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Antioxidant Research in Chile

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A special issue of Antioxidants (ISSN 2076-3921).

Deadline for manuscript submissions: 20 April 2025 | Viewed by 16803

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Special Issue Editor

Prof. Dr. Rodrigo Iturriaga

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Guest Editor

Instituto de Ciencias Biomédicas, Universidad Autonoma de Chile, Santiago 7500912, Chile
Interests: carotid body chemoreceptors; intermittent hypoxia; oxidative stress; inflammation; cardiorespiratory control

Special Issue Information

Dear Colleagues,

Chilean scientists produce quality research in several areas of knowledge, including studies related to the science and technology of antioxidants. Indeed, studies performed by Chilean scientists on redox signals, oxidative stress and antioxidants have contributed to the generation of new knowledge in cellular and system physiology, physiopathology, and biomedicine. However, there are other areas that have produced excellent articles focused on economical plants such wine, maqui and berries. Marine biology is another critical area that has contributed to the study of natural antioxidants from algae. This Special Issue of the journal Antioxidants is a magnificent opportunity for the Chilean scientific community to publish their work in a highly visible journal, highlighting their contribution to this area. Therefore, we would like to invite the Chilean scientific community to send their contributions to their special number.

Prof. Dr. Rodrigo Iturriaga
Guest Editor

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Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Antioxidants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

antioxidants
biomedicine
nutrition
oxidative stress

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Research

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18 pages, 1736 KiB

Open AccessArticle

Drying: A Practical Technology for Blueberries (Vaccinium corymbosum L.)—Processes and their Effects on Selected Health-Promoting Properties

by Elsa Uribe, Antonio Vega-Galvez, Alexis Pasten, Kong Shun Ah-Hen, Nicol Mejias, Lorena Sepúlveda, Jacqueline Poblete and Luis S. Gomez-Perez

Antioxidants 2024, 13(12), 1554; https://doi.org/10.3390/antiox13121554 - 18 Dec 2024

Viewed by 522

Abstract

The global dried blueberry market is steadily growing, driven by the creation of innovative blueberry-based products. This trend presents an opportunity to explore a previously untapped segment of the blueberry market in Chile. In this study, a comprehensive assessment of four drying techniques (hot-air drying [HAD], vacuum drying [VD], infrared drying [IRD], and freeze-drying [FD]) was conducted to determine best operating conditions and preserve the health-promoting properties of blueberries. Drying kinetics, proximate composition, color, anthocyanin content, individual phenols, and antioxidant, antiproliferative, and antidiabetic potential of blueberries were evaluated. VD showed the highest drying rates, reaching equilibrium moisture more rapidly (D_eff value of 3.44 × 10⁻¹⁰ m²/s). Drying caused an increase in lipid content but a decrease in protein content. The color parameter L* increased in all dried samples, and C^* reflected color intensification. FD best retained anthocyanin content, which decreased significantly in the other drying processes. Chlorogenic acid and rutin predominated in HAD, IRD, and FD samples. The antioxidant potential in ORAC assays increased for all drying methods but decreased in DPPH assays. Blueberry extracts from FD and HAD exhibited the greatest antiproliferative effect against A549 and H1299 cell lines, respectively. HAD showed the best inhibitory effect on α-glucosidase, with an IC50 value of 0.276 mg/mL, similar to acarbose (IC50 = 0.253 mg/mL). Given the significant retention of health-promoting properties and bioactive compounds in HAD-dried samples, this method is advisable as a sustainable option for drying blueberries in Chile. Full article

(This article belongs to the Special Issue Antioxidant Research in Chile)

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Figure 1

Figure 1
(A) Effects of drying methods on the moisture ratio (MR) versus drying time curve of blueberries. (B) Drying rate (DR) versus drying time curve for blueberries with different drying methods. Values are the means of triplicate analyses (n = 3), and error bars are the standard deviation. Hot-air drying (HAD), vacuum drying (VD), infrared drying (IRD), and freeze-drying (FD). Full article ">Figure 2
Qualitative analytical results of the phenolic profile in (A) control and (B) representative dried samples of blueberries by HPLC-DAD. 1 Protocatechuic acid; 2 Chlorogenic acid; 3 Epigallocatechin; 4 Caffeic acid; 5 Rutin; 6 Naringin; 7 Quercetin. Full article ">Figure 3
Antioxidant potential of blueberries as affected by drying methods: (A) 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and (B) Oxygen Radical Absorbance Capacity (ORAC) assays. Values are the means of triplicate analyses (n = 3), and error bars are the standard deviation. TE: Trolox equivalents. Different alphabet letters presented on the bars indicate significant differences at p < 0.05 among different drying methods. Hot-air drying (HAD), vacuum drying (VD), infrared drying (IRD), and freeze-drying (FD). Full article ">Figure 4
Antiproliferative effects estimated at various concentrations of extracts obtained from blueberries dried by different methods against (A) H1299 cell lines and (B) A549 cell lines. Data are expressed as mean ± SEM of three independent experiments (n = 3). Hot-air drying (HAD), vacuum drying (VD), infrared drying (IRD), and freeze-drying (FD). Full article ">Figure 5
α-Glucosidase inhibitory activity estimated at various concentrations of extracts obtained from blueberries dried by different methods. Acarbose is a known anti-diabetic drug (positive control). Values are the means of triplicate analyses (n = 3), and error bars are the standard deviation. Hot-air drying (HAD), vacuum drying (VD), infrared drying (IRD), and freeze-drying (FD). Full article ">

18 pages, 1295 KiB

Open AccessArticle

Amyloid β-Oligomers Inhibit the Nuclear Ca²⁺ Signals and the Neuroprotective Gene Expression Induced by Gabazine in Hippocampal Neurons

by Pedro Lobos, Ignacio Vega-Vásquez, Barbara Bruna, Silvia Gleitze, Jorge Toledo, Steffen Härtel, Cecilia Hidalgo and Andrea Paula-Lima

Antioxidants 2023, 12(11), 1972; https://doi.org/10.3390/antiox12111972 - 6 Nov 2023

Cited by 2 | Viewed by 2045

Abstract

Hippocampal neuronal activity generates dendritic and somatic Ca²⁺ signals, which, depending on stimulus intensity, rapidly propagate to the nucleus and induce the expression of transcription factors and genes with crucial roles in cognitive functions. Soluble amyloid-beta oligomers (AβOs), the main synaptotoxins engaged in the pathogenesis of Alzheimer’s disease, generate aberrant Ca²⁺ signals in primary hippocampal neurons, increase their oxidative tone and disrupt structural plasticity. Here, we explored the effects of sub-lethal AβOs concentrations on activity-generated nuclear Ca²⁺ signals and on the Ca²⁺-dependent expression of neuroprotective genes. To induce neuronal activity, neuron-enriched primary hippocampal cultures were treated with the GABA_A receptor blocker gabazine (GBZ), and nuclear Ca²⁺ signals were measured in AβOs-treated or control neurons transfected with a genetically encoded nuclear Ca²⁺ sensor. Incubation (6 h) with AβOs significantly reduced the nuclear Ca²⁺ signals and the enhanced phosphorylation of cyclic AMP response element-binding protein (CREB) induced by GBZ. Likewise, incubation (6 h) with AβOs significantly reduced the GBZ-induced increases in the mRNA levels of neuronal Per-Arnt-Sim domain protein 4 (Npas4), brain-derived neurotrophic factor (BDNF), ryanodine receptor type-2 (RyR2), and the antioxidant enzyme NADPH-quinone oxidoreductase (Nqo1). Based on these findings we propose that AβOs, by inhibiting the generation of activity-induced nuclear Ca²⁺ signals, disrupt key neuroprotective gene expression pathways required for hippocampal-dependent learning and memory processes. Full article

(This article belongs to the Special Issue Antioxidant Research in Chile)

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Figure 1
AβOs addition induces fast cytoplasmic and slower nuclear Ca2+ signals in pyramidal hippocampal neurons. AβOs addition induces fast cytoplasmic and slower nuclear Ca2+ levels in pyramidal hippocampal neurons: (A) representative image showing the cytoplasmic fluorescence signals emitted by a hippocampal neuron loaded with Fluo-4 after treatment with 500 nM AβOs, at the maximum level of intensity recorded. Scale bar, 15 μm. A rainbow scale was used to show the fluorescence intensity of the Ca2+ indicator (black: low values; red: high values); (B) representative trace of changes over time in cytoplasmic Ca2+ levels recorded in a neuron loaded with Fluo-4, before (baseline) and after the addition of 500 nM AβOs at the indicated time (arrow); (C) representative image showing the nuclear fluorescence signals emitted by the nucleus of a neuron transfected with GCaMP3-NLS after the addition of 500 nM AβOs to primary hippocampal cultures, at the maximum level of intensity recorded. Scale bar, 20 μm. A rainbow scale was used to show the fluorescence intensity of the Ca2+ indicator (blue: low values; red: high values); and (D) representative trace of changes over time in nuclear Ca2+ levels recorded in a neuron transfected with GCaMP3-NLS before (baseline) and after the addition of 500 nM AβOs at the indicated time (arrow). Data are expressed as representative recordings from experiments performed with different hippocampal cultures; n = 3. Full article ">Figure 2
Gabazine addition to primary hippocampal neurons induces synchronized cytoplasmic (A,B) and nuclear Ca2+ signals (C,D). Gabazine induces synchronized cytoplasmic and nuclear Ca2+ signals in primary hippocampal neurons: (A) representative image showing the fluorescence signals emitted by the cytoplasmic Ca2+ sensor GCaMP5 (green); (B) representative trace showing the relative changes of the GCaMP5 sensor fluorescence signals recorded from the dendrites of neurons before (baseline) and after the addition of 5 μM GBZ to the culture, which caused synchronous oscillatory Ca2+ transients; (C) representative image showing the fluorescence signals emitted by the nuclear Ca2+ sensor GCaMP3-NLS (green) recorded in basal condition; two nuclei of hippocampal neurons are observed; and (D) traces of recordings of the relative changes of the signal intensity of GCaMP3-NLS, recorded in the nuclei illustrated in D before (baseline) and after the addition of 5 μM GBZ to a control culture at the indicated time (arrow). A and C, Scale bar: 20 μm. Data are expressed as representative recordings from experiments performed with different hippocampal cultures; n = 3. Full article ">Figure 3
Treatment with AβOs disrupts the transient nuclear Ca2+ signals induced by GBZ in pyramidal hippocampal neurons. Treatment with AβOs disrupts the transient nuclear Ca2+ signals induced by GBZ in pyramidal hippocampal neurons. Neurons were incubated for 6 h with AβOs (500 nM) before GBZ addition and the relative change in fluorescence with time values (Fmax − F0/F0) was recorded in the nucleus of neurons expressing GCaMP3-NLS. (A) The maximum amplitude (GBZ mean value = 0.95; AβOs mean value = 0.30) and (B) the frequency of the detected peaks were quantified (GBZ mean value = 38.5; AβOs mean value = 15.83); the average values obtained from five experiments performed in independent cultures show significant differences between GBZ addition to controls or to neurons preincubated with AβOs. Data are presented as Mean ± SE. In total, at least 50 neurons were analyzed per condition in five independent experiments (with different primary cultures). Statistical analysis was conducted using Student’s t-test. In (A,B), * p < 0.05; the exact p values were p = 0.040 and p = 0.037, respectively. Full article ">Figure 4
Treatment with AβOs prevents the CREB phosphorylation increase induced by GBZ in hippocampal neurons: (A) representative images of control hippocampal cultures and/or cultures pre-incubated for 6 h with 500 nM AβOs before the addition of GBZ. The images show that the signals originated from incubation with antibodies against phosphorylated CREB (p-CREB; green) and the neuronal marker MAP2 (red); cell nuclei were labeled with DAPI (blue). All images illustrate the sum of the fluorescence recorded in the z-axis of all confocal planes acquired by spinning-disk microscopy, with a 40× objective, scale bar 20 μm; and (B) quantification of the relative levels of p-CREB fluorescence detected in different conditions (AβOs mean value = 1.106; GBZ mean value = 3.093, and AβOs + GBZ mean value = 1.510). Bars represent Mean ± SE, n = 3. Statistically significant differences were evaluated by one-way ANOVA followed by Bonferroni’s post hoc test for multiple comparisons. * p < 0.05; ** p < 0.01 The exact p values from left to right are as follows: p = 0.003, p = 0.030, and p = 0.005. Full article ">Figure 5
Treatment with AβOs decreases or prevents the gabazine-induced increase in the mRNA levels of Npas4, RyR2, BDNF exon IV and the antioxidant enzyme Nqo1. The relative mRNA levels of Npas4 (mean fold change value from left to right 7.065; 91.43; 24.83) (A); RyR2 (mean fold change value from left to right 0.891; 1.736; 0.924) (B); BDNF exon IV (mean fold change value from left to right 0.507; 7.519; 2.753) (C); and Nqo1 (mean fold change value from left to right 0.572; 3.149; 0.668) (D) were determined by qPCR of primary neuronal cultures treated with GBZ for 2 h and incubated next for 6 h with 500 nM AβOs or saline. Values, normalized for β-actin mRNA levels, are expressed as fold over the values displayed by control cultures. Data are expressed as Mean ± SE; n = 5. Statistical analysis was performed with ANOVA followed by Tukey’s post hoc test for multiple comparisons. * p < 0.05; ** p < 0.01; *** p < 0.001. The exact p values from left to right are as follows p = 0.0002 and p = 0.0311 for (A); p = 0.0090; p = 0.0130 and p = 0.0246 for (B); p < 0.001; p < 0.001; p = 0.0391 for (C); p = 0.0133; and p = 0.0391 for (D). Full article ">

14 pages, 4234 KiB

Open AccessArticle

Transcriptional Profiling of Human Endothelial Cells Unveils PIEZO1 and Mechanosensitive Gene Regulation by Prooxidant and Inflammatory Inputs

by German A. Arenas, Jose G. Valenzuela, Estefanía Peñaloza, Adolfo A. Paz, Rodrigo Iturriaga, Claudia G. Saez and Bernardo J. Krause

Antioxidants 2023, 12(10), 1874; https://doi.org/10.3390/antiox12101874 - 17 Oct 2023

Cited by 2 | Viewed by 3324

Abstract

PIEZO1 is a mechanosensitive cation channel implicated in shear stress-mediated endothelial-dependent vasorelaxation. Since altered shear stress patterns induce a pro-inflammatory endothelial environment, we analyzed transcriptional profiles of human endothelial cells to determine the effect of altered shear stress patterns and subsequent prooxidant and inflammatory conditions on PIEZO1 and mechanosensitive-related genes (MRG). In silico analyses were validated in vitro by assessing PIEZO1 transcript levels in both the umbilical artery (HUAEC) and vein (HUVEC) endothelium. Transcriptional profiling showed that PIEZO1 and some MRG associated with the inflammatory response were upregulated in response to high (15 dyn/cm²) and extremely high shear stress (30 dyn/cm²) in HUVEC. Changes in PIEZO1 and inflammatory MRG were paralleled by p65 but not KLF or YAP1 transcription factors. Similarly, PIEZO1 transcript levels were upregulated by TNF-alpha (TNF-α) in diverse endothelial cell types, and pre-treatment with agents that prevent p65 translocation to the nucleus abolished PIEZO1 induction. ChIP-seq analysis revealed that p65 bonded to the PIEZO1 promoter region, an effect increased by the stimulation with TNF-α. Altogether this data showed that NF-kappa B activation via p65 signaling regulates PIEZO1 expression, providing a new molecular link for prooxidant and inflammatory responses and mechanosensitive pathways in the endothelium. Full article

(This article belongs to the Special Issue Antioxidant Research in Chile)

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Figure 1

Figure 1
High shear stress regulates PIEZO1 and mechanotransduction-related gene (MRG) levels in HUVEC. (A) Hierarchical clustering of HUVEC samples exposed to static, 15 dyn/cm2, and 30 dyn/cm2 in vitro shear stress. (B) Correlation graph for 15 dyn/cm2 and 30 dyn/cm2 exposed HUVEC. Black dots represent similar gene regulation patterns between groups. Red dots represent different gene regulation between groups. (C) Transcription factor enrichment in DEG in HUVEC exposed to 15 dyn/cm2 and 30 dyn/cm2. (D) Fold change in PIEZO1 transcript levels in HUVEC exposed to static, 15 dyn/cm2, and 30 dyn/cm2 in vitro shear stress (E) Average expression heat map for MRG in HUVEC exposed to different shear stress levels. Values are expressed as mean ± S.E.M., * p < 0.05, one-way ANOVA, FDR post hoc test. Full article ">Figure 2
Effect of silencing shear stress-responsive genes on PIEZO1 and MRG transcript levels in HUVECs. (A) Average expression heatmap for mechanotransduction-related genes in HUVEC treated with siKLF4. (B) PIEZO1 transcript level fold change in HUVEC treated with siKLF4. (C) Average expression heatmap for mechanotransduction-related genes in HUVEC treated with siYAP. (D) PIEZO1 transcript level fold change in HUVEC treated with siYAP. Values are expressed as mean ± S.E.M., * p < 0.05, Mann–Whitney U test. Full article ">Figure 3
TNF-α increases PIEZO1 and mechanosensing-related transcript levels in diverse EC. (A) Fold change heatmap for mechanotransduction-related genes in HUVECs treated with TNF-α, 25 ng/mL (1 h), and 10 and 50 ng/mL (24 h). (B) PIEZO1 transcript level fold changes in response to TNF-α treatments at different times and concentrations. (C) Time-lapse curves representing selected transcript level changes in response to 480 min of TNF-α (10 ng/mL) treatment. (D) Dots graph representing the correlation between PIEZO1 and RELA transcript levels during time-lapse shown in (C). Values are represented as fold changes related to the basal from one sample from each data point. Values are expressed as mean ± S.E.M., * p < 0.05, one-way ANOVA, FDR post hoc test. Full article ">Figure 4
Effects of TNF-α stimulation on MRG and PIEZO1 transcript levels in endothelial cells from different vascular origins. (A) Hierarchical clustering of diverse endothelial cells exposed to different TNF-α treatments; (B) t-SNE projection showing clustering between diverse endothelial cell types and conditions. Endothelial cells exposed to TNF-α are represented in red, orange, and pink colors. Endothelial cells under basal conditions (control) are represented in blue and light blue colors. (C) Graph bars show seven enriched pathways in response to TNF-alpha treatment in diverse endothelial cells. (D,E) Fold change of PIEZO1 transcript levels in response to TNF-α treatment (50 ng/mL) for 24 h in HUVEC and HUAEC, respectively. Values are expressed as mean ± S.E.M., * p < 0.05 to control, Mann–Whitney U test. Full article ">Figure 5
Interaction of PIEZO1/RELA and the effects of NF-kB inhibitors on TNF-α-induced PIEZO1 expression. (A) Predicted binding sites for NF-κB in the PIEZO1 promoter region zone (TSS: transcription start site; 1000 bp). (B) ChIP-seq diagram representing p65 interaction with PIEZO1 promoter region in control and treated cells. The overlay shows graphical differences between conditions. (C) ChIP-seq diagram representing Pol II interaction with PIEZO1 promoter in control and treated cells. The overlay shows no qualitative differences between conditions. (D) Fold change in PIEZO1 transcript levels in response to TNF-α treatment (10 ng/mL) for 24 h alone or with NOD, a p65 inhibitor. (E) Fold change in PIEZO1 transcript levels in response to TNF-α treatment (50 ng/mL) for 24 h alone or with CORM-3, a CO-donor, and p65 inhibitor. (F) Fold change in PIEZO1 transcript levels in response to TNF-α treatment (25 ng/mL) for 1 h alone or with JQ1, a BRD4 inhibitor. Values are expressed as mean ± S.E.M., * p < 0.05 to control, # p < 0.05 to TNF-α treated, one-way ANOVA, FDR post hoc test. Full article ">Figure 6
Summary of proposed PIEZO1 regulation by pro-inflammatory conditions in in vitro endothelial cells. TNF-α receptor activation by TNF-α led to NF-κB complex p65-p50 subunit activation and translocation to the nucleus after IkB-alpha ubiquitination. Cytoplasmic levels and activity of p65 are reduced by NOD and CORM-3, respectively. NOD also reduces nuclear p65 levels. BRD4, a transcriptional NF-κB enhancer, is inhibited by JQ1, but no effect in the regulation of PIEZO1 transcription was found. This diagram is simplified and does not consider every TNF-α signaling pathway (created in Biorender.com). Full article ">

18 pages, 1457 KiB

Open AccessArticle

Processing of Enriched Pear Slices with Blueberry Juice: Phenolics, Antioxidant, and Color Characteristics

by Siluana Katia Tischer Seraglio, Belkis Sarahí Hernández-Velásquez, Moira Elizabeth Osses-Millar, Bárbara Yolanda Malverde-Muñoz, María Estuardo Guerra-Valle, Constanza Pavez-Guajardo and Jorge Moreno

Antioxidants 2023, 12(7), 1408; https://doi.org/10.3390/antiox12071408 - 11 Jul 2023

Cited by 5 | Viewed by 1692

Abstract

This study evaluated the effectiveness of phenolic compound incorporation from blueberry juice into pear slices (PS) using a combination of ohmic heating (OH) and vacuum impregnation (VI), followed by air-drying (AD) or freeze-drying (FD). Our results showed that OH increased the content of bioactive compounds and antioxidant capacity of blueberry juice, with the optimal OH condition set at 50 °C for 20 min under an electric field of 13 V·cm⁻¹. Furthermore, the combination of VI and OH was efficient in enriching PS with bioactive compounds from blueberry juice (such as cyanidin and epigallocatechin), with the optimal VI/OH condition set at 50 °C for 90 min under an electric field of 7.8 V·cm⁻¹. Moreover, anthocyanin pigments from blueberry juice affected the color parameters of PS by increasing the a* parameter and decreasing the b* and L* parameters. However, both FD and AD (at 40, 50, and 60 °C) negatively affected (p ≤ 0.05) the phenolic content and antioxidant capacity. Notably, AD at 60 °C showed the highest levels of phenolic compounds and antioxidant potential for both impregnated and non-impregnated PS. Full article

(This article belongs to the Special Issue Antioxidant Research in Chile)

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Full article ">Figure 1
The process applied to obtain the pear slices (PS) impregnated by vacuum impregnation (VI), followed by ohmic heating (OH), and dried and non-dried by freeze-drying (FD) and air-drying (AD): PS treated by VI/OH and non-dried (PS-VI/OH) and dried by freeze-drying (FD-VI/OH) and air-drying at 40, 50, and 60 °C (AD40-VI/OH, AD50-VI/OH, and AD60-VI/OH). Control samples: PS non-treated by VI/OH and non-dried (PS-non-VI/OH) and dried by freeze-drying (FD-non-VI/OH) and air-drying at 40, 50, and 60 °C (AD40-non-VI/OH, AD50-non-VI/OH, and AD60-non-VI/OH). Full article ">Figure 2
Effect of ohmic heating on blueberry juice throughout 20 min at 30, 40, and 50 °C: (a) total phenolic content (TPC); (b) total flavonoid content (TFC); (c) total monomeric anthocyanin content (TMA); (d) DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay; and (e) ferric reducing antioxidant power (FRAP). GAE—gallic acid equivalent. CE—catechin equivalent. C3G—cyanidin 3-glucoside equivalent. TE—Trolox equivalent. DM—dry matter. Results are presented as mean ± standard deviation. Full article ">Figure 3
Effect of vacuum impregnation assisted by ohmic heating on pear slices enriched with blueberry juice throughout 180 min at 30, 40, and 50 °C: (a) total phenolic content (TPC); (b) total flavonoid content (TFC); (c) total monomeric anthocyanin content (TMA); (d) DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay; and (e) ferric reducing antioxidant power (FRAP). GAE—gallic acid equivalent. CE—catechin equivalent. C3G—cyanidin 3-glucoside equivalent. TE—Trolox equivalent. DM—dry matter. Results are presented as mean ± standard deviation. Full article ">

Review

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15 pages, 759 KiB

Open AccessReview

Antimicrobial, Antioxidant, and Anti-Inflammatory Properties of Monofloral Honeys from Chile

by Erick Poulsen-Silva, Felipe Gordillo-Fuenzalida, Patricia Velásquez, Felipe M. Llancalahuen, Rodrigo Carvajal, Mauricio Cabaña-Brunod and María Carolina Otero

Antioxidants 2023, 12(9), 1785; https://doi.org/10.3390/antiox12091785 - 21 Sep 2023

Cited by 7 | Viewed by 3398

Abstract

Honey is a mixture of compounds produced by bees that has been appreciated by humanity since the creation of the oldest civilizations. It has multiple uses and can be a highly nutritional and healing substance. It has been used in traditional medicine as a natural alternative for the treatment of diverse clinical conditions. This is due to its reported bioactive properties. The objective of this article is to exhibit and analyze the biological properties of different types of honey originating from Chile based on their antimicrobial, antioxidant, and anti-inflammatory activities, focusing primarily on recompiling experimental studies made on monofloral honey of plant species present in the Chilean territory. The result of this bibliographical review shows that Chilean honey possesses remarkable bioactive properties, mainly antimicrobial and antioxidant activities, with a few studies on its anti-inflammatory activity. Most of these results were attributed to monofloral honey belonging to ulmo (Eucryphia cordifolia) and quillay (Quillaja saponaria Molina) plant species. These properties are related to the presence of several bioactive components, such as phenolic components (mainly flavonoids), hydrogen peroxide (H₂O₂), enzymes, proteins, and carbohydrates. The biodiversity of the flora and the environmental conditions of the Chilean territory are responsible for the wide range of bioactive compounds and biological properties found in Chilean honey. Further studies must be made to uncover the medicinal potential of these native honeys. Full article

(This article belongs to the Special Issue Antioxidant Research in Chile)

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34 pages, 6247 KiB

Open AccessReview

Potential Role of Natural Antioxidants in Countering Reperfusion Injury in Acute Myocardial Infarction and Ischemic Stroke

by Sofía Orellana-Urzúa, Camilo Briones-Valdivieso, Silvia Chichiarelli, Luciano Saso and Ramón Rodrigo

Antioxidants 2023, 12(9), 1760; https://doi.org/10.3390/antiox12091760 - 13 Sep 2023

Cited by 17 | Viewed by 4788

Abstract

Stroke and acute myocardial infarction are leading causes of mortality worldwide. The latter accounts for approximately 9 million deaths annually. In turn, ischemic stroke is a significant contributor to adult physical disability globally. While reperfusion is crucial for tissue recovery, it can paradoxically exacerbate damage through oxidative stress (OS), inflammation, and cell death. Therefore, it is imperative to explore diverse approaches aimed at minimizing ischemia/reperfusion injury to enhance clinical outcomes. OS primarily arises from an excessive generation of reactive oxygen species (ROS) and/or decreased endogenous antioxidant potential. Natural antioxidant compounds can counteract the injury mechanisms linked to ROS. While promising preclinical results, based on monotherapies, account for protective effects against tissue injury by ROS, translating these models into human applications has yielded controversial evidence. However, since the wide spectrum of antioxidants having diverse chemical characteristics offers varied biological actions on cell signaling pathways, multitherapy has emerged as a valuable therapeutic resource. Moreover, the combination of antioxidants in multitherapy holds significant potential for synergistic effects. This study was designed with the aim of providing an updated overview of natural antioxidants suitable for preventing myocardial and cerebral ischemia/reperfusion injuries. Full article

(This article belongs to the Special Issue Antioxidant Research in Chile)

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Role of oxidative stress in myocardial damage caused by ischemia followed by reperfusion. The increase in cytosolic calcium is associated with the activation of XO, which is an enzyme with pro-oxidant properties. The increase in calcium inside the mitochondria and the increase in pH during reperfusion lead to the opening of the mPTP, which causes the decrease in the mitochondrial transmembrane potential linked to ROS generation. These reactive oxygen molecules activate the transcription factor NF-κB, promoting inflammation and neutrophil migration to the injured region as well as increasing ROS production by NADPH oxidase. Also, ROS originates from uncoupled eNOS, oxidizing lipids, proteins, and DNA, triggering cell death. In addition, apoptosis is induced by the release of cytochrome c via mPTP, whereas ferroptosis is inducted by reduced GSH and GPX4 activity, leading to the accumulation of lipid peroxidation products. Furthermore, miR-132 directly targets SIRT1 and negatively regulates its expression, leading to a decrease in Nrf2 transcription, which in turn results in diminished antioxidant capacity; Ca2+: calcium; DNA: deoxy-ribonucleic acid; NF-κB: nuclear factor kappa B; eNOS: endothelial nitric oxide synthase; O2•−: superoxide anion; NOX: NADPH oxidases; TNFα: tumor necrosis factor-alpha; IL-6: interleukin 6; IL-1: interleukin 1; miR-132: microRNA-132; SIRT1: sirtuin 1; Nrf2: nuclear factor erythroid 2-related factor 2. Full article ">Figure 2
Role of oxidative stress in brain damage caused by ischemia followed by reperfusion. ATP: adenosine triphosphate; Na+: sodium; K+: potassium; Ca2+: calcium; ROS: reactive oxygen species; ADS: antioxidant defense system; BBB: blood–brain barrier; NF-κB: nuclear factor kappa B. Full article ">Figure 3
Antioxidant protective pathways involved in counteracting reperfusion injury. Nrf2: nuclear factor erythroid 2-related factor 2; PI3K: phosphoinositide 3-kinase; AKT: protein kinase B; ARE: antioxidant response elements; SIRT1: sirtuin 1; CAT: catalase; factor-alpha; NF-κB: nuclear factor kappaB; Ca2+: calcium; eNOS: endothelial nitric oxide synthase; iNOS: inducible nitric oxide synthase; NADPH oxidase: nicotinamide adenine dinucleotide phosphate oxidase; ROS: reactive oxygen species; SOD: superoxide dismutase; TNF-α: tumor necrosis factor alpha; GPX: glutathione peroxidase; HMT1: type 1 arginine methyltransferase; TfR1: transferrin receptor protein 1. Full article ">

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