Effects of solvent extraction on the phytoconstituents and in vitro antioxidant activity properties of leaf extracts of the two selected medicinal plants from Malawi.

This study evaluated and compared the phytochemical and antioxidant properties of the solvent extracts of Azadirachta indica A. Juss and Vernonia amygdalina Del leaves. Methanolic and aqueous extracts showed high (P ≤ 0.05) extract yields (in %), compared to chloroform and ethyl acetate extracts from both V. amygdalina and A. indica leaves. The study exhibited high phytochemical content in methanol and aqueous extracts compared to chloroform and ethyl acetate extracts, confirming the potential for medicinal use. V. amygdalina methanol and aqueous extracts had higher (P ≤ 0.05) total phenolic content (TPC), in mg GAE/gDW, (158.810±0.846 and 217.883±0.265, respectively) than chloroform (37.574±0.118) and ethyl acetate (104.758±0.236) but higher ethyl acetate content in A. indica extracts. Low polar solvents extracted high (P ≤ 0.05) total flavonoids, in mgQE/gDW, (367.051±0.858 and 149.808±0.009) compared to high polar solvents (14.863±0.071 and 54.226±0.014 ) in V. amygdalina while as in A. indica leaf extracts, low polar solvents showed high TFC ( 658.469±3.451 and 275.288±10.490) compared to high polar solvents (26.312±0.063 and 48.858±0.063) respectively. In vitro total antioxidant capacity, in mg/g, was higher in polar solvents than in low-polar solvents, ranging from 34.300±1.784 to 121.015±6.839 for A. indica ethyl acetate and methanolic extracts. A strong correlation between TPC and tannic acid content was observed, except in A. indica methanolic extracts of A. indica. Ferric reducing power was high, except for V. amygdalina chloroform and methanol leaf extracts, which were lower (P≤ 0.05) than that of the standard ascorbic acid. The study revealed that high polar solvents, such as methanol and water, are more efficient in the extraction of antioxidants from A. indica but lower in V. amygdalina extracts. High phytochemical content and antioxidative capacity could be significant in treating various diseases in humans.

Synergistic effect of selected carboxylic acids and phenolic compounds detected by the FRAP method.

Antioxidants in nutrition are a widely discussed topic. In this study, a synergistic effect was observed for 13 selected substances - antioxidants and potential synergists, whereby two substances were mixed in the same concentration ratio of 1:1. The antioxidant capacity (AC) of the mixtures was determined using the FRAP method. The AC measured was compared with a theoretical AC value (as only additive effect) to calculate the synergistic or antagonistic effect. Out of 78 possible combinations, a synergistic effect (SE) was detected in 72. For the 10 combinations, the SE was more than twice that of the pure substances. The largest synergistic effect was exhibited by vanillin and 4-hydroxybenzoic acid with increases even above 200% compared to the pure substances. Some of the phenolic substances that were subject to measurement can be used for the fortification of fruit juices.

Influence of Harvesting Stages on Phytonutrients and Antioxidant Properties of Leaves of Five Purple-Fleshed Sweet Potato (Ipomoea batatas) Genotypes.

Sweet potatoes (Ipomoea batatas) are highly profitable, contribute to food security, and their leaves rich in phytonutrients. This study examined the optimal leaf harvesting stage by harvesting newly formed leaves (leaves 1 to 5) to achieve the highest concentration of carotenoids, phenolic compounds, antioxidant properties and mineral content. Leaves of five purple-fleshed sweet potato genotypes '2019-11-2' and '2019-1-1', 'Purple-purple', and from the USA '08-21P' and '16-283P' were harvested based on tuber life cycle [vegetative 8 weeks after planting (VS-8WAP), tuber initiation (TIS-12WAP), and tuber maturation phases (TMS-16WAP)]. At the 8WAP stage, leaves of genotype '2019-11-2' had the highest concentrations of cyanidin-caffeoyl-sophoroside-glucoside (17.64 mg/kg), cyanidin-caffeoyl-feruloyl-sophoroside-glucoside (41.51 mg/kg), peonidin-caffeoyl-hydroxybenzoyl-sophoriside-glucoside (45.25 mg/kg), and peonidin caffeoyl-feruloyl-sophoriside-glucoside (24.47 mg/kg), as well as antioxidant scavenging activity. In contrast, 'Purple-purple' harvested at TIS-12WAP showed the highest concentration of caffeoylquinic acid derivatives. Zeaxanthin, lutein, all trans-ß-carotene, and cis-ß-carotene are the most abundant carotenoids in genotype '08-21P' at VS-8WAP. As a result, local genotypes '2019-11-2' harvested at 8WAP and 'Purple-purple' harvested at 12WAP are potential sources of anthocyanins and caffeoylquinic acid derivatives. Conversely, USA's genotype '08-21P' at the VS-8WAP stage is an excellent source of carotenoids. The leaves of USA's '08-21P' genotype and the local '2019-11-2' genotype at TMS-16WAP exhibited the highest content of Fe and Mn, respectively. The study identified the optimal leaf stage for consumption of leaves and for use as a functional ingredient.

Use of Botanical Ingredients: Nice Opportunities to Avoid Premature Oxidation of NABLABs by Increasing Their ORAC Values Strongly Impacted by Dealcoholization or Pasteurization.

Even when fresh, non-alcoholic, and low-alcoholic beers (NABLABs) exhibit significant staling defects due to premature oxidation. In this study, the antioxidant power of eleven fresh commercial NABLABs was assessed by means of three different assays: the oxygen radical absorbance capacity (ORAC), the linoleic acid-induced oxidation (TINH), and the indicator time test (ITT). Only the first two assays, both involving radicalar degradations initiated by AAPH, were found to correlate with each other. NABLABs displayed lower ORAC values than conventional beers (on average, 6127 µmol eq. Trolox/L), except for three samples made with special-colored malts or dry-hopped. Dealcoholization was the step with the greatest impact on the ORAC value (up to a 95% loss) and on flavan-3-ols, sotolon, and polyfunctional thiols, while pasteurization strongly affected color, TBA, and Strecker aldehydes. ORAC assays applied to hop, alternative cereals, and various botanical ingredients indicated that mashing with red sorghum, dry hopping/spicing, and wood maturation could bring the antioxidant power of a NABLAB close to those of conventional beers. With an ORAC value not reached by any other tested botanical ingredient (5234 µmol eq. Trolox/g), African Vernonia amygdalina leaves (traditionally used for Rwandan Ikigage beers) emerged here as the best candidate.

Wood Distillate Promotes the Tolerance of Lettuce in Extreme Salt Stress Conditions.

Soil salinization is an adverse phenomenon in agriculture that severely affects crop growth and yield. The use of natural products, such as wood distillate (WD, derived from the pyrolysis of woody biomass), could be a sustainable approach to enhance the tolerance of plants cultivated in the saline soils. Hence, this study aimed to evaluate the potential of WD, a foliar sprayed at 0.2% (v/v), in lettuce plants subjected to grow under both moderate and high soil sodium chloride (NaCl) concentrations (ranging from 0 to 300 mM). The changes in the physiological and biochemical responses of these plants to the varying salt stress conditions allowed the identification of a maximum tolerance threshold (100 mM NaCl), specific to lettuce. Beyond this threshold, levels related to plant defense antioxidant power (antiradical activity) were lowered, while those indicative of oxidative stress (malondialdehyde content and electrolyte leakage) were raised, causing significant losses in leaf fresh biomass. On the other hand, WD significantly improved plant growth, enabling plants to survive high salt conditions >200 mM NaCl. Collectively, these observations highlight that treatments with WD could be of paramount importance in coping with current environmental challenges to have better yields under soil conditions of high salt concentrations.

The Effect of Water Stress on Bioactive Compounds in Australian-Grown Black Sesame.

Sesame is an emerging crop of interest in Australia and has attracted widespread interest due to the health-benefitting properties of its bioactive compounds, including fatty acids, lignans, and polyphenols. This study aimed to investigate the impact of drought stress on these bioactive compounds, using eleven cultivars of black sesame seeds grown in Australia. Specific varieties responded positively to water deficit (WD) conditions, showing increased levels of TPC, FRAP, CUPRAC, and lignans. Varieties 1, 4, 7, and 12 showed significantly increased FRAP values ranging from 158.02 ± 10.43 to 195.22 ± 9.63 mg TE/100 g DW in the WD treatment compared to the well-watered (WW) treatment, whereas varieties 7, 10, 12, 13, and 18 demonstrated the highest CUPRAC values of all varieties (2584.86 ± 99.68-2969.56 ± 159.72 mg TE/100 g) across both WW and WD conditions, with no significant variations between irrigation regimes. Moreover, lignan contents (sesamin and sesamolin) were higher in varieties 1, 2, 5, and 8 grown in WD conditions. Compared to the optimal unsaturated to saturated fatty acid ratio (Σ UFA/Σ SFA ratio) of 0.45, all sesame genotypes showed superior ratios (ranging between 1.86 and 2.34). Moreover, the ω-6/ω-3 PUFA ratio varied from 33.7-65.5, with lower ratios in varieties 2, 4, 5, 8, and 18 under WD conditions. The high levels of phenolic compounds and healthy fats suggest the potential of black sesame to be incorporated into diets as a functional food. Furthermore, the enhanced phytochemistry of these cultivars in WD conditions is promising for widespread adoption. However, larger trial studies to confirm these findings across different geographic locations and seasons are warranted.

Phytonutritional Composition and Antioxidant Properties of Southern African, Purple-Fleshed Sweet Potato (Ipomoea batatas (L.) Lam.) Storage Roots.

Purple sweet potatoes (Ipomoea batatas (L.) genotype) in Southern Africa have a phytonutritional composition and antioxidant properties that can increase incomes and improve nutrition. This study compared the phytonutrient composition and antioxidant properties of four purple-colour sweet potato genotypes (local Purple-purple, '2019-1-1', and USA genotypes, '08-21P' and '16-283P'). These purple sweet potato genotypes were characterised by UPLC/QTOF/MS and 16 phenolic compounds were identified. Purple-purple (very dark purple) showed the highest concentration of cyanidins and peonidin derivatives. Chlorogenic acid derivatives were highest in the genotype '16-283P'. 'Puple-purple' and '16-283P' displayed the strongest antioxidant power and scavenging activities. Diaffeoylquinic acid isomer 1 was identified as the marker candidate for distinguishing the four purple sweet potato genotypes. Southern Africa's highest-protein sweet potato genotypes are Purple-purple (28.81 g/100 g) and '08-21 P' (24.31 g/100 g). A 13.65 g portion of '2019-1-1' would meet the Recommended Dietary Allowance (RDA) for iron for men, while 25.59 g would meet the RDA for children, and 30.72 g would meet the RDA for women. The sweet potato root of genotype '2019-1-1' provides 31.43 g of Zn per day for children and 22.86 g for adults. The roots of local cultivar Purple-purple can be used as functional food ingredients.

Primary Antioxidant Power and Mpro SARS-CoV-2 Non-Covalent Inhibition Capabilities of Miquelianin.

The antioxidant power of quercetin-3-O-glucuronide (miquelianin) has been studied, at the density functional level of theory, in both lipid-like and aqueous environments. In the aqueous phase, the computed pKa equilibria allowed the identification of the neutral and charged species present in solution that can react with the ⋅OOH radical. The Hydrogen Atom Transfer (HAT), Single Electron Transfer (SET) and Radical Adduct Formation (RAF) mechanisms were considered, and the individual, total and fraction corrected rate constants were obtained. Potential non-covalent inhibition of Mpro from SARS-CoV-2 by miquelianin has been also evaluated.

Development of a functional Greek sheep yogurt incorporating a probiotic Lacticaseibacillus rhamnosus wild-type strain as adjunct starter culture.

Greek yogurt is a fermented dairy product of high nutritional value that can be used as a matrix for the delivery of probiotics. The aim of this study was to develop a new probiotic Greek sheep yogurt with upgraded quality and functional characteristics. To do this, yogurt was manufactured by fermenting pasteurized milk with the commercial starter culture (Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB)) together with a probiotic Lacticaseibacillus rhamnosus (LR) wild-type strain (probiotic yogurt; PY). As a control, yogurt manufactured with only the starter culture (ST, LB) was used (conventional yogurt; CY) The survival of all three lactic acid bacteria (LAB) species (ST, LB, and LR) was monitored throughout the products' shelf life (storage at 4 °C for 25 days), and also following exposure to a static in vitro digestion model (SIVDM). The population dynamics of total aerobic plate count (APC), Enterobacteriaceae, yeasts and molds grown in both yogurts were also determined. The total antioxidant activity (AA) of yogurts was comparatively determined using in parallel two different assays, whereas the Folin-Ciocalteu assay was used to determine their total phenolic content (TPC). At each sampling day, yogurts were also evaluated for their pH, titratable acidity (TA) and main sensory characteristics. The population of probiotic LR remained stable during the shelf life (and above 108 CFU/g). Yogurt starters (ST, LB) were not detected following SIVDM, whereas LR (in PY) presented a reduction of about only one log. The AA and TPC of PY were found significantly higher than that of CY (P < 0.05). At the end of storage (25th day), neither pH nor TA differed significantly between the two yogurt types, while no fungal growth was observed in the PY. Consumer sensory analysis did not reveal important differences between the two yogurt types during their shelf life. To sum up, the novel yogurt was able to deliver to consumers a high number of probiotic cells (>108 CFU/g), presented increased antioxidant power, had an expanded shelf life, and maintained its good sensory attributes.

Assessment of Drimia delagoensis (Jessop) Baker Total Phenol, Flavonoids Content and Antioxidant Activity of Both Bulb and Leaves.

Drimia delagoensis has been utilized for its medicinal properties since antiquity. The bulb and leaves are predominantly composed of secondary metabolites that exhibit biological activity. The quantification of total phenolic and flavonoid content, as well as the assessment of antioxidant activity was conducted using the Folin-Ciocalteus method, coulometric analysis, DPPH and the FRAP assays. The ethyl acetate, aqueous, and hexane extracts of the bulb exhibited significantly high total phenolic contents (167.9000±0.3376 µg GAE/mg, 56.2500±0.0043 µg GAE/mg, and 26.4000±0.0198 µg GAE/mg, respectively) compared to the ethyl acetate (49.4400±0.1341 µg QE/mg), aqueous (9.5200±0.1274 µg QE/mg), and hexane leaf extracts (1.8091±0.0049 µg QE/mg). On the other hand, the ethyl acetate leaf extract exhibited the highest antioxidant and free radical scavenging activity. The ethyl acetate extract of D. delagoensis, was identified as a significant source of natural antioxidants, and its use in the management of diabetic foot ulcers linked with oxidative stress is supported.

Hematological parameters, obesity, stress and oxidant - antioxidant indicators in patients with or without recurrent aphthous stomatitis: A case control study.

INTRODUCTION: Recurrent Aphthous Stomatitis (RAS) is a frequent chronic disease of the oral cavity that affects 5-25 % of the population with a plethora of predisposing factors. Despite its equivocal etiology, immune alterations, hematologic deficiencies and oxidative stress has been reported to be significant etiologic factors. Stress and obesity are other environmental factors that have been studied to understand associations with RAS. OBJECTIVES: This study investigated the association of stress, hematologic parameters, oxidative indices and other selected salivary factors in a case control study on RAS Methods: Twenty-two participants each in both case and control groups were recruited with saliva and serum samples collected from them after a self-administered Recent Life Changing Questionnaire (RLCQ). OHI-S and salivary flow rate (SFR) were calculated with selected hematologic parameters and oxidative indices such as Total oxidant (TOS) and anti-oxidant (TAS) levels and their ratio - Oxidative Stress Index (OSI). Anti-oxidative indices of Ferric-Reducing Antioxidant Power (FRAP) and Glutathione Peroxidase Activity (GsPHx) were also estimated. RESULTS: The RAS group had a significantly higher RLCQ scores at a median of 145 more than the control (57.5). There was no significant in their obesity indices, however there was a significant higher mean in the ESR (p< 0.0001) and Vit B12 (p = 0.0001); OHI-S was also significantly higher in the RAS group with a median of 1.65. Both the salivary and serum TOS were significantly higher in the RAS (10.0 ± 3.8, 15.4 ± 8.9) compared to the control group (7.92 ± 1.49, 9.56 ± 3.5). GsPHx activity was significantly higher in both the saliva and serum in the control group (0.08 ± 0.08, 0.19 ± 0.11) while nil significant difference was found in the FRAP activity. Regression showed most important variables to be the salivary GsPHx activity, followed by serum OSI and GsPHx activity. CONCLUSION: The oxidative indices of TOS, TAS and GsPHx can serve as significant biomarkers in detecting RAS. This further corroborates the role of immune dysregulation in the etiology and predisposition to RAS.

Nickel chloride generates cytotoxic ROS that cause oxidative damage in human erythrocytes.

BACKGROUND: Nickel is a heavy metal that is regarded as a possible hazard to living organisms due to its toxicity and carcinogenicity. Nickel chloride (NiCl2), an inorganic divalent Ni compound, has been shown to cause oxidative stress in cells by altering the redox equilibrium. We have investigated the effect of NiCl2 on isolated human erythrocytes under in vitro condition. METHODS: Isolated erythrocytes were treated with different concentrations of NiCl2 (25-500 µM) for 24 h at 37 ºC. Hemolysates were prepared and several biochemical parameters were analyzed in them. RESULTS: Treatment of erythrocytes with NiCl2 enhanced the intracellular generation of reactive oxygen species (ROS). A significant increase in hydrogen peroxide levels and oxidation of proteins and lipids was also seen. This was accompanied by a reduction in levels of nitric oxide, glutathione, free amino groups and total sulfhydryl groups. NiCl2 treatment impaired both enzymatic and non-enzymatic defense systems, resulting in lowered antioxidant capacity and diminished ability of cells to quench free radicals and reduce metal ions. NiCl2 exposure also had an inhibitory effect on the activity of enzymes involved in pathways of glucose metabolism (glycolytic and pentose phosphate shunt pathways). Increased level of methemoglobin, which is inactive in oxygen transport, was also seen. The rate of heme breakdown increased resulting in the release of free iron. Exposure to NiCl2 led to considerable cell lysis, indicating damage to the erythrocyte membrane. This was supported by the inhibition of membrane bound enzymes and increase in the osmotic fragility of NiCl2 treated cells. NiCl2 treatment caused severe morphological alterations with the conversion of normal discocytes to echinocytes. All changes were seen in a NiCl2 concentration-dependent manner. CONCLUSION: NiCl2 generates cytotoxic ROS in human erythrocytes which cause oxidative damage that can decrease the oxygen carrying capacity of blood and also lead to anemia.

Antioxidant and Antibacterial Activities of the Leaf and Stem Extracts of Combretum molle (R. Br. ex G. Don.) Engl. & Diels.

Medicinal plants offer reasonable and accessible alternatives to synthetic drugs and are often devoid of the adverse side effects, toxicity, and pathogenic resistance associated with synthetic medicine. Combretum molle has been utilized in African traditional medicinal practices and purportedly contains bioactive compounds with medicinally beneficial effects. This study investigated the hexane, chloroform, and methanol leaf and stem extracts for their antioxidant properties using the 2,2'-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing antioxidant power assays. The study additionally analyzed the methanol extracts for their antibacterial activity against Gram-negative Escherichia coli (ATCC 25922) and Gram-positive Staphylococcus aureus (ATCC 25923) bacteria using agar well diffusion. Relative to the scavenging activity of the ascorbic acid control (79.15 ± 0.63% at 15 µg/mL to 94.61 ± 0.12% at 240 µg/mL), the plant's radical scavenging activities were exceptionally high in the methanolic leaf and stem extracts (p < 0.05), ranging from 94.58 ± 1.10% at 15 µg/mL to 99.22 ± 0.30% at 240 µg/mL and 91.57 ± 1.71% at 15 µg/mL to 99.60 ± 0.20% at 240 µg/mL, respectively, suggesting a strong capacity to donate hydrogen ions. High scavenging activities were additionally observed in the chloroform stem (78.68 ± 1.18% at 15 µg/mL to 98.14 ± 1.22% at 240 µg/mL) and hexane leaf (72.12 ± 4.38% at 15 µg/mL to 89.87 ± 1.50% at 240 µg/mL) extracts (p < 0.05). All extracts exhibited poor ferric-reducing abilities in relation to the gallic acid control (100 ± 0.00%) at all concentrations (p < 0.05). The leaf and stem extracts exhibited broad-spectrum antibiotic capabilities against both tested strains, with significant activity at higher concentrations (p < 0.05). Overall, both the leaf and stem extracts of C. molle exhibited similar antioxidant and antibacterial activities. These findings warrant further pharmacological research on C. molle for potential drug development.

Mancozeb-induced cytotoxicity in human erythrocytes: enhanced generation of reactive species, hemoglobin oxidation, diminished antioxidant power, membrane damage and morphological changes.

Mancozeb is an ethylene bis-dithiocarbamate fungicide extensively used in agriculture to safeguard crops from various fungal diseases. The general population is exposed to mancozeb through consumption of contaminated food or water. Here, we have investigated the effect of mancozeb on isolated human erythrocytes under in vitro conditions. Erythrocytes were treated with different concentrations of mancozeb (0, 5, 10, 25, 50, 100 µM) and incubated for 24 h at 37 °C. Analysis of biochemical parameters and cell morphology showed dose-dependent toxicity of mancozeb in human erythrocytes. Mancozeb treatment caused hemoglobin oxidation and heme degradation. Protein and lipid oxidation were enhanced, while a significant decrease was seen in reduced glutathione and total sulfhydryl content. A significant increase in the generation of reactive oxygen and nitrogen species was detected in mancozeb-treated erythrocytes. The antioxidant capacity and the activity of key antioxidant enzymes were greatly diminished, while crucial metabolic pathways were inhibited in erythrocytes. Damage to the erythrocyte membrane on mancozeb treatment was apparent from increased cell lysis and osmotic fragility, along with the impairment of the plasma membrane redox system. Mancozeb also caused morphological alterations and transformed the normal discoid-shaped erythrocytes into echinocytes and stomatocytes. Thus, mancozeb induces oxidative stress in human erythrocytes, impairs the antioxidant defense system, oxidizes cellular components, that will adversely affect erythrocyte structure and function.

Curcumin from Curcuma longa Linn. (Family: Zingiberaceae) attenuates hypochlorous acid-induced cytotoxicity and oxidative damage to human red blood cells.

Hypochlorous acid (HOCl) is a major oxidant produced by activated neutrophils via the myeloperoxidase catalyzed reaction. The production of HOCl eliminates a wide range of pathogens. However, HOCl can also cause significant oxidative damage in cells and tissues where it is generated. The protective effect of curcumin was studied on HOCl-induced oxidative damage to human red blood cells (RBC). Isolated RBC were incubated with HOCl at 37 °C in absence or presence of different concentrations of curcumin. Hemolysates were prepared and assayed for various biochemical parameters. Treatment of RBC with HOCl alone increased hemolysis, protein carbonyls, heme degradation and chloramines as compared to untreated control cells. This was accompanied by reduction in glutathione level, total sulfhydryls and free amino groups. HOCl also lowered the activities of major antioxidant enzymes and diminished the antioxidant power of RBC. Pre-treatment of RBC with different concentrations of curcumin resulted in concentration-dependent attenuation in all these parameters while curcumin alone had no significant effect. Scanning electron microscopy showed that curcumin prevented HOCl-induced morphological changes in RBC and restored their normal biconcave shape. Thus curcumin can be used as a chemoprotective agent to mitigate HOCl-induced oxidative damage to cells. These results also explain the beneficial effects of curcumin against Helicobacter pylori induced stomach ulcers, caused by excessive production of HOCl at the site of bacterial infection.

Optimizing an Enzymatic Extraction Method for the Flavonoids in Moringa (Moringa oleifera Lam.) Leaves Based on Experimental Designs Methodologies.

Moringa oleifera Lam. is known to have significant antioxidant properties. Because of this, the development of an optimal extraction method is crucial to obtain pharmacological products based on the bioactive compounds produced by this tree. Through a Plackett-Burman and a Box-Behnken design, enzymatic extraction conditions (temperature, agitation, solvent pH and composition, sample-to-solvent ratio, enzyme-to-sample ratio and extraction time) have been optimized using normalized areas (UA/g) as response variable and relative mass (mg/g) as quantification variable. Extractions were performed in an incubator, where all the extraction conditions could be digitally controlled. Thus, 58.9 °C, 50 rpm, 4.0 pH, 32.5% EtOH, 0.2 g sample in 15 mL solvent and 106 U/g were established as the optimal extraction conditions for the extraction with a mix of pectinases coming from Aspergillus niger. Under these optimal conditions, two-minute extractions were performed and evaluated through a single factor design. The enzymatic extraction method demonstrated its suitability to produce extracts with good antioxidant power (antioxidant activity 4.664 ± 0.059 mg trolox equivalent/g sample and total phenolic compounds 6.245 ± 0.101 mg gallic acid equivalent/g sample). The method was also confirmed to have good repeatability (1.39%) and intermediate precision (2.37%) levels.

Characterization and Classification of Spanish Honeydew and Blossom Honeys Based on Their Antioxidant Capacity.

Honey is a very appreciated product for its nutritional characteristics and its benefits for human health, comprising antioxidant, anti-inflammatory, antifungal, and antibacterial activities. These attributes depend on the specific composition of each honey variety, with the botanical origin as one of the distinctive features. Indeed, honeydew and blossom honeys show different physicochemical properties, being the antioxidant capacity, mainly relying on the phenolic compound content, one of the most important. In this work, Folin-Ciocalteu (FC) index, total flavonoid content (TFC), and the antioxidant capacity based on the ferric reducing antioxidant power (FRAP) assay were determined for a total of 73 honeys (50 blossom honeys and 23 honeydew honeys). Mean content of oxidizable species (FC index) ranges from 0.17 to 0.7 mg eq. gallic acid g-1, with honeydew honeys being the ones with higher values. Regarding TFC, mean values above 1.5 mg eq. quercetin g-1 (method applied in the absence of NaNO2) were obtained for honeydew honeys and heather honey. Lower and not discriminatory values (below 0.3 mg eq. epicatechin g-1) were obtained in the presence of NaNO2. The maximum antioxidant capacity was observed for thyme honeys (2.2 mg eq. Trolox g-1) followed by honeydew and heather honeys. Individually, only the FC index was able to discriminate between honeydew and blossom honeys, while the other spectroscopic indexes tested allowed the differentiation of some honey types according to the botanical origin. Thus, a holistic treatment of the results was performed using partial least square discriminant analysis (PLS-DA) for classification purposes using FC, TFC, and FRAP results as data. Honeydew and blossom honey were satisfactorily discriminated (error 5%). In addition, blossom honeys can be perfectly classified according to their botanical origin based on two-class PLS-DA classification models.

Engineering Interfacial Environment of Epigallocatechin Gallate Coated Titanium for Next-Generation Bioactive Dental Implant Components.

In view of endowing the surface of abutments, a component of titanium dental implant systems, with antioxidant and antimicrobial properties, a surface layer coated with epigallocatechin gallate (EGCg), a polyphenol belonging to the class of flavonoids, was built on titanium samples. To modulate interfacial properties, EGCg was linked either directly to the surface, or after populating the surface with terminally linked polyethyleneglycol (PEG) chains, Mw ~1600 Da. The underlying assumption is that fouling-resistant, highly hydrated PEG chains could reduce non-specific bioadhesion and magnify intrinsic EGCg properties. Treated surfaces were investigated by a panel of surface/interfacial sensitive techniques, to provide chemico-physical characterization of the surface layer and its interfacial environment. Results show: (i) successful EGCg coupling for both approaches; (ii) that both approaches endow the Ti surface with the same antioxidant properties; (iii) that PEG-EGCg coated surfaces are more hydrophilic and show a significantly higher (>50%) interaction force with water. Obtained results build up a rationale basis for evaluation of the merits of finely tuning interfacial properties of polyphenols coated surfaces in biological tests.

Interactive deciphering electron-shuttling characteristics of Coffea arabica leaves and potential bioenergy-steered anti-SARS-CoV-2 RdRp inhibitor via microbial fuel cells.

Due to the pandemics of COVID-19, herbal medicine has recently been explored for possible antiviral treatment and prevention via novel platform of microbial fuel cells. It was revealed that Coffea arabica leaves was very appropriate for anti-COVID-19 drug development. Antioxidant and anti-inflammatory tests exhibited the most promising activities for C. arabica ethanol extracts and drying approaches were implemented on the leaf samples prior to ethanol extraction. Ethanol extracts of C. arabica leaves were applied to bioenergy evaluation via DC-MFCs, clearly revealing that air-dried leaves (CA-A-EtOH) exhibited the highest bioenergy-stimulating capabilities (ca. 2.72 fold of power amplification to the blank). Furthermore, molecular docking analysis was implemented to decipher the potential of C. arabica leaves metabolites. Chlorogenic acid (-6.5 kcal/mol) owned the highest binding affinity with RdRp of SARS-CoV-2, showing a much lower average RMSF value than an apoprotein. This study suggested C. arabica leaves as an encouraging medicinal herb against SARS-CoV-2.

Hyperglycemia enhances the generation of ROS and RNS that impair antioxidant power and cause oxidative damage in human erythrocytes.

Hyperglycemia is a state in which excess glucose circulates in blood. Erythrocytes are in direct contact with this high glucose concentration and are greatly affected by it. We have examined the effect of hyperglycemic condition on isolated human erythrocytes under in vitro conditions. Erythrocytes were incubated with different concentrations of glucose (5, 15, 30, 45 mmol/L) for 24 h, and several biochemical parameters were determined. Treatment with high glucose concentrations increased heme degradation and methemoglobin level, while methemoglobin reductase activity was decreased. A significant increase in protein oxidation and lipid hydroperoxides with a decrease in total sulfhydryl content was seen. This suggested the generation of oxidative stress, which was confirmed by an enhanced production of reactive oxygen and nitrogen species. Hyperglycemia led to a significant decline in the antioxidant power of erythrocytes, lowering their ability to quench free radicals and reduce metal ions to lower oxidation states. The plasma membrane redox system was upregulated, while ascorbate free radical reductase activity was lowered. Glucose exposure inhibited the enzymes of glycolysis and hexose monophosphate shunt. Electron microscopy showed morphological changes resulting in the formation of echinocytes. Thus, the hyperglycemic condition generates reactive species that oxidize proteins, hemoglobin, and lipids; impair the total antioxidant capacity; and alter morphology in human erythrocytes.