Non-enzymatic Mechanisms Research Articles

Early Antioxidative Response to Desiccant-Stimulated Drought Stress in Field-Grown Traditional Wheat Varieties

Extended drought affects the production and quality of wheat (Triticum aestivum L.), one of the world's most important food crops. Breeding for increased drought resistance is becoming increasingly important due to the rising demand for food production. Four old traditional Croatian wheat cultivars were used in the present study to examine the early antioxidant response of flag leaves to desiccant-stimulated drought stress and to identify drought-tolerant cultivars accordingly. The results indicate that the enzymatic antioxidant system plays the most significant role in the early response of adult wheat plants to drought stress and the removal of excessive H2O2, particularly GPOD and APX. Nada and Dubrava cultivars revealed the strongest activation of the enzymatic defense mechanism, which prevented H2O2 accumulation and lipid peroxidation. Additionally, the Nada cultivar also showed increased synthesis of proline and specific phenolic compounds, which both contribute to the increased stress tolerance. Among the cultivars investigated, cultivar Nada has the broadest genetic base, which may explain why it possesses the ability to activate both enzymatic and non-enzymatic defense mechanisms in an early response to drought stress. This suggests that old traditional wheat cultivars with broad genetic bases can be a valuable source of drought tolerance, which is especially important given the current climate change.

Platelet aggregation inhibitors from Bothrops alternatus snake venom

Snake venoms are a complex mixture of proteins and peptides that can activate/inhibit platelet aggregation. Bothrops alternatus venom include three main families: metalloproteinases (SVMPs), serinoproteinases (SVSPs) and phospholipases A2 (PLA2s), among other minor components. In this work, we used inhibitor cocktails (containing Na2-EDTA, PMSF and/or pBPB) to investigate the effect of these three families and of baltergin (a PIII SVMP) on platelet aggregation by a turbidmetric method using a microplate reader. Cocktails 1 (active SVMPs) and 2 (active PLA2s) significantly reduced aggregation induced by ristocetin and collagen and by collagen and thrombin, respectively. Cocktail 3 (active SVSPs) showed a mild activation of aggregation, indicating the content of thrombin-like enzymes (TLEs) in this venom is low. Cocktail 4 (active minor components) displayed inhibitory effect with all agonists assayed (ristocetin, ADP, collagen and thrombin) but at higher IC50 values. Baltergin exhibited inhibitory effect when the catalytic domain was active for ristocetin-stimulated platelet aggregation and showed a non-enzymatic mechanism of inhibition when collagen was used as agonist. It was not able to disaggregate platelet thrombus. We conclude that B. alternatus venom is a source of natural inhibitors of platelet aggregation due to the action of SVMPs and PLA2s. Other minor components such as C-type lectins likely contribute to the antiplatelet effect. The interest in knowing the action of venom components on platelet function lies both in the understanding of the pathophysiology of snake bite envenomation and in their biotechnological application.

Particle films improve photosynthesis of citrus trees under excess irradiance by reducing leaf temperature

High irradiance and increased air temperature during extreme weather conditions affect tree crops and impact the yield and quality of fruits. Moreover, flowering and fruit set of Citrus are likely impaired by UV radiation and/or reduced carbon assimilation, which increase reactive oxygen species production and damage the leaf photosynthetic apparatus. Particle coating films sprayed on leaves have been offered as a way to minimize crop losses due to the climate change scenario, even though the extent of leaf protection is not characterized. We evaluated the use of two protective films on the oxidative stress and leaf photosynthesis of sweet orange trees exposed to varying daylight levels. Trees were maintained under full sun light, sprayed or not (control) with kaolin or calcium carbonate, and under reduced irradiance using either aluminum shade cloth 50% or anti-UV transparent plastic. Kaolin or calcium carbonate reflected 20%-30% of the incident light on the leaf surface compared to leaves not sprayed and under full sunlight. Leaves with coating exhibited improved CO2 assimilation and photosystem II efficiency, and lower leaf temperatures over time. In addition, the coating protected leaves against excess irradiance due to dissipation of excess energy into the photosynthetic apparatus (NPQt). Nonenzymatic mechanisms for UV protection, such as carotenoids, were higher in full sun control plants than in leaf-coated plants. Comparable responses were observed on trees maintained covered either by the cloth or the plastic film. Finally, we conclude that the use of suspension particles mitigates the harmful effects of excess UV irradiance and temperature in sweet orange trees.

Antioxidant response of Impatiens walleriana L. to drought

Stress caused by drought induces plant morphology, biochemistry, and physiology changes, leading to considerable reductions in plant growth and productivity. This study aimed to evaluate the antioxidant defence system of impatiens seedlings (Impatiens walleriana L.) under drought. The antioxidant response of impatiens to drought was evaluated using following parameters: the activity of catalase, guaiacol peroxidase, pyrogallol peroxidase and ascorbate peroxidase, total phenolic and flavonoids contents and total antioxidant capacity. The experiment was conducted during 2020 in a greenhouse under controlled conditions. Half of the impatiens seedlings (20 plants), after the acclimation period in the greenhouse, were exposed to drought for a period of five days, while the second half was not (20 plants were regularly watered). The results of the study showed that the exposure of impatiens seedlings to drought increased the activity of enzymatic components, total phenolics and flavonoids contents and total antioxidant capacity of leaves. Greater exposure of impatiens to drought (in the observed period) implied a higher plant enzymatic and non-enzymatic antioxidant defence system activity. These results confirm that impatiens has evolved both enzymatic and non-enzymatic antioxidant defence mechanisms to adapt and survive the short-term drought exposure.

Quinone-mediated non-enzymatic browning in model systems during long-term storage.

Non-enzymatic browning induced by polyphenol oxidation is an essential problem during the processing and storage of fruit and vegetable products. Here, the non-enzymatic browning mechanism between catechin (CAT), chlorogenic acid (CQA) and their corresponding quinones was investigated in model systems during the 32-d long-term storage. The results showed that CAT and catechin quinone (CATQ), which contains both A ring with a resorcinol structure and an o-diphenol B ring, are important precursors for browning, while chlorogenic acid (CQA) has a minor effect on browning. Chlorogenic acid quinone (CQAQ)-mediated CAT oxidation (kCAT-degradation=0.0458mol·L-1·d-1) was faster than CAT autoxidation (kCAT-degradation=0.0006mol·L-1·d-1), and there was no significant difference between CQAQ-mediated CAT oxidation and CATQ-mediated CQA oxidation. These indicate that CQAQ oxidizes CAT to CATQ quickly, and CATQ reacts with CAT subsequently through complex reactions to produce brown pigments in model systems during long-term storage.

Non-Enzymatic Antioxidants in Stressed Plants: A Review

Plants are exposed to different ecological stress during their life cycle, and because of these tensions, free radicals are shaped. Reactive oxygen species(ROS) have a fundamental ability to support typical plant improvement and stress tolerance. The disruption of the proportionality of ROS generation and antioxidant defense systems is one of the primary effects of biotic and abiotic stress, resulting in an excess of ROS buildup and oxidative damage in plants. Plants may combat this issue by producing ROS-neutralizing compounds, and both enzymatic and non-enzymatic antioxidant defense mechanisms maintain the proper ratio between ROS generation and detoxification. Ascorbic acid (AsA), glutathione (GSH), flavonoids, Vitamin E (α-tocopherols), and carotenoids are crucial non-enzymatic antioxidants in this context, with a high potential for performing a variety of crucial activities in plants under both stressful and unstressful conditions, in addition to scavenging ROS. This review illustrates the main roles of some non-enzymatic antioxidants in plants subjected to various types of biotic and abiotic stresses.

Analysis of the Antioxidant Mechanism of Tamarix ramosissima Roots under NaCl Stress Based on Physiology, Transcriptomic and Metabolomic.

There is a serious problem with soil salinization that affects the growth and development of plants. Tamarix ramosissima Ledeb (T. ramosissima), as a halophyte, is widely used for afforestation in salinized soils. At present, there are few reports on the antioxidant mechanism of T. ramosissima under NaCl stress. In this study, we learned about the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) content changes in T. ramosissima. We also mined the relevant metabolic pathways in the antioxidant mechanism, candidate key genes, and their related differential metabolites and verified them using quantitative real-time PCR (qRT-PCR). The results show that the SOD, POD, and CAT activities, and the H2O2 and MDA content reached the highest values in the roots of T. ramosissima. Simultaneously, 92 differentially expressed genes (DEGs) related to antioxidant enzyme activities changed during 48 and 168 h of NaCl stress, and these DEGs were mainly upregulated in 168 h. Based on the association analysis of transcriptomic and metabolomic data, we found Unigene0089358 and Unigene0007782 as genes related to key enzymes in the flavonoid biosynthesis pathway. They were located in the upstream positive regulation at 48 and 168 h under NaCl stress, and their respective related metabolites (phloretin and pinocembrin) were involved in resistance to NaCl stress, and they were significantly correlated with their respective metabolites. In conclusion, at 48 and 168 h under NaCl stress, the roots of T. ramosissima resist NaCl stress by enhancing enzymatic and nonenzymatic antioxidant mechanisms, scavenging ROS generated by high-salt stress, alleviating NaCl toxicity, and maintaining the growth of T. ramosissima. This study provides genetic resources and a scientific theoretical basis for further breeding of salt-tolerant Tamarix plants and the molecular mechanism of antioxidants to alleviate NaCl toxicity.

Antioxidant Supplementation in Oxidative Stress-Related Diseases: What Have We Learned from Studies on Alpha-Tocopherol?

Oxidative stress has been proposed as a key contributor to lifestyle- and age-related diseases. Because free radicals play an important role in various processes such as immune responses and cellular signaling, the body possesses an arsenal of different enzymatic and non-enzymatic antioxidant defense mechanisms. Oxidative stress is, among others, the result of an imbalance between the production of various reactive oxygen species (ROS) and antioxidant defense mechanisms including vitamin E (α-tocopherol) as a non-enzymatic antioxidant. Dietary vitamins, such as vitamin C and E, can also be taken in as supplements. It has been postulated that increasing antioxidant levels through supplementation may delay and/or ameliorate outcomes of lifestyle- and age-related diseases that have been linked to oxidative stress. Although supported by many animal experiments and observational studies, randomized clinical trials in humans have failed to demonstrate any clinical benefit from antioxidant supplementation. Nevertheless, possible explanations for this discrepancy remain underreported. This review aims to provide an overview of recent developments and novel research techniques used to clarify the existing controversy on the benefits of antioxidant supplementation in health and disease, focusing on α-tocopherol as antioxidant. Based on the currently available literature, we propose that examining the difference between antioxidant activity and capacity, by considering the catabolism of antioxidants, will provide crucial knowledge on the preventative and therapeutical use of antioxidant supplementation in oxidative stress-related diseases.

Towards pharmaceutical protein stabilization: DFT and statistical learning studies on non-enzymatic peptide hydrolysis degradation mechanisms

Theoretical studies on amide hydrolysis are of interest due to their impact on the drug discovery and delivery sectors of the biopharmaceutical industry. For degradation in which biopharmaceuticals and biopolymers may degrade through multiple different mechanisms, reaction families are established through the proposed mechanisms. Due to the influence of non-bonded interactions upon reactivity, the electrostatic interactions between the biopolymer and its environment must also be quantified to obtain a robust understanding of the system. For this purpose, we conducted a study of representative model dipeptides to analyze the reaction paths of non-enzymatic amide hydrolysis to generate a self-consistent database of thermochemical and kinetic values over a range of dielectrics using Density Functional Theory and statistical thermodynamics, and was found to capture experimental trends. Additionally, our study generated statistically significant linear correlations to predict the activation energy of the gemdiol formation step of the stepwise mechanism for the overall data set, as well as a function of the modeled dielectric.

Functional Modulation of Human Macrophages by Secreted Phospholipases A2: Implications in Cancer.

Cancer-related inflammation has recently emerged as an important component of cancer pathogenesis that is able to promote tumor initiation and progression, and the acquisition of the known hallmark capabilities, including evasion from immunosurveillance. Several soluble and cellular mediators participate in tumor microenvironment formation, leading to cancer initiation and progression. In this view, Tumor-Associated Macrophages (TAMs) are pivotal players and, due to their characteristic plasticity, can acquire a variety of distinct phenotypes and contribute in different ways to the different phases of carcinogenesis. Different stimuli have been shown to modulate macrophage polarization. Secreted phospholipase A2 enzymes (sPLA2s) exert multiple biological effects on cancer-related inflammation due to their enzymatic activity and ability to activate inflammatory cells by non-enzymatic mechanisms. Among the different sPLA2 isoforms, several studies have suggested that group IIA and group X are mainly involved in a wide variety of cancer types. A deeper insight into the molecular mechanisms regulating the link between tumor-infiltrating immune cells and cancer could lead to identifying new prognostic/predictive biomarkers and a broader view of cancer immunotherapy.

Halotolerant Streptomyces spp. induce salt tolerance in maize through systemic induction of the antioxidant system and accumulation of proline

Plant Growth Promoting Rhizobacteria (PGPR) can mitigate the detrimental effects of salinity in plants. We characterized Streptomyces spp. as halotolerant PGPR and evaluated their influence on salt stress-tolerance mechanisms in maize plants. Bacterial halotolerance was evaluated at concentrations up to 900 mM NaCl, analyzing cell growth, viability, and production of secondary metabolites. The mechanisms of systemic tolerance in plants, such as the enzymatic activity of the antioxidant system and the production of osmolytes, were analyzed in bacterized plants under salt stress (100 and 300 mM NaCl). Isolates proved viable and produced indolic compounds and siderophores under NaCl conditions. Synthesis of indolic compounds and phosphate solubilization were induced in CLV179 by salt stress. The activity of the antioxidant enzymes and the synthesis of proline increased in bacterized plants submitted to salt stress, mainly those treated with isolate CLV97 and CLV179. Response of Streptomyces-treated plant to salinity was observed in roots and leaves, suggesting a mechanism of systemic tolerance. Therefore, bacterization with Streptomyces spp. alleviated the deleterious effects of salinity in maize plants by modulating the enzymatic and non-enzymatic antioxidant mechanisms.

Cellulose microfluidic pH boosting on copper oxide non-enzymatic glucose sensor strip for neutral pH samples

A cellulose microfluidic pH boosting layer adapts a non-enzymatic copper oxide glucose sensor strip for neutral pH samples. This adaptation allows the non-enzymatic technology to realize in-situ glucose measurements. A three-electrode system is constructed to test samples in a classical electrochemical cell, and in a sensing strip to test the microfluidic system. The system consists of copper oxide as working electrode, and silver and carbon paints as reference, and counter electrodes, respectively. The fabrication of the pH-boosting layer is made with natural cellulose. Within this layer are NaOH crystals, grown by a drying processes after immersion of cellulose in a concentrated solution of NaOH. The microfluidic layer is placed on top of the sensing electrodes, and while it transports the fluid sample to the sensing electrodes, the fluid dissolves the NaOH crystals, increasing the pH of the sample. This change allows the non-enzymatic mechanism to sense the glucose concentration in the fluid. Our system shows the capability to measure glucose in samples with neutral pH and human blood with a sensitivity of 70 μA/mM cm2, enough to distinguish between hypoglycemia and hyperglycemia.

Biotic elicitor-induced changes in growth, antioxidative defense, and metabolites in an improved prickleless Solanum viarum.

Solanum viarum serves as a raw material for the steroidal drug industry due to its alkaloid and glycoalkaloid content. Elicitation is well-known for measuring the increase in the yield of bioactive compounds in in vitro cultures. The current study was performed for the accumulation of metabolites viz. solasodine, solanidine, and α-solanine in S. viarum culture using microbial-based elicitors added in 1%, 3%, 5%, and 7% on 25th and 35th day of culture period and harvested on 45th and 50th days of culture cycle. The treatment of 3% Trichoderma reesei and Bacillus tequilensis culture filtrate (CF) significantly increased biomass, alkaloids/glycoalkaloid content, and yield in S. viarum. T. reesei was found to be the best treatment for enhanced growth (GI = 11.65) and glycoalkaloid yield (2.54mg DW plant-1) after the 50th day of the culture cycle when added on the 25th day. The abundance of gene transcripts involved in the biosynthesis of alkaloids/glycoalkaloids, revealed by quantitative real-time PCR expression analysis correlates with the accumulation of their respective metabolites in elicited plants. Biochemical analysis shows that elicited plants inhibited oxidative damage caused by reactive oxygen species by activating enzymes (superoxide dismutase and ascorbate peroxidase) as well as non-enzymatic antioxidant mechanisms (alkaloids, total phenols, total flavonoids, carotenoids, and proline). The findings of this study clearly demonstrate that the application of T. reesei and B. tequilensis CF at a specific dose and time significantly improve biomass as well as upregulates the metabolite biosynthetic pathway in an important medicinal plant- S. viarum. KEY POINTS: • Biotic elicitors stimulated the alkaloids/glycoalkaloid content in S. viarum plant cultures. • T. reesei was found to be most efficient for enhancing the growth and alkaloids content. • Elicited plants activate ROS based-defense mechanism to overcome oxidative damage.

Lysine acetylation decreases enzyme activity and protein level of Escherichia coli lactate dehydrogenase

Lactate is an important bulk chemical with widespread applications and a major byproduct of other chemicals bioprocess in microbial fermentation. Lactate dehydrogenase A (LdhA) catalyzes the synthesis of lactate from pyruvate. Lysine acetylation is an evolutionarily conserved post-translational modification; however, the mechanisms underlying the regulation of LdhA function by lysine acetylation in Escherichia coli remain poorly understood. Herein, we demonstrate acetylation of E. coli LdhA occurs via enzymatic and non-enzymatic mechanisms. Further, we show carbon source type and concentration affect the lysine acetylation status of LdhA via a non-enzymatic mechanism. Lysine acetylation significantly inhibits the enzymatic activity and protein level of LdhA. The results of the present study demonstrate lysine acetylation of E. coli LdhA is irreversible. Understanding of the effects of lysine acetylation on LdhA function may provide a new perspective for regulating lactate production in microbial synthesis.

Nonenzymatic Reactions in Natural Product Formation.

Biosynthetic mechanisms of natural products primarily depend on systems of protein catalysts. However, within the field of biosynthesis, there are cases in which the inherent chemical reactivity of metabolic intermediates and substrates evades the involvement of enzymes. These reactions are difficult to characterize based on their reactivity and occlusion within the milieu of the cellular environment. As we continue to build a strong foundation for how microbes and higher organisms produce natural products, therein lies a need for understanding how protein independent or nonenzymatic biosynthetic steps can occur. We have classified such reactions into four categories: intramolecular, multicomponent, tailoring, and light-induced reactions. Intramolecular reactions is one of the most well studied in the context of biomimetic synthesis, consisting of cyclizations and cycloadditions due to the innate reactivity of the intermediates. There are two subclasses that make up multicomponent reactions, one being homologous multicomponent reactions which results in dimeric and pseudodimeric natural products, and the other being heterologous multicomponent reactions, where two or more precursors from independent biosynthetic pathways undergo a variety of reactions to produce the mature natural product. The third type of reaction discussed are tailoring reactions, where postmodifications occur on the natural products after the biosynthetic machinery is completed. The last category consists of light-induced reactions involving ecologically relevant UV light rather than high intensity UV irradiation that is traditionally used in synthetic chemistry. This review will cover recent nonenzymatic biosynthetic mechanisms and include sources for those reviewed previously.

The Effect of β-Carotene, Tocopherols and Ascorbic Acid as Anti-Oxidant Molecules on Human and Animal In Vitro/In Vivo Studies: A Review of Research Design and Analytical Techniques Used.

Prolonged elevated oxidative stress (OS) possesses negative effect on cell structure and functioning, and is associated with the development of numerous disorders. Naturally occurred anti-oxidant compounds reduce the oxidative stress in living organisms. In this review, antioxidant properties of β-carotene, tocopherols and ascorbic acid are presented based on in vitro, in vivo and populational studies. Firstly, environmental factors contributing to the OS occurrence and intracellular sources of Reactive Oxygen Species (ROS) generation, as well as ROS-mediated cellular structure degradation, are introduced. Secondly, enzymatic and non-enzymatic mechanism of anti-oxidant defence against OS development, is presented. Furthermore, ROS-preventing mechanisms and effectiveness of β-carotene, tocopherols and ascorbic acid as anti-oxidants are summarized, based on studies where different ROS-generating (oxidizing) agents are used. Oxidative stress biomarkers, as indicators on OS level and prevention by anti-oxidant supplementation, are presented with a focus on the methods (spectrophotometric, fluorometric, chromatographic, immuno-enzymatic) of their detection. Finally, the application of Raman spectroscopy and imaging as a tool for monitoring the effect of anti-oxidant (β-carotene, ascorbic acid) on cell structure and metabolism, is proposed. Literature data gathered suggest that β-carotene, tocopherols and ascorbic acid possess potential to mitigate oxidative stress in various biological systems. Moreover, Raman spectroscopy and imaging can be a valuable technique to study the effect of oxidative stress and anti-oxidant molecules in cell studies.

Salicyclic acid against the disruptive effects of cadmium induces oxidative stress and ‎biochemical and histopathological changes in the ovary of the freshwater leech Limnatis ‎nilotica (Savigny, 1822)‎

ABSTRACT In this study, we investigated the effect of Cd on the ovaries of the freshwater leech Limnatis nilotica and the ability of salicylic acid (SA) treatment to alleviate the Cd harmful effects. Our results showed that Cd treatment increased the level of oxidative stress leading to severe alterations in histopathological and biochemical indexes. Cd exposure was found to induce a substantial increase in malondialdehyde (MDA) and hydrogen peroxidase (H2O2) contents as well as an impairment in catalase (CAT) and Glutathione peroxidase (GPx) activities. These findings are thoroughly supported by histopathological evidence which showed several modifications in the ovary cord organization. However, SA addition reduced the toxic effect of Cd-exposure through decreasing MDA and H2O2 levels, the regulation of enzymatic and nonenzymatic antioxidant mechanism pathways leading to the alleviation of the histopathological lesions. These results suggest that SA can prevent damage under Cd toxicity in the leech ovaries.

Investigations on the Fusants From Wide Cross Between White-Rot Fungi and Saccharomyces cerevisiae Reveal Unknown Lignin Degradation Mechanism.

The degradation of lignocellulose by fungi, especially white-rot fungi, contributes a lot to carbon cycle, bio-fuel production, and many other bio-based applications. However, the existing enzymatic and non-enzymatic degradation mechanisms cannot be unequivocally supported by in vitro simulation experiment, meaning that additional mechanisms might exist. Right now, it is still very difficult to discover new mechanisms with traditional forward genetic approaches. To disclose novel lignin degradation mechanisms in white-rot fungi, a series of fusants from wide cross by protoplast fusion between Pleurotus ostreatus, a well-known lignin-degrading fungus, and Saccharomyces cerevisiae, a well-known model organism unable to degrade lignocellulose, was investigated regarding their abilities to degrade lignin. By analyzing the activity of traditional lignin-degrading enzyme, the ability to utilize pure lignin compounds and degrade corn stalk, a fusant D1-P was screened out and proved not to contain well-recognized lignin-degrading enzyme genes by whole-genome sequencing. Further investigation with two-dimension nuclear magnetic resonance (NMR) shows that D1-P was found to be able to degrade the main lignin structure β-O-4 linkage, leading to reduced level of this structure like that of the wild-type strain P. ostreatus after a 30-day semi-solid fermentation. It was also found that D1-P shows a degradation preference to β-O-4 linkage in Aβ(S)-threo. Therefore, wide cross between white-rot fungi and S. cerevisiae provides a powerful tool to uncover novel lignocellulose degradation mechanism that will contribute to green utilization of lignocellulose to produce bio-fuel and related bio-based refinery.

A Brief Review on Evaluation and Exploration of Antioxidant Activity of Mango Ginger

Many free radicals are generates in the human body due to metabolic processes and in order to counteract the harmful effects of these antioxidants, human body has a complex system of natural enzymatic and non-enzymatic antioxidant defenses or mechanisms. These free radicals are mainly responsible for generation of different types of diseases and disorders. Hence protection of body against free radical is important and which can also be done by taking diet with maximum antioxidants. Naturally occurring antioxidant are very important in preventing body from various free radicals. Many medicinal plants and their extracts have been reported for potential anti-oxidant activity. Curcuma amada Roxb (Mango Ginger) is the most important genera come under the Zingiberaceae family. Chemically it has reported for the presence of wide range of phytoconstituents which include the flavonoids, terpenoids, tannins steroids, alkaloids, glycosides and essential oils. Due to presence of wide variety of phytoconstituents plant has very well traditional value reported for pharmacological significance for a variety of ailments. It effectively treats skin allergies, stomach problems, and high blood cholesterol and has been reported for antioxidant properties. In the present review work various research articles published on antioxidant activity of Mango Ginger Have been collected from various journal site and databases and explored systematically

Development of a Non-Enzymatic Glucose Sensor Based on Fe2O3 Nanoparticles-Carbon Paste Electrodes

Fe2O3 nanoparticles have interesting properties such as low production cost, chemical stability, biocompatibility, poor toxicity and high conductivity. In this work, Fe2O3 nanoparticles are used as modifiers to combine its characteristics to those of carbon paste electrodes to enhance the determination of glucose. Differential pulse voltammetry was used as the quantitative analytical technique and then, a Box-Behnken design was used to optimize the its variables in order to maximize the glucose electro-oxidation response signal. The Fe2O3-NPs/CPE sensor showed excellent electro-catalytic performance towards glucose oxidation and three linear ranges: 0.015 μM–1 μM (sensitivity of 51.54 μA/ μM), 1 μM–100 μM (sensitivity of 4.21 μA/μM) and, 30 μM–700 μM (sensitivity of 0.041 μA μM−1) and detection limit of 0.044 μM. The sensor also presented good reproducibility and repeatability, excellent selectivity (in the presence of ascorbic acid, uric acid, lactose, caffeine, and paracetamol), and satisfactory applicability for glucose detection in commercial electrolyte beverages and human urine samples. The improved electrochemical detection capability of Fe2O3-NPs/CPE is attributed to the formation of Fe4+ = O reactive groups at alkaline pH that allowed the oxidization of glucose by a nonenzymatic mechanism.