calculated by detection of cellular ATP after treatment with various concentrations of NPRE. For antiviral studies, five nontoxic-concentrations (0.1, 0.2, 0.4, 0.6, 0.8 mg/mL) were tested. Our study demonstrated that treatment with NPRE (0.4, 0.6, 0.8 mg/mL) reduced the expression of the viral proteins ICP8 (infected cell polypeptide 8), UL42 (unique long UL42 DNA polymerase processivity factor), and US11 (unique short US11 protein), and resulted in a decrease of viral DNA synthesis. The 50% cytotoxic concentration (CC50), 50% inhibitory concentration (EC50), and the selectivity index (SI) values for NPRE were 1.2 mg/mL, 0.4mg/mL, and 3, respectively. Furthermore, we assessed the anti-herpetic effect of a mix of pure polyphenol compounds (NS MIX) present in NPRE. In conclusion, our findings indicate that natural shelled pistachio kernels have remarkable inhibitory activity against HSV-1. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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Review

Jump to: Editorial, Research

22 pages, 1219 KiB  
Review
Melatonin: Awakening the Defense Mechanisms during Plant Oxidative Stress
by Adil Khan, Muhammad Numan, Abdul Latif Khan, In-Jung Lee, Muhammad Imran, Sajjad Asaf and Ahmed Al-Harrasi
Plants 2020, 9(4), 407; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9040407 - 25 Mar 2020
Cited by 122 | Viewed by 8397
Abstract
Melatonin is a multifunctional signaling molecule that is ubiquitously distributed in different parts of a plant and responsible for stimulating several physio-chemical responses to adverse environmental conditions. In this review, we show that, although plants are able to biosynthesize melatonin, the exogenous application [...] Read more.
Melatonin is a multifunctional signaling molecule that is ubiquitously distributed in different parts of a plant and responsible for stimulating several physio-chemical responses to adverse environmental conditions. In this review, we show that, although plants are able to biosynthesize melatonin, the exogenous application of melatonin to various crops can improve plant growth and development in response to various abiotic and biotic stresses (e.g., drought, unfavorable temperatures, high salinity, heavy metal contamination, acid rain, and combined stresses) by regulating antioxidant machinery of plants. Current knowledge suggests that exogenously applied melatonin can enhance the stress tolerance of plants by regulating both the enzymatic and non-enzymatic antioxidant defense systems. Enzymic antioxidants upregulated by exogenous melatonin include superoxide dismutase, catalase, glutathione peroxidase, and enzymes involved in the ascorbate–glutathione cycle (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase), whereas levels of non-enzymatic antioxidants such as ascorbate, reduced glutathione, carotenoids, tocopherols, and phenolics are also higher under stress conditions. The enhanced antioxidant system consequently exhibits lower lipid peroxidation and greater plasma membrane integrity when under stress. However, these responses vary greatly from crop to crop and depend on the intensity and type of stress, and most studies to date have been conducted under controlled conditions. This means that a wider range of crop field trials and detailed transcriptomic analysis are required to reveal the gene regulatory networks involved in the between melatonin, antioxidants, and abiotic stress. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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40 pages, 2223 KiB  
Review
Isatis tinctoria L. (Woad): A Review of Its Botany, Ethnobotanical Uses, Phytochemistry, Biological Activities, and Biotechnological Studies
by Jasmine Speranza, Natalizia Miceli, Maria Fernanda Taviano, Salvatore Ragusa, Inga Kwiecień, Agnieszka Szopa and Halina Ekiert
Plants 2020, 9(3), 298; https://0-doi-org.brum.beds.ac.uk/10.3390/plants9030298 - 01 Mar 2020
Cited by 47 | Viewed by 12547
Abstract
Isatis tinctoria L. (Brassicaceae), which is commonly known as woad, is a species with an ancient and well-documented history as an indigo dye and medicinal plant. Currently, I. tinctoria is utilized more often as medicinal remedy and also as a cosmetic ingredient. In [...] Read more.
Isatis tinctoria L. (Brassicaceae), which is commonly known as woad, is a species with an ancient and well-documented history as an indigo dye and medicinal plant. Currently, I. tinctoria is utilized more often as medicinal remedy and also as a cosmetic ingredient. In 2011, I. tinctoria root was accepted in the official European phytotherapy by introducing its monograph in the European Pharmacopoeia. The biological properties of raw material have been known from Traditional Chinese Medicine (TCM). Over recent decades, I. tinctoria has been investigated both from a phytochemical and a biological point of view. The modern in vitro and in vivo scientific studies proved anti-inflammatory, anti-tumour, antimicrobial, antiviral, analgesic, and antioxidant activities. The phytochemical composition of I. tinctoria has been thoroughly investigated and the plant was proven to contain many valuable biologically active compounds, including several alkaloids, among which tryptanthrin, indirubin, indolinone, phenolic compounds, and polysaccharides as well as glucosinolates, carotenoids, volatile constituents, and fatty acids. This article provides a general botanical and ethnobotanical overview that summarizes the up-to-date knowledge on the phytochemistry and biological properties of this valuable plant in order to support its therapeutic potential. Moreover, the biotechnological studies on I. tinctoria, which mainly focused on hairy root cultures for the enhanced production of flavonoids and alkaloids as well as on the establishment of shoot cultures and micropropagation protocols, were reviewed. They provide input for future research prospects. Full article
(This article belongs to the Special Issue Mechanisms of Plant Antioxidants Action)
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