Browsing by Subject "ASCORBIC-ACID"

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  • Raudsepp, Piret; Koskar, Julia; Anton, Dea; Meremäe, Kadrin; Kapp, Karmen; Laurson, Peeter; Bleive, Uko; Kaldmäe, Hedi; Roasto, Mati; Püssa, Tõnu (2019)
    BACKGROUND It is important to find plant materials that can inhibit the growth of Listeria monocytogenes and other food-spoiling bacteria both in vitro and in situ. The aim of the study was to compare antibacterial and antioxidative activity of selected plant-ethanol infusions: leaves and berries of blackcurrant (Ribes nigrum L.), berries of chokeberry (Aronia melanocarpa (Michx.) Elliott) and blue honeysuckle (Lonicera caerulea L. var. edulis); petioles and dark and light roots of garden rhubarb (Rheum rhaponticum L.) for potential use in food matrices as antibacterial and antioxidative additives. RESULTS The strongest bacterial growth inhibition was observed in 96% ethanol infusions of the dark roots of rhubarbs. In 96% ethanol, nine out of ten studied plant infusions had antibacterial effect against L. monocytogenes, but in 20% ethanol only the infusions of dark rhubarb roots had a similar effect. Chokeberry and other berries had the highest antioxidative activity, both in 20% and 96% ethanol infusions. CONCLUSION The combination of dark rhubarb roots or petioles and berries of black chokeberry, blackcurrant or some other anthocyanin-rich berries would have potential as both antibacterial and antioxidative additives in food. (c) 2018 Society of Chemical Industry
  • Hemilä, Harri (2005)
    In their paper discussing the assessment of blinding in clinical trials, Bang et al. based their analysis on the premise that "all participants randomly guess their assignment... This is the most ideal scenario in reality". However, this premise makes an implicit assumption that the drug does not differ from placebo in any physiological effects that a person could observe subjectively, which is a very strong assumption. If a drug is truly effective, such as penicillin for pneumococcal pneumonia, both the patient and the physician can infer the treatment with high certainty by subjective observations. Thus, when the drug is truly effective, we are expecting "breaking of blindness".
  • Hemilä, Harri (2008)
    In their paper discussing the importance of double-blinding in controlled trials, Furberg and Soliman stated that one of the established and fundamental principles for avoiding the problem of bias is to keep the study participants and the investigators blinded, or masked, to the identity of the assigned interventions. As a support to this argument they described the subgroup findings of Karlowski et al.s trial, which examined the effect of vitamin C supplementation on the commoncold[2,3]. Furberg and Soliman put a great weight on the importance of double-blinding, yet they are lax on other fundamental principles of controlled trial.
  • Rehman, Sidra; Mansoora, Nida; Al-Dhumri, Sami A.; Amjad, Syeda F.; Al-Shammari, Wasimah B.; Almutari, Mohammad M.; Alhusayni, Fatimah S.; Al Bakre, Dhafer A.; Lalarukh, Irfana; Alshahri, Abdullah H.; Poczai, Peter; Galal, Tarek M.; Abdelhafez, Ahmed A. (2022)
    Heavy metal stress and less nutrient availability are some of the major concerns in agriculture. Both abiotic stresses have potential to decrease the crops productivity. On the other hand, organic fertilizers i.e., activated carbon biochar (ACB) and arbuscular mycorrhizal fungi (AMF) increase nutritional and heavy metal like Nickel (Ni) stress tolerance and provide immunity to plants for their survival in unfavorable environments. Previous studies have only looked at single applications of either ACB or AMF thus far. There is limited evidence of their synergistic effects, especially in plants growing in soil contaminated with nickel (Ni). To cover the knowledge gap of combined use of AMF inoculation (Glomus intraradices) and/or wheat straw biochar amendments on wheat growth, antioxidant activities and osmolytes concentration, present study is conducted. The use of either the AMF inoculant or the ACB alone resulted in improved wheat growth and decreased Ni uptake. Furthermore, sole AMF or ACB also reduced Ni stress effectively, allowing wheat to grow faster and reducing soil Ni transfer into plant tissue. In comparison to a control, adding ACB with AMF inoculant considerably increased fungal populations. The most significant increase in wheat growth and decrease in tissue Ni contents came from amending soil with AMF inoculant and biochar. Inducing soil alkalinization and causing Ni immobilization, as well as decreasing Ni phyto-availability, the combination treatment had a synergistic impact. These findings imply that AMF inoculation in ACB treatment could be used not only for wheat production but also for Ni-contaminated soil phyto-stabilization. (C) 2022 The Author(s). Published by Elsevier B.V.
  • Hemilä, Harri; Chalker, Elizabeth (2022)
    Evidence has shown unambiguously that, in certain contexts, vitamin C is effective against the common cold. However, in mainstream medicine, the views on vitamin C and infections have been determined by eminence-based medicine rather than evidence-based medicine. The rejection of the demonstrated benefits of vitamin C is largely explained by three papers published in 1975-two published in JAMA and one in the American Journal of Medicine-all of which have been standard citations in textbooks of medicine and nutrition and in nutritional recommendations. Two of the papers were authored by Thomas Chalmers, an influential expert in clinical trials, and the third was authored by Paul Meier, a famous medical statistician. In this paper, we summarize several flaws in the three papers. In addition, we describe problems with two recent randomized trial reports published in JAMA which were presented in a way that misled readers. We also discuss shortcomings in three recent JAMA editorials on vitamin C. While most of our examples are from JAMA, it is not the only journal with apparent bias against vitamin C, but it illustrates the general views in mainstream medicine. We also consider potential explanations for the widespread bias against vitamin C.
  • Hemilä, Harri; Chalker, Elizabeth (2021)
    A Commentary on: The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19. A review of the effects of vitamin C on the immune system and respiratory tract infections was recently published (1). We are the authors of a review of vitamin C and the common cold (2), which was cited in the article. We consider that some of the authors’ statements are inaccurate and here we describe the issues on which we disagree.
  • Mäkelä, Noora; Maina, Ndegwa H.; Vikgren, Päivi; Sontag-Strohm, Tuula (2017)
    Viscosity of cereal beta-glucan during digestion is considered to be a vital factor for its health effects. Thus, studies on solution properties and gelation are essential for understanding the mechanisms of the beta-glucan functionality. The aim of this study was to investigate the effect of the dissolution temperature on gelation of cereal beta-glucan at low concentrations that are relevant for food products. The rheological properties of oat and barley beta-glucans (OBG and BBG) using three dissolution temperatures (37 degrees C, 57 degrees C and 85 degrees C) at low concentration (1.5% and 1%, respectively) were studied for 7 days. Additionally, the beta-glucans were oxidised with 70 mM H2O2 and 1 mM FeSO4 x 7H(2)O as a catalyst, to evaluate the consequence of oxidative degradation on the gelation properties. The study showed that dissolution at 85 degrees C did not result in gelation. The optimal dissolution temperature for gelation of OBG was 37 degrees C and for gelation of BBG 57 degrees C. At these temperatures, also the oxidised OBG and BBG gelled, although the gel strength was somewhat lower than in the non-oxidised ones. Gelation was suggested to require partial dissolution of beta-glucan, which depended on the molar mass and aggregation state of the beta-glucan molecule. Therefore, the state of beta-glucan in solution and its thermal treatment history may affect its technological and physiological functionality. (C) 2017 Elsevier Ltd. All rights reserved.
  • Lalarukh, Irfana; Amjad, Syeda F.; Mansoora, Nida; Al-Dhumri, Sami A.; Alshahri, Abdullah H.; Almutari, Mohammad M.; Alhusayni, Fatimah S.; Al-Shammari, Wasimah B.; Poczai, Peter; Abbas, Mohamed H. H.; Elghareeb, Doaa; Kubra, Khadija Tul; Abdelhafez, Ahmed A. (2022)
    Drought stress is among the major threats that affect negatively crop productivity in arid and semi-arid regions. Probably, application of some additives such as biochar and/or brassinosteroids could mitigate this stress; however, the mechanism beyond the interaction of these two applications is not well inspected. Accordingly, a greenhouse experiment was conducted on wheat (a strategic crop) grown under deficit irrigation levels (factor A) i.e., 35% of the water holding capacity (WHC) versus 75% of WHC for 35 days while considering the following additives, i.e., (1) biochar [BC, factor B, 0, 2%] and (2) the foliar application of 24-epibrassinolide [BR, factor C, 0 (control treatment, C), 1 (BR1) or 3 (BR2) mu mol)]. All treatments were replicated trice and the obtained results were statistically analyzed via the analyses of variance. Also, heat-map conceits between measured variables were calculated using the Python software. Key results indicate that drought stress led to significant reductions in all studied vegetative growth parameters (root and shoot biomasses) and photosynthetic pigments (chlorophyll a, b and total contents) while raised the levels of oxidative stress indicators. However, with the application of BC and/or BR, significance increases occurred in the growth attributes of wheat plants, its photosynthetic pigments, especially the combined additions. They also upraised the levels of enzymatic and non-enzymatic antioxidants while decreased stress indicators. Furthermore, they increased calcium (Ca), phosphorus (P) and potassium (K) content within plants. It can therefore be deduced that the integral application of BR and BC is essential to mitigate drought stress in plants.
  • Hemilä, Harri (2011)
    Lykkesfeldt and Poulsen's review has a promising title, and in the introductory paragraph, they state that ‘over the years, it has been suggested that vitamin C be used as a remedy against many diseases as different as common colds and cancers’(1). Given their title and introduction, one would expect a discussion about randomised controlled trials (RCT) on vitamin C and the common cold. However, this topic is ignored in their review. This is an unfortunate omission because the common cold studies give interesting information on the issues that Lykkesfeldt and Poulsen discuss.
  • Mäkelä, Noora; Sontag-Strohm, Tuula; Schiehser, Sonja; Potthast, Antje; Maaheimo, Hannu; Maina, Ndegwa H. (2017)
    Oxidation of cereal beta-glucans may affect their stability in food products. Generally, polysaccharides oxidise via different pathways leading to chain cleavage or formation of oxidised groups within the polymer chain. In this study, oxidation pathways of oat and barley beta-glucans were assessed with different concentrations of hydrogen peroxide (H2O2) or ascorbic acid (Asc) with ferrous iron (Fe2+) as a catalyst. Degradation of beta-glucans was evaluated using high performance size exclusion chromatography and formation of carbonyl groups using carbazole-9-carbonyloxyamine labelling. Furthermore, oxidative degradation of glucosyl residues was studied. Based on the results, the oxidation with Asc mainly resulted in glycosidic bond cleavage. With H2O2, both glycosidic bond cleavage and formation of carbonyl groups within the beta-glucan chain was found. Moreover, H2O2 oxidation led to production of formic acid, which was proposed to result from Ruff degradation where oxidised glucose (gluconic acid) is decarboxylated to form arabinose. (C) 2016 Elsevier Ltd. All rights reserved.
  • Marciani, L.; Garsed, K. C.; Hoad, C. L.; Fields, A.; Fordham, I.; Pritchard, S. E.; Placidi, E.; Murray, K.; Chaddock, G.; Costigan, C.; Lam, C.; Jalanka-Tuovinen, J.; De Vos, W. M.; Gowland, P. A.; Spiller, R. C. (2014)
  • Hemila, Harri (2014)
    Physical activity increases oxidative stress and therefore the antioxidant effects of vitamin C administration might become evident in people undertaking vigorous exercise. Vitamin C is involved in the metabolism of histamine, prostaglandins, and cysteinyl leukotrienes, all of which appear to be mediators in the pathogenesis of exercise-induced bronchoconstriction (EIB). Three studies assessing the effect of vitamin C on patients with EIB were subjected to a meta-analysis and revealed that vitamin C reduced postexercise FEV1 decline by 48% (95% CI: 33% to 64%). The correlation between postexercise FEV1 decline and respiratory symptoms associated with exercise is poor, yet symptoms are the most relevant to patients. Five other studies examined subjects who were under short-term, heavy physical stress and revealed that vitamin C reduced the incidence of respiratory symptoms by 52% (95% CI: 36% to 65%). Another trial reported that vitamin C halved the duration of the respiratory symptoms in male adolescent competitive swimmers. Although FEV1 is the standard outcome for assessing EIB, other outcomes may provide additional information. In particular, the mean postexercise decline of FEF50 is twice the decline of FEV1. Schachter and Schlesinger (1982) reported the effect of vitamin C on exercise-induced FEF60 levels in 12 patients suffering from EIB and their data are analyzed in this paper. The postexercise FEF60 decline was greater than 60% for five participants and such a dramatic decline indicates that the absolute postexercise FEF60 level becomes an important outcome in its own right. Vitamin C increased postexercise FEF60 levels by 50% to 150% in those five participants, but had no significant effect in the other seven participants. Thus, future research on the effects of vitamin C on EIB should not be restricted to measuring only FEV1. Vitamin C is inexpensive and safe, and further study on those people who have EIB or respiratory symptoms associated with exercise is warranted.
  • Mäkelä, Noora; Brinck, Outi; Sontag-Strohm, Tuula (2020)
    The physiological functionality of cereal beta-glucan (beta-glucan) has been mainly attributed to its ability to form viscous solutions in the gastrointestinal (GI) tract. The viscosity is dependent on the concentration, extractability and molecular weight of beta-glucan, and to enable maximal functionality, these factors should therefore be acknowledged and their role in the physiological functionality of cereal beta-glucan further studied. An in vitro GI simulation with separate oral, gastric and small intestine phases was used to model the state of beta-glucan from various oat products in the GI tract. A rather large variation (from 26% to 99%) was observed in the extractabilities between product categories, with the highest extractabilities observed in spoonable products. The viscosities also varied highly within categories. When the comparison was done at similar concentration levels, the highest viscosities were observed in the products produced through dry processes, and moisture content during processing was suggested to be essential to the extent of beta-glucan degradation. The viscosity in samples that were likely to exhibit enzymatic activity was shown to be rather low, and thus the physiological functionality of beta-glucan may be threatened if the product also contains grain ingredients other than kiln-dried oat. Clear differences were observed in the functionality of beta-glucan in the GI tract model depending on a product type, and these were explained by differences in ingredients and processes. However, further studies are needed to specify the influence of each factor and to clarify the factors determining the physiological functionality of beta-glucan in food products.
  • Hemilä, Harri; Douglas, R M (1999)
  • Hemila, Harri (2014)
  • Hemila, Harri; de Man, Angelique M. E. (2021)
    In numerous animal studies, vitamin C has prevented and alleviated viral and bacterial infections. In a few dozen placebo-controlled trials with humans, vitamin C has shortened infections caused by respiratory viruses, which indicates that the vitamin can also influence viral infections in humans. In critically ill patients, plasma vitamin C levels are commonly very low. Gram doses of vitamin C are needed to increase the plasma vitamin C levels of critically ill patients to the levels of ordinary healthy people. A meta-analysis of 12 trials with 1,766 patients calculated that vitamin C reduced the length of ICU stay on average by 8%. Another meta-analysis found that vitamin C shortened the duration of mechanical ventilation in ICU patients. Two randomized placebo-controlled trials found statistically significant reduction in the mortality of sepsis patients. The effects of vitamin C on acute respiratory distress syndrome (ARDS) frequently complicating COVID-19 pneumonia should be considered. Vitamin C is a safe and inexpensive essential nutrient.
  • Hemilä, Harri (2003)