Ascorbic Acid Levels Research Articles

Comparative Analysis of Morphological and Biochemical Traits in Fragaria × ananassa (Cv. Chandler) under Varied Cultivation Systems

The present research was carried out at Khalsa college Amritsar during 2018-19 to investigate the effect of different cultivation systems on the morphological and biochemical attributes of strawberry cv. Chandler under subtropical conditions of Punjab. The experiment was laid out in Randomized Block design by using eight treatments, each comprising three replications. The different planting systems including flat beds, raised beds, ridges, soilless media, polythene bags, cement pots, plastic crates and low poly tunnels were employed during this research. The runners of strawberry collected from Dr Y S Parmar University of Horticulture and Forestry, were utilized for the experiment. The morphological parameters such as fruit size, weight, number of achenes and biochemical parameters like Total soluble solids, acidity, sugars and ascorbic acid content were analyzed. The results of this present study revealed that maximum fruit length, breath, number of achenes were observed underlow poly tunnels. Similarly, the maximum TSS, total sugar content, ascorbic acid and minimum acidity level was recorded under low under poly tunnels. These outcomes strongly suggest the superiority of utilizing low poly tunnels for strawberry cultivation, emphasizing their potential to enhance both morphological traits and biochemical compositions compared to the other employed planting systems.

Supercritical Fluid Extraction of Bioactive Components from Apple Peels and Their Modulation of Complex I Activity in Isolated Mitochondria.

Supercritical fluid extraction (SFE) was used to extract bioactive compounds from apple (Malus domestica) peel waste from three different Italian cultivars. The bioactive fractions were extracted applying a temperature of 60 °C and a pressure of 250 bar for 15 min with 20% ethanol as co-solvent, at a flow rate of 2 mL/min. The total polyphenol (TP), anthocyanin (TA), ascorbic acid (AA), and antioxidant activity contents (TACs) were measured, while chromatographic analyses were performed to highlight the differences between the extracts. The Stark cultivar had the highest levels of polyphenols, anthocyanins, and ascorbic acid, while the Royal Gala cultivar showed the highest total antioxidant activity. SFE extracts were then tested for their effect on the mitochondrial NADH-ubiquinone oxidoreductase (Complex I) activity on mitochondria isolated from human embryonic kidney cells (HEK239). The Stark extract showed the most positive response in terms of NADH oxidation. The results obtained in this work highlight the potential of apple peel waste as a source of functional phytocompounds and suggest that Stark cultivar extracts may be exploited for pharmacological applications. This study supports the circular bioeconomy by promoting the use of waste products as a valuable resource.

Arginine with leucine drives reactive oxygen species-mediated integrin α5β1 expression and promotes implantation in mouse blastocysts.

The implantation rate of in vitro fertilization (IVF)-derived blastocysts after embryo transfer remains low, suggesting that the inadequate expression of specific proteins in culture-induced IVF-derived blastocysts contributes to low implantation rates. Therefore, treatment with appropriate regulation may improve the blastocyst implantation ability. This study demonstrated that the combination of l-arginine (Arg) and l-leucine (Leu) exerts distinct effects on IVF-derived mouse blastocysts. Arg with Leu promotes blastocyst implantation, whereas Arg alone decreases the blastocyst ability. Integrin α5β1 expression was increased in blastocysts treated with Arg and Leu. Arg with Leu also increased reactive oxygen species (ROS) levels and showed a positive correlation with integrin α5β1. Ascorbic acid, an antioxidant, decreased ROS and integrin α5β1 levels, which were elevated by Arg with Leu. Meanwhile, the mitochondrial membrane potential (ΔΨm) in blastocysts did not differ between treatments. Glutathione peroxidase (GPx) is involved in ROS scavenging using glutathione (GSH) as a reductant. Arg with Leu decreased GPx4 and GSH levels in blastocysts, and blastocysts with higher ROS levels had lower GPx4 and GSH levels. In contrast, Arg alone increased the percentage of caspase-positive cells, indicating that Arg alone, which attenuated implantation ability, was associated with apoptosis. This study revealed that elevated ROS levels induced by Arg with Leu stimulated integrin α5β1 expression, thereby enhancing implantation capacity. Our results also suggest that ROS were not due to increased production by oxidative phosphorylation, but rather to a reduction in ROS degradation due to diminished GPx4 and GSH levels.

Development of starch-based films reinforced with curcumin-loaded nanocomplexes: Characterization and application in the preservation of blueberries

In current study, curcumin-loaded bioactive nanocomplexes (Cur NCs) (2 %, 5 %, 8 %, and 11 %) were used to prepare corn starch (CS)-based composite films (CS-Cur NCs). Fourier-transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy revealed that Cur NCs were uniformly dispersed in the polymer matrix via physical interaction. Moreover, the mechanical, gas barrier, hydrophobicity, optical, and thermal properties and the antioxidant activity of composite films were potentially improved with the addition of Cur NCs. Subsequently, CS-based film with 11 % Cur NCs exhibited high antioxidant activity (the scavenging rates of DPPH and ABTS are 50.07 % ± 0.82 % and 65.26 % ± 1.60 %, respectively) and was used for packaging blueberries. Compared with the control, the CS-Cur NCs packaging treatment effectively improved the appearance and nutrition of blueberries, and maintained the high activity of several antioxidant enzymes. Furthermore, CS-Cur NCs packaging treatment significantly improved the ascorbic acid (AsA) and glutathione (GSH) levels, thus regulating the AsA-GSH cycle system and suppressing the accumulation of reactive oxygen species (ROS). In summary, the CS-Cur NCs packaging could effectively conserve the postharvest quality of blueberries by improving antioxidant enzyme activity and suppressing excessive accumulation of ROS, which contributes to the development of bioactive packaging and provides novel insights into the preservation of blueberries. This work demonstrates that the development of active packaging is promising to absorb the oxidative radicals from food, and protect the food from inherent and external factors, thus enhancing the quality, security, and shelf-life of the food during storage.

Determination of ascorbic acid in biological samples using an electrochemical sensor modified with Au-Cu2O/MWCNTs nanocomposite

In this study, we developed a novel electrochemical sensor for measuring ascorbic acid (AA) or vitamin C (C6H8O6) in urine samples. The sensor was designed using a glassy carbon electrode that was modified with a nanocomposite of Au-Cu2O and MWCNTs. We investigated the characteristics of the nanocomposite using FE-SEM, TEM, XRD, and EDS. Cyclic voltammetry (CV) was used to determine the electrochemical behavior of the modified electrode and how AA is electrooxidized. Based on the electrochemical experiments, the sensor can detect trace levels of AA through voltammetry at a working potential of 0.5 vs. Ag/AgCl. We studied and modified several experimental parameters such as the supporting electrolyte, accumulation potential, solution pH, accumulation time, and amount of modifier to optimize the performance of the sensor. Furthermore, the proposed electrode exhibited a wide linear dynamic range of 1–200 μM, with a low detection limit (S/N = 3) of 0.3 μM. The use of MWCNT semiconductors and Au nanoparticles in electrode modification likely contributed to these favorable results. The outstanding properties of the nanocomposite include a large surface area, exceptional electrical conductivity, and strong electrocatalytic activity.

Development and characterization of chia oil-activated ginger starch-feather keratin biocomposite for prolonged post-harvest preservation of tomato fruits

In response to the challenges posed by current postharvest preservation methods, this study focuses on the development and characterization of a ginger starch-waste feather keratin (GS-FK) composite functionalized with chia oil (CO). Composite films functionalized with 0.5 (GS-FK-CO0.5), 1.0 (GS-FK-CO1.0), and 1.5 (GS-FK-CO1.5) mL of chia oil were fabricated and characterized using standard analytical techniques. GS-FK-CO films in comparison to GS-FK showed increases in thickness and tensile strength, as well as reductions in moisture content, transparency, water solubility, WVP, and elongation at break. GS-FK-CO films demonstrated superior thermal stability and were evaluated for their efficacy in the post-harvest management of tomato fruits. Following coating and storage at 25 ± 2 °C for 21 days, the GS-FK-CO coated tomato fruits exhibited significantly (p > 0.05) lower weight loss, pH, brix value, and ripening index compared to the uncoated control. GS-FK-CO coated fruits in comparison to control displayed elevated levels of titratable acidity, ascorbic acid, and total phenolic acid, along with suppressed activities of polyphenol oxidase, pectin methyl esterase, and polygalacturonase. This study underscores the potential of the chia oil functionalized GS-FK biocomposite as a promising packaging alternative for extended shelf life and enhanced preservation of tomato fruits.

Effects of biofertilizer on the production of bell pepper (Capsicum annuum L.) in greenhouse

Biological fertilizers are useful sources of plant nutrients that enhance crop growth and quality, produce plant hormones, and contribute to sustainable crop production by maintaining soil fertility. The effect of arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPRs) applications in greenhouses on bell pepper (Capsicum annuum L. Nervin) has been studied by conducting a split plot experiment in three replications using a randomized complete block design. The biofertilizers included AMF inoculations (Rhizophagus irregularis + Funneliformis mosseae), and three different bacterial inoculations (Azotobacter chroococcum + Azospirillum lipoferum; Enterobacter cloacae + Pseudomonas putida; Bacillus subtilis + Bacillus amyloliquefaciens) and non-inoculation as a control with two levels of organic fertilizers (with and without).The organic treatment fertilizer, in combination with the inoculation of E. cloacae + P. putida or A. chroococcum + A. lipoferum, as well as AMF, significantly increased the microbial population within the rhizosphere compared to the control. In all treatments, fruit yield increased, with the highest value (15.94 kg m−2) recorded in the AMF treatment, indicating an increase of 18% over the control. All inoculations significantly increased total phenol and ascorbic acid levels in fruit when organic fertilizer was applied. The most significant N uptake was observed in A. crococcum + A. lipoform inoculation, while the most significant Fe uptake was observed in AMF. It was found that all inoculations significantly increased P, K, and Zn uptake. In conclusion, A combination of organic fertilizer and mycorrhizal or (Azotobacter chroococcum + Azospirillum lipoferum) inoculations increased the productivity and quality of bell peppers grown in greenhouses.

Decentralized touch-based micronutrition sensor towards personalized nutrition: Parallel detection of sweat ascorbic acid and zinc ions

The zinc (Zn) and ascorbic acid (AA) micronutrient duo has received a considerable attention in individual’s nutrition plans, particularly after the recent pandemic, owing to its distinct beneficial impact on boosting the immune system. Accordingly, there are growing needs for frequent and decentralized measurements of the trace element and micronutrient levels towards well-balanced personalized nutrition. Leveraging natural sweat sampling from the fingertip, we describe here a disposable electrochemical sensor array, consisting of neighboring Zn ion (Zn(II)), and AA electrodes, towards parallel touch-based on-site monitoring of dynamically-changing sweat Zn(II), and AA levels, following the intake of the corresponding nutrition supplements.. A highly permeable poly (vinyl alcohol) (PVA) hydrogel, placed on the dual-electrode sensor array, served for transferring the sweat from the fingertip onto the electrode surface. Zn(II) measurements were performed on a bismuth/Nafion modified screen printed electrode (SPE) with square-wave anodic stripping voltammetry (SWASV), while the AA detection relied on recording of the open circuit potential (OCP) change, on the tetrathiafulvalene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) immobilized SPE. Rapid decentralized measurements of sweat Zn(II) and AA temporal profiles were carried out on the fingertip sweat of healthy subjects after consuming pill supplements in connection to the disposable strip along with hand-held electrochemical analyzer. The utility of the touch-based disposable Zn(II)/AA multisensory platform for parallel measurements of this pair of micronutrients was demonstrated towards personalized nutrition by providing real-time monitoring of the dose-response relationship. Our findings indicate that the new sweat nutrition sensing device holds considerable promise for guiding dietary interventions and enhancing personalized nutrition.

Revisiting the role of ascorbate oxidase in plant systems.

Ascorbic acid (AsA) plays an indispensable role in plants, serving as both an antioxidant and a master regulator of the cellular redox balance. Ascorbate oxidase (AO) is a blue copper oxidase that is responsible for the oxidation of AsA with the concomitant production of water. For many decades, AO was erroneously postulated as an enzyme without any obvious advantage, as it decreases the AsA pool size and thus is expected to weaken plant stress resistance. It was only a decade ago that this perspective shifted towards the fundamental role of AO in orchestrating both AsA and oxygen levels by influencing the overall redox balance in the extracellular matrix. Consistent with its localization in the apoplast, AO is involved in cell expansion, division, resource allocation, and overall plant yield. An increasing number of transgenic studies has demonstrated that AO can also facilitate communication between the surrounding environment and the cell, as its gene expression is highly responsive to factors such as hormonal signaling, oxidative stress, and mechanical injury. This review aims to describe the multiple functions of AO in plant growth, development, and stress resilience, and explore any additional roles the enzyme might have in fruits during the course of ripening.

Evaluation of the wound healing effect of Nishamalaki, an Ayurvedic formulation comprising Curcuma longa and Phyllanthus emblica in aging rats

BackgroundThere are very few drugs available for healing wounds in the aged population, which is more prone to chronic cutaneous wounds that are particularly hard to heal and require a long healing process. This study which deals with age-related wound healing, investigates the healing effect of Nishamalaki, a classic antidiabetic Ayurvedic formulation comprising turmeric (Curcuma longa) and Indian gooseberry (Phyllanthus emblica), on cutaneous wounds in aging rats.MethodsRats with excision wounds of 7 mm created on their dorsal side received Nishamalaki (500 mg/kg p.o) daily, or a combination of Nishamalaki (500 mg/kg p.o) with 1% Nishamalaki gel applied on the wound or the reference standard metformin (2 μmol) applied on the wound daily till the scabs fell off.ResultsAll treatments enhanced the rate of formation of granulation tissue and wound contraction. All treated rats showed lower blood glucose levels compared with their 1st-day values and significantly lower blood glucose levels when compared with the Aged Control rats. A significant restoration of the aging-depleted L-hydroxyproline, hexosamine, ascorbic acid, PDGF, AMPK, and mTOR levels, and attenuation of the aging-elevated IL-6 and TNF-α levels was elicited by all treatments. The treatments significantly restored the aging-depleted endogenous antioxidants. The Nishamalaki combination treatment of the oral extract and topical gel displayed a better wound-healing effect than the oral treatment alone. The histopathological studies on skin ulceration, hair follicles, granulation tissue, and collagen fiber formation of the wound tissues corroborated the biochemical findings.ConclusionCurcumin and other antioxidant polyphenolic components of Nishamalaki may be responsible for its wound-healing effect. For the first time, the present study has investigated the action of PDGF, AMPK, and mTOR on cutaneous wounds. They seem to be acting together to promote wound healing and repair.Graphical

Impact of Foliar Application of Urea and Nano Urea Levels on Quality, Physiological and Leaf Nutrient Content Attributes of Acid Lime (Citrus aurantifolia Swingle) cv. Kagzi in Vertisols of Jhalawar District in Rajasthan

This study attempted the efficacy of various Urea and Nano urea treatments on Kagzi lime fruit characteristics, such as weight, length, breadth of juice recovery, total soluble solids (TSS), acidity, TSS/Acidity ratio ascorbic acid content, and pH value of juices. There were some significant differences in the reaction of Kagzi lime to these treatments. The Urea treatment at 2% (T4) always gave the top values for the fruit weight, length, breadth; juice recovery, TSS content, TSS/Acidity ratio; ascorbic acid content, and juice pH. While the Nano urea treatments showed positive effects, Urea treatment at 2% had the overall better performance. This implies that Urea at this level was superior in improving the fruit quality factors, which may be used to optimize Kagzi lime cultivation methods. In particular, the variables such as fruit characteristics, juice properties and nutritional content, chlorophyll content; relative water contents in leaves of leaf nutrient contents were positively influenced by 2.0% treatment Urea application These protocols led to significant improvements in fruit weight, length, and width being greater as good juice contented and TSS which increased considerably the levels of Ascorbic acid were improved, chlorophyll content enhanced while there were reduced effects despite that resulted from this prophylactic treatment. Moreover, it resulted in the maximum level of leaf nitrogen and phosphorous. These results show that Urea has significant influences on the quality of acid lime cv. The highest favorable results were noticed in the 2.0% Urea treatment administered by Kagzi lime.

Short-term anaerobic treatment maintained the quality of Actinidia arguta by activating the antioxidant defense system.

This study aimed to investigate the effect of 6, 12, and 24 h short-term anaerobic treatment on kiwiberry quality and antioxidant properties at 5 °C. Short-term anaerobic treatment was found to delay ripening and softening in kiwiberries, evident from changes in ethylene release, total soluble solids, starch, protopectin, and fruit texture. The 24 h treatment group exhibited the lowest decay rate of 12% on day 49, a 38% reduction compared with the control group. Anaerobic treatment reduced flesh translucency and decay in the fruit. The 12 h and 24 h treatments enhanced the activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, and increased the level of total phenolics, flavonoids, anthocyanins, and ascorbic acid. Moreover, it lowered oxidative damage in cell membranes, evidenced by reduced malondialdehyde content and relative conductivity. These results indicate that anaerobic treatment maintains the fruit quality by stimulating its antioxidant defense system. Therefore, short-term anaerobic treatment emerges as a promising method for kiwiberry storage. © 2024 Society of Chemical Industry.

Multiple Physiological and Biochemical Functions of Ascorbic Acid in Plant Growth, Development, and Abiotic Stress Response.

Ascorbic acid (AsA) is an important nutrient for human health and disease cures, and it is also a crucial indicator for the quality of fruit and vegetables. As a reductant, AsA plays a pivotal role in maintaining the intracellular redox balance throughout all the stages of plant growth and development, fruit ripening, and abiotic stress responses. In recent years, the de novo synthesis and regulation at the transcriptional level and post-transcriptional level of AsA in plants have been studied relatively thoroughly. However, a comprehensive and systematic summary about AsA-involved biochemical pathways, as well as AsA's physiological functions in plants, is still lacking. In this review, we summarize and discuss the multiple physiological and biochemical functions of AsA in plants, including its involvement as a cofactor, substrate, antioxidant, and pro-oxidant. This review will help to facilitate a better understanding of the multiple functions of AsA in plant cells, as well as provide information on how to utilize AsA more efficiently by using modern molecular biology methods.

Alleviation of lead stress in sunflower (Helianthus annuus L.) by growth-promoting rhizobacterium and neem cake

ABSTRACT Lead causes toxicity and affects plant growth by disturbing photosynthesis and the functions of enzymes. Its removal from the soil is a challenging issue. The present study investigates the efficacy of neem cake as soil organic amendment and inoculation of a lead-tolerant plant growth-promoting rhizobacterium (PGPR), Pseudomonas aeruginosa, to decrease the effects of lead toxicity in sunflower, when cultivated with and without neem cake amended soil. The experiment was performed in earthen pots (10 cm diam) containing 1 kg sandy loam soil irrigated with 0.2 and 0.5 mM lead. P. aeruginosa used in this experiment has a lead remediation capacity of 99% when subjected to 0.6 mM lead. The combination of organic amendment with PGPR improved the growth and physiological performance of the stressed sunflower plant. The plants treated with PGPR in amended soil showed healthier roots and shoots and demonstrated better scavenging of free radicals, with improved H2O2 scavenging and peroxidase (POD) activities. Neem cake and P. aeruginosa separately and combined significantly enhanced sugar contents and POD activity while lowering stress-induced higher levels of phenols and ascorbic acid. The combined application of neem cake and P. aeruginosa could be a promising solution for growing sunflower plants in lead-contaminated soil.

Ascorbic acid deficiency amongst spondylodiscitis patients.

Spondylodiscitis can be a disabling and life-threatening infection. Ascorbic Acid is crucial for neutrophil function and collagen formation. Its association and clinical relevance in spondylodiscitis has not been previously examined. To determine the prevalence, characteristics, and clinical outcomes of spondylodiscitis patients with Ascorbic Acid deficiency. Sixty-eight consecutive patients admitted with spondylodiscitis, between December 2021 and August 2023 were included. Clinical characteristics, Ascorbic Acid levels and clinical outcomes were evaluated. Thirty-seven patients had Ascorbic Acid levels taken during admission. The median initial Ascorbic Acid level was 15 μmol/L with an IQR 6.5-27 μmol/L. Depletion defined as <28 μmol/L was present in 78% of patients. Deficiency defined as ≤11 μmol/L was present in and 46% of patients. Patients with depletion were more likely to require Intensive Care Admission (absolute risk increase = 24.1%; 2.6%-45.7%). Fifteen patients had repeat serum levels taken during admission with median increase of 17 μmol/L and an IQR 0-26 μmol/L. Patients that received supplementation had a significantly greater increase in Ascorbic Acid levels compared with those that did not receive supplementation (P = 0.002). Ascorbic acid deficiency is highly prevalent amongst spondylodiscitis patients. Depletion was associated with worse outcomes. Replacement significantly increased serum levels in comparison to standard hospital diet. The clinical significance of replacement remains to be evaluated.

Higher serum ascorbic acid levels are associated with lower depression prevalence in US adults: a case-control study.

Recent studies have shown that a higher intake of ascorbic acid was associated with a lower prevalence of depression. Nevertheless, the recall bias was common in dietary surveys in these studies, and it was ignored that there were differences in the absorption and utilization of ascorbic acid in the body. Hence, we aim to investigate the association between serum ascorbic acid levels and the prevalence of depression in US adults. A total of 3,404 participants from the 2017-2018 National Health and Nutrition Examination Survey (NHANES) that underwent measurement of the Patient Health Questionnaire-9 (PHQ-9) scores and serum levels of ascorbic acid. Propensity Score Matching (PSM) successfully established a case-control study, comprising 299 participants diagnosed with depression and 1,107 as controls. We used binary logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to explore associated risk factors for depression. Restricted cubic splines (RCS) were used to show the nonlinear relationship between serum ascorbic acid levels and the prevalence of depression. The prevalence of depression was approximately 8.8%, with a median serum ascorbic acid level of 49.9 (36.0, 67.0) μmol/L. Results revealed that the serum ascorbic acid levels of depressed patients were significantly lower than those of non-depressed individuals (42.97 VS 52.97 μmol/L). The baseline data indicated that as serum ascorbic acid levels increased from Quartile 1 (Q1) to Quartile 4 (Q4), the depression prevalence decreased from 12.0 to 5.4% (p < 0.05). The results of the chi-square test after PSM showed that serum ascorbic acid was still statistically significant (p < 0.001) with the prevalence of depression. Forest plot showed that compared with the Q1 of serum ascorbic acid level, the OR and 95%CI of depression prevalence in Q4 was 0.42 (0.30 ~ 0.61), and the adjusted OR and 95%CI of depressive prevalence was 0.49 (0.33 ~ 0.73). RCS models showed an L-shaped nonlinear relationship (P for nonlinearity <0.05) between serum ascorbic acid and depression. Our results suggested that higher serum ascorbic acid levels are associated with a reduced prevalence of depression.

Water deprivation-induced hypoxia and oxidative stress physiology responses in respiratory organs of the Indian stinging fish in near coastal zones.

Water deprivation-induced hypoxia stress (WDIHS) has been extensively investigated in numerous fish species due to their adaptation with accessory respiratory organs to respire air but this has not been studied in Indian stinging fish Heteropneustes fossilis. Data regarding WDIHS-induced metabolism in accessory respiratory organ (ARO) and gills and its relationship with oxidative stress (OS) in respiratory organs of air-breathing fish H. fossilis, are limited. So, this study aimed to investigate the effects of WDIHS (0, 3, 6, 12, and 18 h) on hydrogen peroxide (H2O2) as reactive oxygen species (ROS), OS, redox regulatory enzymes, and electron transport enzymes (ETC) in ARO and gills of H. fossilis. Fish were exposed to air for different hours (up to 18 h) against an appropriate control, and ARO and gills were sampled. The levels of oxygen saturation in the body of the fish were assessed at various intervals during exposure to air. Protein carbonylation (PC) and thiobarbituric acid reactive substances (TBARS) were used as OS markers, H2O2 as ROS marker, and various enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), along with the assessment of complex enzymes (I, II, III, and V) as well as the levels of ascorbic acid (AA) and the reduced glutathione (GSH) were quantified in both the tissues. Discriminant function analyses indicate a clear separation of the variables as a function of the studied parameters. The gills exhibited higher levels of GSH and H2O2 compared to ARO, while ARO showed elevated levels of PC, TBARS, AA, SOD, CAT, and GPx activities compared to the gills. The activities of GR and ETC enzymes exhibited similar levels in both the respiratory organs, namely the gills, and ARO. These organs experienced OS due to increased H2O2, TBARS, and PC levels, as observed during WDIHS. Under WDIHS conditions, the activity/level of CAT, GPx, GR, and GSH decreased in ARO, while SOD activity, along with GR, GSH, and AA levels decreased in gills. However, the activity/level of SOD and AA in ARO and CAT in gills was elevated under WDIHS. Complex II exhibited a positive correlation with WDIHS, while the other ETC enzymes (complex I, III, and V) activities had negative correlations with the WDIHS. The finding suggests that ARO is more susceptible to OS than gills under WDIHS. Despite both organs employ distinct redox regulatory systems to counteract this stress, their effectiveness is hampered by the inadequacy of small redox regulatory molecules and the compromised activity of the ETC, impeding their ability to effectively alleviate the stress induced by the water-deprivation condition.

Phytochemical composition and biological activity of native Australian ginger (Alpinia caerulea)

The edible, endemic Australian species Alpinia caerulea belongs to the same family as ginger and turmeric. The rhizome and fruit have a mild ginger-like flavour, but there is very little information on its chemical composition or potential biological activities. This study found low levels of ascorbic acid in the fruit and fruit capsule (2.3–3.4 mg/100 g fresh weight), as well as detecting six polyphenols (rutin, quercetin-3-glucoside, quercetin, vanillic acid, kaempferol and chlorogenic acid) across all of the plant parts. The volatile profile of the rhizome was also explored for the first time. The volatiles were dominated (91.7%) by (E)-8(17),12-labdadiene-15,16-dial, but included 20 other minor constituents; mainly monoterpenes and sesquiterpenes. Extracts showed no inhibitory activity against tyrosinase or cyclooxygenase-2 (COX-2), but moderate anti-acetylcholinesterase was found for the rhizome and stem extracts. Further investigation into A. caerulea and other species from this genus will help to elucidate their full nutritional and bioactive potential.

Influence of Pasteurisation (Conventional vs. Radiofrequency) and Chill Storage on Retention of Ascorbic Acid, Tocopherol and Carotenoids in Salmorejo.

Salmorejo, a Mediterranean tomato-oil puree, is considered a dietary source of antioxidant vitamins C and E and carotenoids lycopene and β-carotene, the latter endowed with provitamin A activity. However, these antioxidants can be degraded in oxidation reactions catalysed or not by enzymes during pasteurisation and storage treatments used to stabilise the salmorejo before consumption. Due to its better penetration, the use of dielectric heating by radiofrequency (RF) may improve results of pasteurisation in this product. The objective was to assess the effects of pasteurisation temperature (70-100 °C, at 5 °C intervals) and storage time (0-5 months, at one-month intervals) on levels of ascorbic acid, α-tocopherol and carotenoids and antioxidant capacity (AC) in salmorejo pasteurised (over 10 s) by conventional (CH) or RF continuous heating. Two successive experiments were conducted to select an adequate pasteurisation temperature for use in the shelf-life study. Pasteurisation upon tested conditions allows a good retention of salmorejo antioxidants. Either CH or RF pasteurisers can be used with similar results. Vitamin C (L-ascorbic + dehydroascorbic acids) was more abundant (15-19 mg 100 g-1) than carotenoids (0.9-2.6 mg 100 g-1) (all-trans + cis lycopene and β-carotene) and α-tocopherol (0.8-1.2 mg 100 g-1) in the pasteurised product. Using excessively low temperatures (70 °C) resulted in partial losses of the three antioxidants, possibly due to oxidase residual activities. Intensifying thermal treatment improved this issue with minor losses of the thermolabile vitamin C and increased carotenoid content. Using a suitable temperature (80 °C) did not prevent most vitamin C from being degraded by the first month, while α-tocopherol, and, to a lesser extent, carotenoids, showed good retention levels during shelf life under refrigeration. Vitamins C and E and carotenoids, either by degradation, regeneration or releasing, likely contribute to the AC in salmorejo. Phenolic antioxidant response, radical-scavenging activities and redox potential values confirmed this finding. The pasteurised-chilled salmorejo shows good antioxidant properties with potential health implications, a positive nutritional aspect for consumers of this tomato-oil homogenate. The losses of antioxidants and AC due to pasteurization would be of little relevance compared to the losses accumulated during shelf life.

Natural Enzyme-Inspired Design of the Single-Atom Cu Nanozyme as Dual-Enzyme Mimics for Distinguishing Total Antioxidant Capacity and the Ascorbic Acid Level.

Although various oxidase mimetic or peroxidase (POD) mimetic nanozymes have been extensively studied, their poor substrate selectivity significantly inhibits their practical applications. Nanozymes with specific biomolecules as substrates, especially ascorbic acid oxidase (AAO) mimetic nanozymes with ascorbic acid (AA) as a substrate, have scarcely been studied. Herein, inspired by the multi-Cu atom sites and the redox electron transfer pathway of Cu2+/Cu+ in the natural AAO, atomically dispersed Cu sites immobilized on N-doped porous carbon (Cu-N/C) are artificially designed to simulate the function of natural AAO. Compared with their natural counterparts, the Cu-N/C catalysts exhibited higher catalytic efficiency and superior stability. Combined theoretical calculation and experimental characterizations reveal that the Cu-N/C nanozymes could catalyze the AA oxidation through a 2e- oxygen reduction pathway with H2O2 as the product. Moreover, the Cu-N/C nanozymes also possess high POD activity. As a proof-of-concept application, Cu-N/C can simultaneously realize AA detection in fluorescent mode based on its AAO activity and total antioxidant capacity detection in colorimetric mode utilizing its POD activity.