Foliar treatment with MSB (menadione sodium bisulphite) to increase artemisinin content in Artemisia annua plants

Artemisinin is a sesquiterpene lactone endoperoxide, recognized for its application as a treatment for malaria. Besides, it has activity against several types of cancers, as well as anti-viral and anti-inflammatory properties. The chemical synthesis of artemisinin is quite complex and economically unfeasible. Hence, artemisinin is typically obtained from Artemisia annua plants in low quantities in relation to the biomass. A strategy to increase the biosynthesis of secondary metabolites would be the application of elicitors. In this work, the effect of treating A. annua plants with menadione sodium bisulphite (MSB) is studied. An initial dose-optimization was conducted by treating the plants with different MBS concentrations (0, 0.2, 0.8, 1, 2, 3 and 4 mM) and artemisinin was quantified 48 h after treatment. The highest artemisinin content (3.71 mg artemisinin g−1 DW) was obtained with 1 mM of MSB. Then, harvesting time was optimised (24, 48 and 72 h after treatment application) with 1 mM of MSB. The largest increase in artemisinin content was observed at 48 h with an increment of 62.37 % over the control. The treatment increased H2O2 content, as well as the activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX). Besides, MSB up-regulated HMGR (the gene for 3-hydroxy-3-methylglutaryl-CoA reductase) and DXS (the gene for 1-deoxy-D-xylulose-5-phosphate synthase) 24 h after treatment. Both genes are involved in the MVA (mevalonate) and MEP (2C-methylerythritol 4-phosphate) pathways, respectively. These pathways represent the initiation of artemisinin biosynthesis. Thus, MSB application and the consequent up-regulation of early biosynthetic pathway genes along with the triggered oxidative stress may have been contributed to the observed increase in artemisinin production.

García-García, Ana L.; Rodríguez-Ramos, Ruth; Borges, Andrés A.; Boto, Alicia; Jiménez-Arias, David.

Scientia Horticulturae, 328, 112913: 1-8 (2024)
DOIDigital.CSIC

Chemical Insights into Oxidative and Nitrative Modifications of DNA

This review focuses on DNA damage caused by a variety of oxidizing, alkylating, and nitrating species, and it may play an important role in the pathophysiology of inflammation, cancer, and degenerative diseases. Infection and chronic inflammation have been recognized as important factors in carcinogenesis. Under inflammatory conditions, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from inflammatory and epithelial cells, and result in the formation of oxidative and nitrative DNA lesions, such as 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and 8-nitroguanine. Cellular DNA is continuously exposed to a very high level of genotoxic stress caused by physical, chemical, and biological agents, with an estimated 10,000 modifications occurring every hour in the genetic material of each of our cells. This review highlights recent developments in the chemical biology and toxicology of 2′-deoxyribose oxidation products in DNA.

Curieses Andrés, Celia María; Lastra, José M. P. de la; Juan, Celia Andrés; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo.

International Journal of Molecular Sciences 24(20), 15240: 1-43 (2023)
DOIDigital.CSIC

Chemistry of Hydrogen Sulfide—Pathological and Physiological Functions in Mammalian Cells

Hydrogen sulfide (H2S) was recognized as a gaseous signaling molecule, similar to nitric oxide (-NO) and carbon monoxide (CO). The aim of this review is to provide an overview of the formation of hydrogen sulfide (H2S) in the human body. H2S is synthesized by enzymatic processes involving cysteine and several enzymes, including cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), cysteine aminotransferase (CAT), 3-mercaptopyruvate sulfurtransferase (3MST) and D-amino acid oxidase (DAO). The physiological and pathological effects of hydrogen sulfide (H2S) on various systems in the human body have led to extensive research efforts to develop appropriate methods to deliver H2S under conditions that mimic physiological settings and respond to various stimuli. These functions span a wide spectrum, ranging from effects on the endocrine system and cellular lifespan to protection of liver and kidney function. The exact physiological and hazardous thresholds of hydrogen sulfide (H2S) in the human body are currently not well understood and need to be researched in depth. This article provides an overview of the physiological significance of H2S in the human body. It highlights the various sources of H2S production in different situations and examines existing techniques for detecting this gas.

Curieses Andrés, Celia María; Pérez de Lastra, José Manuel; Andrés Juan, Celia; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo.

Cells, 12(23), 2684: 1-45 (2023)
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Optimization and bio-fabrication of phyto-mediated silver nanoparticles (Ag-NPs) for antibacterial potential

This report examines the bio-fabrication of silver nanoparticles (Ag-NPs) utilizing AgNO3 and leaf extract of Crataegus monogyna as the precursor material. In order to maximize the antibacterial efficacy against Staphylococcus aureus, Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa, the reaction conditions for the green fabrication of Ag-NPs were optimized. A one factor at a time approach (volume concentration of extract, volume concentration of AgNO3, pH and temperature) was used to optimize the best condition, and results were assessed through UV-visible spectroscopy and particle size distribution. The results showed that 20 mL of plant extract, 80 mL of AgNO3, pH 08, 100 °C temperature were the optimum reaction conditions under which we obtained the smallest Ag-NPs (7 nm). The scanning electron microscopy and X-ray diffraction analysis confirmed the spherical and crystalline nature of Ag-NPs. The antibacterial activity assay demonstrated a high antibacterial effect of Ag-NPs against S. aureus, P. mirabilis, K. pneumoniae and P. aeruginosa, and that impact was greater with smaller-sized nanoparticles (7 nm). This study shows that leaf extract of C. monogyna is a possible medium for the green fabrication of Ag-NPs, and control over reaction factors can establish the characteristics and antibacterial effectiveness of Ag-NPs.

Mehmood, Ansar; Zahir, Sobia; Khan, Muhammad Abdul Rauf; Ahmad, Khawaja Shafique; Abasi, Fozia; Raffi, Muhammad; Proćków, Jarosław; Pérez de Lastra, José Manuel.

Journal of Biomolecular Structure and Dynamics: 1-11 (2023)
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Polyphenols as Antioxidant/Pro-Oxidant Compounds and Donors of Reducing Species: Relationship with Human Antioxidant Metabolism

In this review, we have focused mainly on the study of their antioxidant and pro-oxidant capacity, and the analysis of the oxidation of the catechol group to o-quinone. The redox balance established between the different oxidase and reductase enzymes generates reducing species, H+ and e−, and allows the oxidation of polyphenolic groups to quinones to be reversible. This continuous balance between these nucleophilic and electrophilic substances allows the activation of the NRF2/ARE axis, which regulates cellular antioxidant responses against oxidative stress, as well as cell proliferation. Understanding the ambivalent character of polyphenols, which can act simultaneously as antioxidants and pro-oxidants, will allow the design of specific therapies that can serve science and medicine in their tasks.

Curieses Andrés, Celia María; Pérez de Lastra, José Manuel; Andrés Juan, Celia; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo.

Processes 11(9), 2771: 1-23 (2023)
DOIDigital.CSIC

Biostimulant activity of Galaxaura rugosa seaweed extracts against water deficit stress in tomato seedlings involves activation of ABA signaling

Water scarcity is a serious constraint for agriculture, and global warming and climate change can exacerbate it in many areas. Therefore, sustainable approaches must be implemented to deal with current and future water scarcity scenarios. Genetic and chemical approaches are being applied to manage this limitation and maintain crop yields. In particular, biostimulants obtained from natural sources such as marine algae are promising aids for coping with water deficit stress in agriculture. Here we present a bioprospection study of extracts of the macroalgae Bonnemaisonia hamifera, Galaxaura rugosa, Dasycladus vermicularis, Ulva clathrata, Cystoseira foeniculacea, Cystoseira humilis, Lobophora dagamae, Colpomenia sinuosa and Halopteris scoparia from the north coast of Tenerife, in the Canary Islands. The aqueous extracts of Bonnemaisonia hamifera, Galaxaura rugosa, Dasycladus vermicularis and Cystoseira humilis show biostimulant activity against water deficit stress in tomato seedlings under controlled conditions, providing higher tolerance than the mock-treated control. The Galaxaura rugosa extract showed the highest biostimulant activity against water deficit stress. We demonstrate that this positive effect involves the activation of the abscisic acid (ABA) pathway in Arabidopsis thaliana (arabidopsis) and Solanum lycopersicum (tomato). Application of G. rugosa extract to the root system by drenching tomato seedlings subjected to water deficit leads to improved CO2 assimilation and water use efficiency (WUEp), compared to mock-treated plants. These results highlight a new potential seaweed source of substances with osmoprotectant properties, useful for biostimulant development. Future studies may provide further insight into which components of the seaweed extract induce activation of the ABA pathway.

Morales-Sierra, Sarai; Cristo Luis, Juan; Jiménez-Arias, David; Rancel-Rodríguez, Nereida M.; Coego, Alberto; Rodriguez, Pedro L.; Cueto, Mercedes; Borges, Andrés A.

Frontiers in Plant Science, 14: 1-13 (2023)
DOIDigital.CSIC

Effect of biofertilizers and rhizospheric bacteria on growth and root ultrastucture of lettuce

Biofertilization is a technique that uses plant and animal wastes to add organic matter and nutrients to the soil. It can also use microorganisms that can metabolize these by-products to facilitate their absorption by the plant roots. In this study, we tested the effects of rhizospheric bacteria inoculation (T1), a combination of rhizospheric bacteria with liquid fertilizer (T2) and uncombined liquid fertilizer (T3), on the growth, nutritional content, root tissue, and root cells of lettuce plants. The results showed significant positive differences in all treatments compared to control plants, in terms of morphological, nutritional, and productivity parameters. The combination of rhizospheric bacteria with liquid SEFEL fertilizer (T2) yielded the best results, showing increased fresh and dry weight, and diameter. There were no differences between treatments for nutritional content, but each treatment outperformed the control by more than 700% for all macronutrients. The best result was phosphorus content for T1, with 1272.22% more than control. Regarding root structure and ultrastructure, there was no variation in tissue organization compared to control plants, but increases in root hairs (T1), development of transfer cells (T2), and secondary growth (T3) were observed. Additionally, colonization of roots by rhizospheric bacteria was confirmed in all three treatments. In conclusion, this study suggests that inoculating with rhizospheric bacteria is a viable and environmentally friendly biofertilization for lettuce plants.

Montesdeoca-Flores, David; Alfayate-Casañas, Carmen; Hernández-Bolaños, Eduardo; Hernández-González, Mercedes; Estupiñan-Afonso, Zuleima; Abreu-Acosta, Néstor.

Horticulture, Environment, and Biotechnology: 1-14 (2023)
DOIDigital.CSIC

From reactive species to disease development: Effect of oxidants and antioxidants on the cellular biomarkers

The influence of modern lifestyle, diet, exposure to chemicals such as phytosanitary substances, together with sedentary lifestyles and lack of exercise play an important role in inducing reactive stress (RS) and disease. The imbalance in the production and scavenging of free radicals and the induction of RS (oxidative, nitrosative, and halogenative) plays an essential role in the etiology of various chronic pathologies, such as cardiovascular diseases, diabetes, neurodegenerative diseases, and cancer. The implication of free radicals and reactive species injury in metabolic disturbances and the onset of many diseases have been accumulating for several decades, and are now accepted as a major cause of many chronic diseases. Exposure to elevated levels of free radicals can cause molecular structural impact on proteins, lipids, and DNA, as well as functional alteration of enzyme homeostasis, leading to aberrations in gene expression. Endogenous depletion of antioxidant enzymes can be mitigated using exogenous antioxidants. The current interest in the use of exogenous antioxidants as adjunctive agents for the treatment of human diseases allows a better understanding of these diseases, facilitating the development of new therapeutic agents with antioxidant activity to improve the treatment of various diseases. Here we examine the role that RS play in the initiation of disease and in the reactivity of free radicals and RS in organic and inorganic cellular components.

Curieses Andrés, Celia María; Pérez de Lastra, José Manuel; Andrés Juan, Celia; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo.

Journal of Biochemical and Molecular Toxicology, 37(11): 1-17 (2023)
DOIDigital.CSIC

Abscisic acid mimic-fluorine derivative 4 alleviates water deficit stress by regulating ABA-responsive genes, proline accumulation, CO2 assimilation, water use efficiency and better nutrient uptake in tomato plants

Water deficit represents a serious limitation for agriculture and both genetic and chemical approaches are being used to cope with this stress and maintain plant yield. Next-generation agrochemicals that control stomatal aperture are promising for controlling water use efficiency. For example, chemical control of abscisic acid (ABA) signaling through ABA-receptor agonists is a powerful method to activate plant adaptation to water deficit. Such agonists are molecules able to bind and activate ABA receptors and, although their development has experienced significant advances in the last decade, few translational studies have been performed in crops. Here, we describe protection by the ABA mimic-fluorine derivative 4 (AMF4) agonist of the vegetative growth in tomato plants subjected to water restriction. Photosynthesis in mock-treated plants is markedly impaired under water deficit conditions, whereas AMF4 treatment notably improves CO2 assimilation, the relative plant water content and growth. As expected for an antitranspirant molecule, AMF4 treatment diminishes stomatal conductance and transpiration in the first phase of the experiment; however, when photosynthesis declines in mock-treated plants as stress persists, higher photosynthetic and transpiration parameters are recorded in agonist-treated plants. Additionally, AMF4 increases proline levels over those achieved in mock-treated plants in response to water deficit. Thus water deficit and AMF4 cooperate to upregulate P5CS1 through both ABA-independent and ABA-dependent pathways, and therefore, higher proline levels are produced Finally, analysis of macronutrients reveals higher levels of Ca, K and Mg in AMF4- compared to mock-treated plants subjected to water deficit. Overall, these physiological analyses reveal a protective effect of AMF4 over photosynthesis under water deficit and enhanced water use efficiency after agonist treatment. In summary, AMF4 treatment is a promising approach for farmers to protect the vegetative growth of tomatoes under water deficit stress.

Jiménez-Arias, David; Morales-Sierra, Sarai; Suárez, Emma; Lozano-Juste, Jorge; Coego, Alberto; Estevez, Juan C.; Borges, Andrés A. ; Rodriguez, Pedro L.

Frontiers in Plant Science 14, 1191967: 1-12 (2023)
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Hydroxytyrosol and Arginine as Antioxidant, Anti-Inflammatory and Immunostimulant Dietary Supplements for COVID-19 and Long COVID

Phytochemicals from plant extracts are becoming increasingly popular in the world of food science and technology because they have positive effects on human health. In particular, several bioactive foods and dietary supplements are being investigated as potential treatments for chronic COVID. Hydroxytyrosol (HXT) is a natural antioxidant, found in olive oil, with antioxidant anti-inflammatory properties that has been consumed by humans for centuries without reported adverse effects. Its use was approved by the European Food Safety Authority as a protective agent for the cardiovascular system. Similarly, arginine is a natural amino acid with anti-inflammatory properties that can modulate the activity of immune cells, reducing the production of pro-inflammatory cytokines such as IL-6 and TNF-α. The properties of both substances may be particularly beneficial in the context of COVID-19 and long COVID, which are characterised by inflammation and oxidative stress. While l-arginine promotes the formation of •NO, HXT prevents oxidative stress and inflammation in infected cells. This combination could prevent the formation of harmful peroxynitrite, a potent pro-inflammatory substance implicated in pneumonia and COVID-19-associated organ dysfunction, as well as reduce inflammation, improve immune function, protect against free radical damage and prevent blood vessel injury. Further research is needed to fully understand the potential benefits of HXT and arginine in the context of COVID-19.

Pérez de Lastra, José Manuel; Curieses Andrés, Celia María; Andrés Juan, Celia; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo.

Foods 12(10), 1937: 1-15 (2023)
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