Oxygen

Research

18 pages, 3843 KiB

Open AccessArticle

Extraction of Bioactive Compounds from Cistus creticus Leaves and Their Use in the Preparation of Yogurt Desserts

by Dimitrios Palaiogiannis, Vassilis Athanasiadis, Theodoros Chatzimitakos, Martha Mantiniotou, Eleni Bozinou, Dimitris P. Makris and Stavros I. Lalas

Oxygen 2024, 4(1), 90-107; https://doi.org/10.3390/oxygen4010005 - 12 Feb 2024

Viewed by 1407

Abstract

The objective of this study was to determine the optimal conditions for the recovery of bioactive and antioxidant compounds in aqueous solutions of Cistus creticus leaves and then employ the optimal extract for the enrichment of yogurt samples. The optimal conditions were established [...] Read more.

The objective of this study was to determine the optimal conditions for the recovery of bioactive and antioxidant compounds in aqueous solutions of Cistus creticus leaves and then employ the optimal extract for the enrichment of yogurt samples. The optimal conditions were established by a response surface methodology and were determined to be a liquid-to-solid ratio of 48 mL/g at 76 °C for 41 min. The optimum extract yielded TPC 157.17 mg GAE/g dw and TFC 2.38 mg QE/g dw, while FRAP and DPPH values were 1258.52 and 933.67 μmol AAE/g dw, respectively. HPLC-DAD was utilized to identify and quantify specific polyphenols, like myricetin rhamnoside, in the extract. The optimal extract was then added to yogurt desserts during their preparation at three different concentrations to study how the physicochemical characteristics of the yogurt, as well as the antioxidant capacity added during enrichment, were affected. Statistical analysis of the results was carried out in order to obtain more valid data. It seems that the most suitable concentration for yogurt fortification was 0.1% w/v of the extract as, at this concentration, the yogurts exhibited higher antioxidant capacity, and their physicochemical characteristics were improved. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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18 pages, 541 KiB

Open AccessArticle

Study of the Total Phenolic Content, Total Antioxidant Activity and In Vitro Digestibility of Novel Wheat Crackers Enriched with Cereal, Legume and Agricultural By-Product Flours

by Despina Chatziharalambous, Chrysoula Kaloteraki, Panagiota Potsaki, Olga Papagianni, Konstantinos Giannoutsos, Danai I. Koukoumaki, Dimitris Sarris, Konstantinos Gkatzionis and Antonios E. Koutelidakis

Oxygen 2023, 3(2), 256-273; https://doi.org/10.3390/oxygen3020017 - 16 Jun 2023

Cited by 5 | Viewed by 2294

Abstract

Wheat-flour crackers represent a staple snack option, although they lack nutritional value. Agricultural by-products such as olive and grape seeds, cereals such as barley and legumes such as lupine and chickpea are rich in bioactive compounds; therefore, flours obtained from those could represent [...] Read more.

Wheat-flour crackers represent a staple snack option, although they lack nutritional value. Agricultural by-products such as olive and grape seeds, cereals such as barley and legumes such as lupine and chickpea are rich in bioactive compounds; therefore, flours obtained from those could represent a better option for bakery products fortification. The purpose of the present study was the investigation of total phenolic content and antioxidant activity before and after the baking of wheat crackers enriched with 10–30% olive seed, 10–30% grape seed, 10–40% lupine, 10–30% barley and 20–60% and 80% chickpea flours and the evaluation of the predicted bioavailability after in vitro digestion of crackers demonstrating the highest values. Crackers and doughs were processed and analyzed using Folin–Ciocâlteu and ferric reducing antioxidant power (FRAP) assays, respectively. Crackers with the highest properties were subjected to in vitro gastrointestinal digestion. Baking resulted in an increase in total phenolics and antioxidant activity in the majority of crackers. Olive and grape seed flour crackers demonstrated the highest antioxidant properties. Following in vitro digestion, 30% olive seed flour crackers retained the majority of polyphenols and antioxidant activity. Crackers enriched with 30% olive seed flour could represent a healthy functional bakery snack regarding their increased antioxidant properties. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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13 pages, 2527 KiB

Open AccessArticle

Impacts of Varying Blood Flow Restriction Cuff Size and Material on Arterial, Venous and Calf Muscle Pump-Mediated Blood Flow

by Steven B. Machek, Dillon R. Harris, Jeffery L. Heileson, Dylan T. Wilburn, Jeffrey S. Forsse and Darryn S. Willoughby

Oxygen 2023, 3(2), 190-202; https://doi.org/10.3390/oxygen3020014 - 20 May 2023

Cited by 4 | Viewed by 2179

Abstract

Blood flow restriction (BFR) may become ineffective or potentially dangerous without sufficient standardization. The purpose of this investigation was therefore to (1) assess the viability of multiple sizes of a novel BFR cuff to determine arterial occlusion pressure (AOP) and (2) compare resting [...] Read more.

Blood flow restriction (BFR) may become ineffective or potentially dangerous without sufficient standardization. The purpose of this investigation was therefore to (1) assess the viability of multiple sizes of a novel BFR cuff to determine arterial occlusion pressure (AOP) and (2) compare resting arterial, venous and calf muscle pump (cMP)-mediated blood flow between the aforementioned conditions and a commonly employed wide-rigid, tourniquet-style cuff. In randomized, counter-balanced, and crossover fashion, 20 apparently healthy males (18–40 years) donned a widely employed wide-rigid (WR) cuff, along with the largest (NE) and manufacturer-recommended sizes (NER) of a novel narrow-elastic cuff. Participants subsequently assessed AOP, as well as (at 80%AOP) arterial, venous, and venous cMP flow relative to baseline values via ultrasound. All analyses were performed at a significance level of p < 0.05. Analyses revealed a significant condition effect for AOP (p < 0.001; η_p² = 0.907) whereby WR was significantly lower than both NE and NER; in addition, the latter two did not differ. Compared with baseline, there were no statistically significant differences between cuffs for either arterial or cMP-mediated blood flow. Unsurprisingly, no participants demonstrated venous blood flow at 80% AOP. These findings support the viability of a novel narrow-elastic BFR product, evidenced by consistent AOP acquisition and equivocal blood flow parameters. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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11 pages, 2489 KiB

Open AccessArticle

Mitochondria-Stimulating and Antioxidant Effects of Slovak Propolis Varieties on Bovine Spermatozoa

by Eva Tvrdá, Július Árvay, Michal Ďuračka and Miroslava Kačániová

Oxygen 2023, 3(2), 179-189; https://doi.org/10.3390/oxygen3020013 - 26 Apr 2023

Cited by 1 | Viewed by 1749

Abstract

Propolis is a natural honeybee product, which is known for its beneficial pharmacological effects and use in traditional medicine. This study aspired to investigate the chemical and antioxidant properties of five propolis specimens, followed by the analysis of their in vitro impact on [...] Read more.

Propolis is a natural honeybee product, which is known for its beneficial pharmacological effects and use in traditional medicine. This study aspired to investigate the chemical and antioxidant properties of five propolis specimens, followed by the analysis of their in vitro impact on bovine spermatozoa vitality and oxidative profile. Semen samples from 10 breeding bulls were incubated in the absence or presence of 50 µg/mL propolis extracts, and selected sperm quality parameters including motility, mitochondrial activity, cAMP concentration, NAD⁺/NADH ratio, reactive oxygen species (ROS) and superoxide production were assessed at 2 h and 24 h. Sperm motion behavior and mitochondrial function were stabilized particularly in the presence of propolis collected from Hrabské and Litpovský Hrádok, Slovakia. At the same time, all propolis specimens acted as significant ROS quenchers and stabilized the oxidative milieu of the sperm cultures. Our data suggest that propolis may stabilize the mitochondrial function of spermatozoa while preventing excessive oxidative insults, thereby showing the potential to sustain the sperm motility of extended semen. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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Review

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37 pages, 1365 KiB

Open AccessReview

The Thirty-Fifth Anniversary of K⁺ Channels in O₂ Sensing: What We Know and What We Don’t Know

by Asuncion Rocher and Philip I. Aaronson

Oxygen 2024, 4(1), 53-89; https://doi.org/10.3390/oxygen4010004 - 9 Feb 2024

Cited by 1 | Viewed by 2240

Abstract

On the thirty-fifth anniversary of the first description of O₂-sensitive K⁺ channels in the carotid body chemoreceptors O₂ sensing remains a salient issue in the literature. Whereas much has been learned about this subject, important questions such as the [...] Read more.

On the thirty-fifth anniversary of the first description of O₂-sensitive K⁺ channels in the carotid body chemoreceptors O₂ sensing remains a salient issue in the literature. Whereas much has been learned about this subject, important questions such as the identity of the specific K⁺ channel subtype(s) responsible for O₂ sensing by chemoreceptors and the mechanism(s) by which their activities are altered by hypoxia have not yet been definitively answered. O₂ sensing is a fundamental biological process necessary for the acute and chronic responses to varying environmental O₂ levels which allow organisms to adapt to hypoxia. Whereas chronic responses depend on the modulation of hypoxia-inducible transcription factors which determine the expression of numerous genes encoding enzymes, transporters and growth factors, acute responses rely mainly on the dynamic modulation of ion channels by hypoxia, causing adaptive changes in cell excitability, contractility and secretory activity in specialized tissues. The most widely studied oxygen-sensitive ion channels are potassium channels, but oxygen sensing by members of both the calcium and sodium channel families has also been demonstrated. Given the explosion of information on this topic, in this review, we will focus on the mechanisms of physiological oxygen chemotransduction by PO₂-dependent K⁺ channels, with particular emphasis on their function in carotid body chemoreceptor cells (CBCC) and pulmonary artery smooth muscle cells (PASMC), highlighting areas of consensus and controversy within the field. We will first describe the most well-established concepts, those reproduced in multiple laboratories, and then discuss selected observations or questions that remain unresolved, and that limit our progress in this field. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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30 pages, 1428 KiB

Open AccessReview

The Ion Channels Involved in Oxidative Stress-Related Gastrointestinal Diseases

by Maria Rosaria Miranda, Vincenzo Vestuto, Ornella Moltedo, Michele Manfra, Pietro Campiglia and Giacomo Pepe

Oxygen 2023, 3(3), 336-365; https://doi.org/10.3390/oxygen3030022 - 21 Aug 2023

Cited by 2 | Viewed by 2619

Abstract

The pathogenesis of various gastrointestinal (GI) disorders, including gastritis, ulcers, inflammatory bowel disease (IBD) and cancer, can be linked to oxidative stress. It is known that reactive species carry out a crucial role in the genesis and progression of these pathologies; however, the [...] Read more.

The pathogenesis of various gastrointestinal (GI) disorders, including gastritis, ulcers, inflammatory bowel disease (IBD) and cancer, can be linked to oxidative stress. It is known that reactive species carry out a crucial role in the genesis and progression of these pathologies; however, the contribution of ionic channels in their development is still under discussion. The function of ion channels in the gastrointestinal tract influences a variety of cellular processes. Acid-base balance, mucus layer, microbiota and mucosal blood flow are only some of the essential features for maintaining the mucosal integrity of the cellular barrier in the intestine, allowing for the preservation of proper permeability and ensuring tissue homeostasis. As the functional modulation of several ion channels is altered during oxidative stress conditions associated with gastrointestinal inflammation, this review focuses on contributing new insight into the roles of and the relationship between ion channels and oxidative stress in GI diseases. The association between ion channels and oxidative stress conditions could be used in diagnostics and the development of new pharmacological treatments for major gastrointestinal diseases. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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20 pages, 1678 KiB

Open AccessReview

The On/Off History of Hydrogen in Medicine: Will the Interest Persist This Time Around?

by Tyler W. LeBaron, Kinji Ohno and John T. Hancock

Oxygen 2023, 3(1), 143-162; https://doi.org/10.3390/oxygen3010011 - 14 Mar 2023

Cited by 8 | Viewed by 7021

Abstract

Over 2000 publications including more than 100 human studies seem to indicate that humans have only recently benefited from or known about the medical effects of H₂ within the past 15 years. However, we have unknowingly benefited from H₂ since the [...] Read more.

Over 2000 publications including more than 100 human studies seem to indicate that humans have only recently benefited from or known about the medical effects of H₂ within the past 15 years. However, we have unknowingly benefited from H₂ since the dawn of time, from H₂-producing bacteria to the use of naturally occurring hydrogen-rich waters. Moreover, the first writings on the therapeutic effects of H₂ date to around 1793. Since then, papers appeared sporadically in the literature every few decades but never exploded until Ohsawa et al. again demonstrated hydrogen’s therapeutic effects in 2007. This landmark paper appears to have been the spark that ignited the medical interest in hydrogen. Although H₂ was used in the 1880s to locate intestinal perforations, in the 1940s in deep sea diving, and in the 1960s to measure blood flow, H₂ was largely viewed as biologically inert. This review highlights the history of hydrogen in the genesis/evolution of life and its medicinal and non-medicinal use in humans. Although hydrogen medicine has a long and erratic history, perhaps future history will show that, this time around, these 15 years of ignited interest resulted in a self-sustaining explosion of its unique medical effects. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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Other

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13 pages, 3674 KiB

Open AccessPerspective

Oxygen in the Earth System

by Klemens Hocke

Oxygen 2023, 3(3), 287-299; https://doi.org/10.3390/oxygen3030019 - 27 Jun 2023

Cited by 1 | Viewed by 3781

Abstract

Atmospheric oxygen is produced and consumed by life on Earth, and the ozone layer protects life on Earth from harmful solar UV radiation. The research on oxygen in the Earth system is of interest to many different geoscientific communities, from paleoclimatology to aeronomy. [...] Read more.

Atmospheric oxygen is produced and consumed by life on Earth, and the ozone layer protects life on Earth from harmful solar UV radiation. The research on oxygen in the Earth system is of interest to many different geoscientific communities, from paleoclimatology to aeronomy. I provide a brief overview of the research activities and their motivations. In situ measurements and remote sensing of atmospheric oxygen are described. The global evolution, distribution, and trends of atmospheric oxygen are discussed. Full article

(This article belongs to the Special Issue Feature Papers in Oxygen Volume Ⅱ)

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