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Keywords = Fe2+-chelating

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20 pages, 4386 KiB  
Article
Foliar Application of Salicylic Acid Stimulates Phenolic Compound Accumulation and Antioxidant Potential in Saposhnikovia divaricata Herb
by Daniil N. Olennikov, Nina I. Kashchenko and Nadezhda K. Chirikova
Horticulturae 2025, 11(8), 895; https://doi.org/10.3390/horticulturae11080895 (registering DOI) - 2 Aug 2025
Abstract
Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk., commonly known as divaricate siler, is a well-known medicinal plant from the Apiaceae family. Its natural habitat is rapidly declining owing to the harvesting of its roots, used as fángfēng in traditional Oriental medicine. This underutilized herb [...] Read more.
Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk., commonly known as divaricate siler, is a well-known medicinal plant from the Apiaceae family. Its natural habitat is rapidly declining owing to the harvesting of its roots, used as fángfēng in traditional Oriental medicine. This underutilized herb may serve as a valuable source of bioactive phenolic compounds, which can potentially be influenced by salicylic acid (SA) elicitation—a practical method to increase the concentration of valuable substances in plants. A field study showed that foliar application of SA on one-year-old S. divaricata positively influenced the total phenolic content in the herb, with the highest increase observed at 1.0 mM SA. Liquid chromatography–mass spectrometry (LC–MS) data became increasingly complex with rising SA levels, identifying up to 48 compounds, including cinnamoyl quinic acids (CQAs), dihydrofurochromones (DFCs), and flavonol O-glycosides (FOGs), most reported for the first time in this species. The highest concentrations of CQAs, DFCs, and FOGs in plants treated with 1.0 mM SA were 83.14, 3.75, and 60.53 mg/g, respectively, compared to 42.76, 0.95, and 40.73 mg/g in untreated (0.0 mM SA) plants. Nine in vitro antioxidant assays revealed strong radical-scavenging and nitric oxide (NO)- and Fe2+-chelating activities in 1.0 mM SA-treated plants, indicating robust antioxidative properties of the S. divaricata herb. Thus, foliar application of SA considerably enriches the herb with target antioxidants, increasing its medicinal value, which is reflected in the plant’s biological response. This could potentially reduce the overexploitation of natural populations of S. divaricata, helping to preserve this valuable plant. Full article
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15 pages, 2406 KiB  
Article
Adsorption Performance and Mechanism of Gallium from Sulfuric Acid Leach Liquor of High-Alumina Fly Ash
by Wenfen Wu, Chaolu Wen, Shaopeng Li, Zhenhua Sun, Xinjuan Hou, Huiquan Li and Zhibin Ma
Separations 2025, 12(8), 190; https://doi.org/10.3390/separations12080190 - 23 Jul 2025
Viewed by 188
Abstract
High-alumina fly ash may potentially be a valuable source of Ga with a concentration of Ga at 80 mg/kg. Direct adsorption and enrichment of Ga from sulfuric acid leach liquor of high-alumina fly ash is developed in this study. The H-type chelating resin [...] Read more.
High-alumina fly ash may potentially be a valuable source of Ga with a concentration of Ga at 80 mg/kg. Direct adsorption and enrichment of Ga from sulfuric acid leach liquor of high-alumina fly ash is developed in this study. The H-type chelating resin with two carboxy groups exhibited the best adsorption capacity for Ga. The maximum adsorption capacity for Ga was 55 mg/g resin with an adsorption time of 24 h, an initial Ga concentration of 500 mg/L, an adsorption temperature of 55 °C, and an initial acid concentration of 0.1 mol/L. The adsorption process of Ga was in good fit with the Langmuir isotherm and pseudo-second-order reaction kinetics model. The chemical adsorption rate was controlled by an internal diffusion mechanism. The resin had a high selectivity for Ga3+ with a Kd over 3600 compared with Fe2+, Al3+, K+, Ca2+, and Mg2+. The adsorption mechanism was found to be the ion exchange reaction between Ga and H of carboxy and hydroxyl groups. The concentration of Ga in sulfuric acid leach liquor from high-alumina fly ash achieved enrichment from 200 mg/L to 2 g/L. It is an attractive medium for large-scale Ga extraction from high-alumina fly ash. Full article
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20 pages, 2415 KiB  
Article
Intercropping with Gramineous Plants in Nutrient Solutions as a Tool to Optimize the Use of Iron in Brassica oleracea
by Teresa Saavedra, Maribela Pestana, João Costa, Paula Gonçalves, David Fangueiro, José Paulo Da Silva and Pedro José Correia
Plants 2025, 14(14), 2215; https://doi.org/10.3390/plants14142215 - 17 Jul 2025
Viewed by 282
Abstract
This study aimed to evaluate the impact of intercropping Brassica oleracea. with three perennial grasses (Poa pratensis L., Lolium perenne L., and Festuca rubra L.) under varying levels of iron (Fe) availability (Fe0, Fe1 and Fe5) in nutrient solutions. The research [...] Read more.
This study aimed to evaluate the impact of intercropping Brassica oleracea. with three perennial grasses (Poa pratensis L., Lolium perenne L., and Festuca rubra L.) under varying levels of iron (Fe) availability (Fe0, Fe1 and Fe5) in nutrient solutions. The research focused on biomass accumulation, photosynthetic efficiency, root development, nutrient uptake, and oxidative stress response. In the absence of Fe, Brassica sp. exhibited chlorosis, reduced biomass, and increased ferric chelate reductase (FCR) enzyme activity as an adaptive response. Brassica plants intercropped with Poa sp. maintained higher chlorophyll (Chl) levels and photosystem II efficiency (Fv/Fm values), mitigating Fe deficiency effects. Catalase activity and polyphenol production varied with intercropping species, indicating differential stress response mechanisms. Intercropping improved Zn, Mn, and P accumulation, with Poa sp. facilitating greater Zn and Mn uptake. Intercropping Brassica sp. with specific grass species offers potential agronomic benefits by improving Fe use efficiency, mitigating stress, and enhancing nutrient uptake. Future research should focus on optimizing intercropping combinations for sustainable agricultural practices. Full article
(This article belongs to the Section Plant Nutrition)
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19 pages, 3216 KiB  
Article
The Mechanism of an Fe-Based MOF Material as a Foliar Inhibitor and Its Co-Mitigation Effects on Arsenic and Cadmium Accumulation in Rice Grains
by Tianyu Wang, Hao Cui, Weijie Li, Zhenmao Jiang, Lei Li, Lidan Lei and Shiqiang Wei
Agronomy 2025, 15(7), 1710; https://doi.org/10.3390/agronomy15071710 - 16 Jul 2025
Viewed by 313
Abstract
Arsenic (As) and cadmium (Cd) in rice grains are major global food safety concerns. Iron (Fe) can help reduce both, but current Fe treatments suffer from poor stability, low leaf absorption, and fast soil immobilization, with unclear underlying mechanisms. To address these issues, [...] Read more.
Arsenic (As) and cadmium (Cd) in rice grains are major global food safety concerns. Iron (Fe) can help reduce both, but current Fe treatments suffer from poor stability, low leaf absorption, and fast soil immobilization, with unclear underlying mechanisms. To address these issues, an Fe-based metal–organic framework (MIL-88) was modified with sodium alginate (SA) to form MIL-88@SA. Its stability as a foliar inhibitor and its leaf absorption were tested, and its effects on As and Cd accumulation in rice were compared with those of soluble Fe (FeCl3) and chelating Fe (HA + FeCl3) in a field study on As–Cd co-contaminated rice paddies. Compared with the control, MIL-88@SA outperformed or matched the other Fe treatments. A single foliar spray during the tillering stage increased the rice yield by 19% and reduced the inorganic As and Cd content in the grains by 22.8% and 67.8%, respectively, while the other Fe treatments required two sprays. Its superior performance was attributed to better leaf affinity and thermal stability. Laser ablation inductively coupled plasma–mass spectrometry (LA–ICP–MS) and confocal laser scanning microscopy (CLSM) analyses revealed that Fe improved photosynthesis and alleviated As–Cd stress in leaves, MIL-88@SA promoted As and Cd redistribution, and Fe–Cd co-accumulation in leaf veins enhanced Cd retention in leaves. Full article
(This article belongs to the Topic Effect of Heavy Metals on Plants, 2nd Volume)
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17 pages, 3709 KiB  
Article
In Situ Gel-Forming System for the Removal of Ferruginous Deposits on Nanhai I Shipwreck
by Jianrui Zha, Ruyi Wang, Jing Du, Naisheng Li and Xiangna Han
Gels 2025, 11(7), 543; https://doi.org/10.3390/gels11070543 - 12 Jul 2025
Viewed by 236
Abstract
The removal of iron deposits on shipwreck surfaces by mechanical cleaning is labour-intensive work. This study develops an in situ gel and peeling cleaning method, utilising a carboxymethyl chitosan/tannic acid (CMCS/TA) colloidal solution spray on the surface of ferruginous deposits, promoting their removal [...] Read more.
The removal of iron deposits on shipwreck surfaces by mechanical cleaning is labour-intensive work. This study develops an in situ gel and peeling cleaning method, utilising a carboxymethyl chitosan/tannic acid (CMCS/TA) colloidal solution spray on the surface of ferruginous deposits, promoting their removal by adhesion, chelation, and electrostatic bonding processes. The investigation confirmed that the CMTA-2 sample exhibited a sprayable viscosity of 263 mPa/s, the largest single removal thickness of 1.01 mm, a significant reduction in the fe/s atomic ratio by 2.53 units, and enhanced the deposit removal homogeneity. The field testing of the Nanhai I cultural relic showed a 14.37% reduction in iron concentration and a significant decrease in red colour (Δa* = 4.36). The synergistic mechanism involves TA chelating Fe2+/Fe3+ ions, while the CMCS gel network facilitates interfacial adhesion and mechanical peeling, hence promoting efficient and controllable cleaning. Full article
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15 pages, 966 KiB  
Article
Isolation of a Novel Bioactive Fraction from Saffron (Crocus sativus L.) Leaf Waste: Optimized Extraction and Evaluation of Its Promising Antiproliferative and Chemoprotective Effects as a Plant-Based Antitumor Agent
by Raúl Sánchez-Vioque, Julio Girón-Calle, Manuel Alaiz, Javier Vioque-Peña, Adela Mena-Morales, Esteban García-Romero, Lourdes Marchante-Cuevas and Gonzalo Ortiz de Elguea-Culebras
Appl. Sci. 2025, 15(13), 7376; https://doi.org/10.3390/app15137376 - 30 Jun 2025
Viewed by 293
Abstract
Saffron spice is obtained from the flower’s stigmas through a labor-intensive process. However, other organs (particularly the leaves and tepals) are often regarded as waste. To investigate the health benefits of saffron leaf by-products, an optimized methodology was developed to obtain a phenol-enriched [...] Read more.
Saffron spice is obtained from the flower’s stigmas through a labor-intensive process. However, other organs (particularly the leaves and tepals) are often regarded as waste. To investigate the health benefits of saffron leaf by-products, an optimized methodology was developed to obtain a phenol-enriched fraction. The main components of this fraction were identified by HPLC-DAD/ESI-MS and the antiproliferative and metal-chelating effects on colon cancer cells (Caco-2) and Fe2+ and Cu2+ ions, respectively, were evaluated. The process involved the extraction of saffron leaves with a 70% hydroalcoholic solution, followed by purification using liquid chromatography. Chemical characterization revealed the presence of several phenolic compounds, including flavonoids (kaempferol, luteolin and quercetin glycosides) as major constituents; whereas, in vitro assays revealed a strong dose-dependent inhibition of cell proliferation. Likewise, the sample exhibited significant iron- and copper-chelating activity, suggesting its potential as a natural chelator to help mitigate the carcinogenic effects of metal accumulation in humans. In summary, this study underscores the potential of the saffron leaf fraction as a promising natural and complementary chemoprotective agent in colorectal cancer. Additionally, these results underscore the value of agricultural by-products, supporting a circular bioeconomy by reducing environmental impact and promoting the sustainable use of natural resources. Full article
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17 pages, 3841 KiB  
Article
Preparation of Magnetic Carbon Composite from Waste Amine-Oxime Resin and Its Adsorption Properties for Chromium
by Haoyu Wang, Xianzhuo Su, Hongdan Yu, Yuhang Yuan, Jing Wu, Wenchao Yang and Chunlin He
Materials 2025, 18(13), 3066; https://doi.org/10.3390/ma18133066 - 27 Jun 2025
Viewed by 292
Abstract
A waste amidoxime chelate resin (WAR) was converted into a magnetic composite adsorbent (MCA) via carbonization and magnetization for the effective removal of Cr(VI). Under optimized conditions (pH = 1, 30 °C, 1 h), the adsorbent achieved a maximum Cr(VI) adsorption capacity of [...] Read more.
A waste amidoxime chelate resin (WAR) was converted into a magnetic composite adsorbent (MCA) via carbonization and magnetization for the effective removal of Cr(VI). Under optimized conditions (pH = 1, 30 °C, 1 h), the adsorbent achieved a maximum Cr(VI) adsorption capacity of 197.63 mg/g. The adsorption process conformed to the pseudo-second-order kinetic model (R2 > 0.98) and Langmuir isotherm model (R2 > 0.99). The materials can be separated by magnetism. The primary mechanism for the adsorption of Cr(VI) involved monolayer chemisorption. FTIR spectroscopy confirmed the dominant role of -C=O, C-O, and Fe-O in the adsorption process. XPS spectroscopy confirmed the dominant role of -C=O and C-O in the adsorption process. The successful conversion of the WAR into an MCA not only mitigates waste accumulation but also provides a cost-effective strategy for heavy metal remediation. Full article
(This article belongs to the Special Issue Adsorption Materials and Their Applications (2nd Edition))
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21 pages, 4500 KiB  
Article
Vvmrp1, Vvmt1, and Vvmt2 Co-Expression Improves Cadmium Tolerance and Reduces Cadmium Accumulation in Rice
by Hongjuan Han, Yu Wang, Cen Qian, Quanhong Yao and Qiaoquan Liu
Agronomy 2025, 15(6), 1493; https://doi.org/10.3390/agronomy15061493 - 19 Jun 2025
Viewed by 339
Abstract
Cadmium (Cd) contamination in agricultural soils severely threatens rice production and food safety. To address this issue, this study developed transgenic rice lines co-expressing three Vitis vinifera genes: the ABCC transporter Vvmrp1 and metallothioneins Vvmt1 and Vvmt2. AlphaFold computational modeling confirmed the [...] Read more.
Cadmium (Cd) contamination in agricultural soils severely threatens rice production and food safety. To address this issue, this study developed transgenic rice lines co-expressing three Vitis vinifera genes: the ABCC transporter Vvmrp1 and metallothioneins Vvmt1 and Vvmt2. AlphaFold computational modeling confirmed the conserved ABCC-type transporter domain in VvMRP1. Under hydroponic conditions, transgenic rice showed remarkable Cd tolerance, surviving 30 mM Cd (lethal to wildtype, WT) without growth penalties, and exhibited 62.5% survival at 1 mM Cd vs. complete wild-type mortality. Field-relevant Cd exposure (1 mM) reduced Cd accumulation to 35.8% in roots, 83% in stems, and 76.8% in grains compared to WT. Mechanistic analyses revealed that Vvmrp1 mediates cellular Cd efflux while Vvmt1 and 2 chelate free Cd ions, synergistically inhibiting Cd translocation. Transgenic plants also maintained better Fe, P, and Mg homeostasis under Cd stress. This study pioneers the co-expression of a transporter with metallothioneins in rice, demonstrating their complementary roles in Cd detoxification without pleiotropic effects from endogenous gene modification. The findings provide an effective genetic strategy for cultivating low-Cd rice in contaminated soils, offering significant implications for food safety and sustainable agriculture. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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22 pages, 815 KiB  
Article
Effect of Nutrient Forms in Foliar Fertilizers on the Growth and Biofortification of Maize on Different Soil Types
by Rafał Januszkiewicz, Grzegorz Kulczycki, Elżbieta Sacała and Cezary Kabała
Agronomy 2025, 15(6), 1482; https://doi.org/10.3390/agronomy15061482 - 18 Jun 2025
Cited by 1 | Viewed by 654
Abstract
This research aimed to evaluate how different chemical forms of key nutrients, delivered through an advanced foliar product (PRO) and a standard formulation (TRA), influence maize performance when grown on contrasting soil types. Each fertilizer provided a set of macro- and micronutrients, including [...] Read more.
This research aimed to evaluate how different chemical forms of key nutrients, delivered through an advanced foliar product (PRO) and a standard formulation (TRA), influence maize performance when grown on contrasting soil types. Each fertilizer provided a set of macro- and micronutrients, including nitrogen, phosphorus, potassium, boron, copper, iron, manganese, molybdenum, and zinc, along with trace elements such as chromium, iodine, lithium, and selenium. In TRA, Fe and Zn were complexed with EDTA, and trace elements were present in mineral form. In PRO, Fe and Zn were chelated with amino acids, and trace elements were bound to plant extracts. The study examined increasing doses of PRO and their potential toxicity. Both fertilizers improved maize biomass: fresh weight increased by 5–8% and dry weight by 8–14%, depending on the dose. At the lowest dose, yields were similar. However, PRO was more effective in biofortifying maize with iron and zinc on sandy soil, increasing levels by 16% and 7% compared to TRA at the lowest dose and up to 29% at the highest dose. PRO was well tolerated at higher doses. No significant differences were observed between the second and third doses of PRO, suggesting reduced efficacy at the highest dose. Full article
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22 pages, 4202 KiB  
Article
Donkey-Hide Gelatin Peptide-Iron Complexes: Structural Characterization, Enhanced Iron Solubility Under Simulated Digestion, and Dual Iron Chelation-Antioxidant Functions
by Lili Yang, Chenyan Lv, Xingfeng Guo and Rong Liang
Foods 2025, 14(12), 2117; https://doi.org/10.3390/foods14122117 - 17 Jun 2025
Viewed by 573
Abstract
Iron deficiency is a global health issue, making the development of novel iron supplements to enhance iron absorption critically important. In this study, low molecular weight donkey-hide gelatin peptides (LMW DHGP) were enzymatically hydrolyzed from donkey-hide gelatin. Experimental results demonstrated that the iron [...] Read more.
Iron deficiency is a global health issue, making the development of novel iron supplements to enhance iron absorption critically important. In this study, low molecular weight donkey-hide gelatin peptides (LMW DHGP) were enzymatically hydrolyzed from donkey-hide gelatin. Experimental results demonstrated that the iron chelating capacity of LMW DHGP reached 249.98 μg/mg. Key amino acids (Asn, Gly, Cys, Lys) may participate in chelation. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis showed rough, porous amorphous structures of LMW DHGP-iron complexes. The results of circular dichroism spectroscopy (CD) indicated that the self-assembly of LMW DHGP-iron complexes appears to be primarily mediated by peptide α-helical structural conformations. Fourier transform infrared (FTIR) spectroscopy further indicated that the interaction between LWM DHGP and Fe2+ likely occurs through carboxyl and amino functional groups. In vitro digestion stability studies demonstrated that LMW DHGP-iron complexes exhibited superior iron ion solubility compared to FeSO4 in simulated gastrointestinal conditions. PGPAG-iron complexes exhibited the highest antioxidant activity, with scavenging rates of 71.64% (DPPH radical) and 88.79% (ABTS radical). These findings collectively suggest that LMW DHGP-iron complexes possess significant potential as a novel iron supplement in food applications, which provides valuable theoretical insights for the development of innovative iron supplementation strategies. Full article
(This article belongs to the Special Issue Bioactive Peptides and Probiotic Bacteria: Modulators of Human Health)
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28 pages, 5779 KiB  
Article
Theoretical Insight into Antioxidant Mechanisms of Trans-Isoferulic Acid in Aqueous Medium at Different pH
by Agnieszka Kowalska-Baron
Int. J. Mol. Sci. 2025, 26(12), 5615; https://doi.org/10.3390/ijms26125615 - 11 Jun 2025
Viewed by 401
Abstract
This study presents the first comprehensive theoretical investigation of the antioxidant mechanisms of trans-isoferulic acid against hydroperoxyl (HOO) radicals in aqueous solution, using the DFT/M062X/6-311+G(d,p)/PCM method. Thermodynamic and kinetic parameters, including reaction energy barriers and bimolecular rate constants, were determined for [...] Read more.
This study presents the first comprehensive theoretical investigation of the antioxidant mechanisms of trans-isoferulic acid against hydroperoxyl (HOO) radicals in aqueous solution, using the DFT/M062X/6-311+G(d,p)/PCM method. Thermodynamic and kinetic parameters, including reaction energy barriers and bimolecular rate constants, were determined for the three major pathways: hydrogen transfer (HT), radical adduct formation (RAF), and single electron transfer (SET). The results indicate that, at physiological pH, the RAF mechanism is both more exergonic and approximately eight-times faster than HT. At a higher pH, where the phenolate anion dominates, antioxidant activity is enhanced by an additional fast, diffusion-limited SET pathway. Isoferulic acid was also found to effectively chelate Fe2+ ions at pH 7.4 and above, forming stable complexes that could inhibit Fenton-type hydroxyl radical generation. Moreover, its strong UV absorption suggests a role in limiting photo-induced free radical formation. These findings not only clarify the antioxidant behavior of isoferulic acid but also provide novel theoretical insights applicable to related phenolic compounds. The compound’s multi-target antioxidant profile highlights its potential as a photoprotective agent in sunscreen formulations. Full article
(This article belongs to the Special Issue New Advances of Free-Radical Reactions in Organic Chemistry)
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14 pages, 1184 KiB  
Article
Quantification of Phenolic Compounds by HPLC/DAD and Evaluation of the Antioxidant, Antileishmanial, and Cytotoxic Activities of Ethanolic Extracts from the Leaves and Bark of Sarcomphalus joazeiro (Mart.)
by Natália Kelly Gomes de Carvalho, Débora Odília Duarte Leite, Aracélio Viana Colares, Fernando Almeida Souza, Kátia da Silva Calabrese, Gerson Javier Torres Salazar, Joice Barbosa do Nascimento, Mariana Pereira da Silva, Fabiola Fernandes Galvão Rodrigues and José Galberto Martins da Costa
Plants 2025, 14(11), 1733; https://doi.org/10.3390/plants14111733 - 5 Jun 2025
Viewed by 524
Abstract
Sarcomphalus joazeiro (Mart.) is a promising candidate for the formulation of new therapies against parasitic infections. This study aimed to quantify the content of phenolic compounds and evaluate the antioxidant, antileishmanial, and cytotoxic potential of ethanolic extracts of the leaves (EELSJ) and bark [...] Read more.
Sarcomphalus joazeiro (Mart.) is a promising candidate for the formulation of new therapies against parasitic infections. This study aimed to quantify the content of phenolic compounds and evaluate the antioxidant, antileishmanial, and cytotoxic potential of ethanolic extracts of the leaves (EELSJ) and bark (EEBSJ) of S. joazeiro. Quantification of phenolic acids (caffeic acid, p-coumaric acid, ferulic acid, cinnamic acid) and flavonoids (naringenin, pinocembrin, and apigenin) was performed by high-performance liquid chromatography with a diode array detector (HPLC-DAD). The extracts were subjected to antioxidant assays, including Fe3+ reduction, Fe2+ chelation, and inhibition of oxidative degradation of deoxyribose (2-DR). The antileishmanial activity was evaluated against promastigote forms of Leishmania amazonensis, while cytotoxicity was assessed in J774.G8 macrophages. Among the biological effects evaluated, EELSJ showed potent hydroxyl radical (•OH) scavenging activity, with IC50 < 10 µg/mL, which potentially correlates with its phenolic acid and flavonoid content (0.7066 mg/g). In comparison, EEBSJ showed a lower phenolic content (0.197 mg/g) and demonstrated Fe2+ chelating activity (IC50 = 14.96 ± 0.0477 µg/mL). EELSJ also exhibited antileishmanial activity against L. amazonensis (IC50 = 246.20 µg/mL), with low cytotoxicity (CC50 = 343.3 µg/mL; SI = 1.39), whereas EEBSJ showed minimal antileishmanial effect and marked cytotoxicity toward J774.G8 macrophages (CC50 = 5.866 µg/mL). The leaves of S. joazeiro stand out as the most promising plant organ for future investigations. Future studies should focus on investigating their action mechanisms in more detail. Full article
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26 pages, 2448 KiB  
Review
Iron-Mediated Overexpression of Amyloid Precursor Protein via Iron Responsive mRNA in Alzheimer’s Disease
by Mateen A. Khan
Int. J. Mol. Sci. 2025, 26(11), 5283; https://doi.org/10.3390/ijms26115283 - 30 May 2025
Cited by 1 | Viewed by 587
Abstract
Iron accumulation in the brain is widespread in Alzheimer’s disease (AD), the most common cause of dementia. According to numerous studies, too much iron triggers the development of neurofibrillary tangles (NFTs) and amyloid-β (Aβ) plaques, both of which accelerate the onset of AD. [...] Read more.
Iron accumulation in the brain is widespread in Alzheimer’s disease (AD), the most common cause of dementia. According to numerous studies, too much iron triggers the development of neurofibrillary tangles (NFTs) and amyloid-β (Aβ) plaques, both of which accelerate the onset of AD. Iron sequestration and storage were disrupted by high iron, and the pattern of interaction between iron regulatory proteins (IRPs) and iron-responsive elements (IREs) was altered. The 5′-untranslated regions (5′-UTRs) of their APP mRNA transcripts have an IRE stem-loop, which is where iron influx enhances the translation of the amyloid precursor protein (APP). Iron regulated APP expression via the release of the repressor interaction of APP mRNA with IRP1 by a pathway similar to the iron control translation of the ferritin mRNA by the IREs in their 5′-UTRs. This leads to an uncontrolled buildup of redox active Fe2+, which exacerbates neurotoxic oxidative stress and neuronal death. Fe2+ overload upregulates the APP expression and increases the cleavage of APP and the accumulation of Aβ in the brain. The level of APP and Aβ, and protein aggregates, can be downregulated by IRPs, but are upregulated in the presence of iron overload. Therefore, the inhibition of the IRE-modulated expression of APP or Fe2+ chelation offers therapeutic significance to AD. In this article, I discuss the structural and functional features of IRE in the 5′-UTR of APP mRNA in relation to the cellular Fe2+ level, and the link between iron and AD through the amyloid translational mechanism. Although there are currently no treatments for AD, a progressive neurodegenerative disease, there are a number of promising RNA inhibitor and Fe2+ chelating agent therapeutic candidates that have been discovered and are being validated in April 2025 clinical trials. Future studies are expected to further show the therapeutic efficacy of iron-chelating medications, which target the APP 5′-UTR and have the ability to lower APP translation and, consequently, Aβ levels. As a result, these molecules have a great deal of promise for the development of small-molecule RNA inhibitors for the treatment of AD. Full article
(This article belongs to the Special Issue Molecular Insight into Alzheimer’s Disease)
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13 pages, 2515 KiB  
Article
Ferric-Chelate Reductase FRO3 Is Involved in Iron Homeostasis in Table Grape and Enhanced Plant Tolerance to Iron-Deficient Conditions
by Jianping Wang, Chenxiao Wang, Yutong Cui, Matthew Shi, Meiling Tang and Zhizhong Song
Int. J. Mol. Sci. 2025, 26(11), 5172; https://doi.org/10.3390/ijms26115172 - 28 May 2025
Viewed by 392
Abstract
In plants, ferric-chelate reductase (FRO) plays a critical role in mediating extracellular iron (Fe) reduction, a process essential for cellular Fe homeostasis and abiotic stress tolerance. However, the biological functions and regulatory mechanisms of FRO proteins in fruit crops remain poorly characterized. Here, [...] Read more.
In plants, ferric-chelate reductase (FRO) plays a critical role in mediating extracellular iron (Fe) reduction, a process essential for cellular Fe homeostasis and abiotic stress tolerance. However, the biological functions and regulatory mechanisms of FRO proteins in fruit crops remain poorly characterized. Here, six VvFRO genes were identified in the table grape cultivar ‘Yanhong’. Transcriptional analysis revealed that root expression of these genes was mainly induced under Fe deficiency, Fe depletion, NaCl stress, and PEG-induced drought stress, respectively, but remained unchanged by low temperature (4 °C) or heat treatment (45 °C). Among them, VvFRO3 exhibited the highest constitutive expression, predominantly in leaves, and was significantly up-regulated under Fe deficiency, Fe depletion, or NaCl treatment. Functional complementation assays demonstrated that heterologous overexpression of VvFRO3 in the Arabidopsis thaliana fro2 knockout mutant rescued its growth retardation phenotype, particularly under Fe-deficient conditions. This study advances our understanding of Fe uptake, transport, and homeostasis mechanisms in perennial fruit crops. Full article
(This article belongs to the Special Issue Advance in Plant Abiotic Stress: 3rd Edition)
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16 pages, 1738 KiB  
Article
Biosynthesis and Bioactivity of Melanin from the Deep-Sea Hydrothermal Vent Yeast Hortaea werneckii Mo34
by Hui-Juan Li and Zhen-Ming Chi
J. Mar. Sci. Eng. 2025, 13(6), 1004; https://doi.org/10.3390/jmse13061004 - 22 May 2025
Viewed by 351
Abstract
Importance of this study: Melanin synthesized through the oxidative polymerization of phenolic compounds exhibits a high molecular weight and has many physiological functions and activities. Main results: In this study, the key PKS1-1, PKS1-2, CMR1-1, and CMR1-2 genes [...] Read more.
Importance of this study: Melanin synthesized through the oxidative polymerization of phenolic compounds exhibits a high molecular weight and has many physiological functions and activities. Main results: In this study, the key PKS1-1, PKS1-2, CMR1-1, and CMR1-2 genes for melanin biosynthesis and regulation from the highly genome-duplicated black yeast Hortaea werneckii Mo34, isolated from a deep-sea hydrothermal vent, were heterologously complemented in the ∆pks1 albino mutant K5 and the ∆cmr1 albino mutant CM7-2 of Aureobasidium melanogenum XJ5-1. Melanin formation in all the resulting transformants was restored, confirming that both the PKS1-1 and PKS1-2 genes from H. werneckii Mo34 were likely involved in the DHN melanin biosynthesis of A. melanogenum XJ5-1. Furthermore, the CMR1-1 and CMR1-2 genes from H. werneckii Mo34 could play significant roles in regulating melanin biosynthesis in A. melanogenum XJ5-1. Simultaneously, the expression of the PKS1 and THR1 genes involved in melanin biosynthesis was also enhanced in the transformants complemented with the CMR1-1 and CMR1-2 genes. The purified high-molecular-weight melanin from H. werneckii Mo34 exhibited excellent Fe2⁺-chelating, DPPH radical-scavenging, and superoxide radical-scavenging activities. Additionally, it actively inhibited the growth of Staphylococcus aureus and Pseudomonas putida. Conclusions: The black yeast H. werneckii Mo34 indeed had the DHN melanin biosynthesis pathway and the melanin produced by it had many potential applications. Full article
(This article belongs to the Section Marine Biology)
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