Screening Of Antioxidant Capacity Research Articles

Screening of antioxidant capacity of Nepali medicinal plants with a novel singlet oxygen scavenging assay.

The online version contains supplementary material available at 10.1007/s10068-022-01175-z.

Selected fungi of the genus Lactarius - screening of antioxidant capacity, antimicrobial activity, and genotoxicity

ABSTRACT It is well-known that mushrooms of the genus Lactarius constitute a natural food resource providing health benefits as a nutritient. This genus contains 4 mushrooms identified as L. deliciosus, L. volemus, L. sanguifluus, L. semisanguifluus and L. piperatus which were collected in Serbia. The aim of this study aimed was to identify and characterize the content of phenolic compounds and examine the antioxidant potential of 5 wild edible mushrooms. L. sanguifluus contained the highest content of total phenol compounds (75.25 mg gallic acid equivalents (GAE) per g dry extract weight (GAE/g DE) and exhibited the greatest antioxidant activity through the ability to remove radicals as evidenced by ABTS assay (8.99 mg of trolox equivalents (TE) per g dry extract weight (mg TE/g DE); total reducing power (TRP) assay mg ascorbic acid equivalents per mg of dry extract weight (0.42 mg AAE/g DE) and CUPRAC (14.23 mg TE /g DE). L. deliciosus methanolic extract produced greatest scavenging of the DPPH radical (46%). The methanol mushroom extracts were screened for in vitro antimicrobial activity against a panel of pathogenic bacterial strains using the microdilution method. Of all the extracts tested, L. sanguifluus extract showed the best antibacterial properties. The cytokinesis block micronucleus assay results for the examined mushrooms demonstrated that extracts at a concentration of 3 μg/ml decreased the number of micronuclei (MN) in the range of 19–49% which is significant bearing in mind that radioprotectant amifostine reduced the frequency of MN by only 16.3%. Data thus demonstrate that the 5 wild edible mushrooms of genus Lactarius contain constituents that are beneficial not only as nutrients but also have the potential as antioxidants, antibacterial and antigenotoxic properties.

Metabolomics and biochemical analyses revealed metabolites important for the antioxidant properties of purple glutinous rice

Glutinous rice can be applied to many fields including brewing industry, medicine, cosmetics and food processing. However, we know very little about the basic metabolite information of glutinous rice. In this study, we identified the phenol and flavonoid metabolites in purple glutinous rice and white glutinous rice, and elucidated the relationship between metabolites and total antioxidant capacity. The results demonstrated that flavonoids contents, oligomeric proanthocyanidin contents and total antioxidant capacity of purple glutinous rice were significantly higher than those of white glutinous rice. We identified 390 differential metabolites between the purple glutinous rice and white glutinous rice by LC–MS metabolomics. Correlation analysis results showed that flavonoid and phenol metabolites contents were strongly correlated with total antioxidant capacity. This study further clarified that the pantothenic acid, pebrellin, l-glutamic acid, eupatilin, diosmin, and diosmetin could be used as candidate metabolite markers for antioxidant capacity screening in glutinous rice grains.

Screening of Antioxidant Capacity, Anti-Inflammatory Activity, Anti-Bacterial Activity, And Phytochemical Constituents of Mangosteen Extract (Garcinia Mangostana)

Screening of Antioxidant Capacity, Anti-Inflammatory Activity, Anti-Bacterial Activity, And Phytochemical Constituents of Mangosteen Extract (Garcinia Mangostana)

Review—Monitoring of Endogenous Antioxidants: An Electroanalytical Approach

Electrochemical sensors have attracted much attention for the quantification of various antioxidants in the recent times. Voltammetric methods are highly selective and sensitive tool for the determination of different antioxidants in biological samples at very low concentration. Antioxidant acts as a defence mechanism in a body against various pathogens. Electrochemical techniques are being applied for the screening of antioxidant capacity. These methods are rapid, reliable and simple for the analysis of compounds. Antioxidant compounds are reducing agents and can be easily oxidized on inert electrodes. The present review article summarizes the voltammetric detection of various endogenous antioxidant compounds reported during the last five years.

Optimization of ABTS radical cation assay specifically for determination of antioxidant capacity of intracellular extracts of microalgae and cyanobacteria

A renewed interest in antioxidants has arisen in recent years; microalgae and cyanobacteria are potential sources thereof for use as food/feed ingredients. However, improved methods for comprehensive screening of antioxidant capacity specifically in intracellular extracts of marine microorganisms are required – encompassing lipophilic and hydrophilic compounds simultaneously. The original ABTS method was thus improved, and in particular the procedures of cell disruption and storage were optimized. The best solvent found was ethanol/water (1:1, v/v). The reaction to form ABTS+ in said solvent was essentially complete by eight hours, and this radical cation was stable for at least 6days; at room temperature, the ABTS+ solution remained within an allowable analytical range for up to 13h. Ultra Turrax was the best cell disruption method, and refrigeration was the best preservation method. This improved methodology was validated with four representative strains that respond poorly to cell disruption.

Microfluidics for Monitoring Oxidative Stress and Antioxidant Capacity

The introduction of instrumentation based on microfluidic technologies has revolutionised many areas of life sciences, including genomics and proteomics amongst others. As the role of reactive oxygen species has more recently been linked to an important number of pathologies, such as cancer or cardiovascular disease, this particular field of study has not been the exception in adopting these new technologies. Added interest has been generated thanks to the high compatibility of reactive oxygen species detection techniques in microfluidic devices and previously established ones e.g. fluorescence or electrochemistry. Moreover, innovation in the field has generated devices capable of detecting the state denominated oxidative stress (in vivo), produced by an unbalance between the production of reactive oxygen species and intrinsic antioxidant mechanisms, as well as assessing the capacity of other endogenous molecules to counter the harmful effects of these species. This review has focused on how miniaturisation enabled by microtechnologies and the understanding of microfluidics has offered researchers a unique insight into the cellular processes involving the production of reactive oxygen species in the cellular metabolism, as well as providing a tool for antioxidant capacity screening of compounds. Keywords: Oxidative Stress, Antioxidant Capacity Determination, Lab-On-A-Chip, Drug Screening, Capillary Electrophoresis

Rapid antioxidant capacity screening in herbal extracts using a simple flow injection-spectrophotometric system

A simple flow injection (FI)-spectrophotometric system for the screening of antioxidant capacity in herbal extracts was developed. The analysis was based on the color disappearance due to the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical by antioxidant compounds. DPPH and ascorbic acid were used as reagent and antioxidant standard, respectively. Effects of the DPPH concentration, DPPH flow rate, and reaction coil length on sensitivity were studied. The optimized condition provided the linear range of 0.010–0.300mM ascorbic acid with less than 5%RSD(n=10). Detection limit and quantitation limit were 0.004 and 0.013mM, respectively. Comparison of antioxidant capacity in some herbal extracts determined by the FI system and a standard method was carried out and no significant difference was obtained.

Rapid electrochemical screening of antioxidant capacity (RESAC) of selected tea samples

Antioxidants found in the daily diets behave as chemopreventive agents to inactivate potentially harmful reactive oxygen species present in our organisms. Consequently, it will be quite important to have easy-to-use diagnostic tools to dose antioxidant food ingredients. A method for a robust and rapid electrochemical screening of antioxidant capacity (RESAC) has been developed. To assess the suitability of the developed testing method, different tea varieties were evaluated for their antioxidant capacity. Results obtained with the RESAC method were highly correlated with conventional photometric antioxidant assay like FRAP (0.9457) and DPPH (0.9511). The newly developed RESAC method is easy to use, fast and at a low price. This method is well suited for quality control and may facilitate future studies regarding alteration of antioxidant capacity during growth, storage and processing of food or medicinal plants.

Thin-film organic photodiodes for integrated on-chip chemiluminescence detection – application to antioxidant capacity screening

We demonstrate that solution processed thin-film organic photodiodes (OPDs) can be used as compact and sensitive integrated detectors for antioxidant capacity screening. The OPDs were fabricated with blends of regioregular poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C 61 butyric-acid methyl-ester (PCBM). The devices had a broadband photoresponse from 350 nm to 650 nm with a peak responsivity of 0.25 A/W at 550 nm and a dark current density of 0.59 μA/cm 2 under 10 mV bias for a device area of 1 mm 2. The signal rise and fall times of the detectors were 0.51 μs and 0.66 μs, respectively. The detectors were applied to an on-chip peroxyoxalate chemiluminescence (PO-CL) assay for antioxidant capacity determination. Antioxidant standards were injected into a stream of PO-CL reagents, resulting in a CL emission decrease that correlated with the antioxidant capacity. For the encountered CL signals the OPDs provided a comparable response to photomultiplier tubes (PMTs) commonly used in analytical applications. Antioxidant capacity screening results showed excellent consistency between the two detection methods. The compact and portable detection system is suited not only to low-cost in-the-field antioxidant capacity screening, but could have wider applications for chemiluminescence based diagnostic tests at the point-of-care.

Rapid electrochemical method to screen antioxidative capacity of biological matrices (RESAC)

One aspect involved in initiation and development of cardiovascular diseases and cancers are oxidative processes, leading to the generation of hydroxyl radicals and peroxyl compounds [1]. There is growing body of evidence that the chemopreventive effects of antioxidants contribute to inactivate „reactive oxygen species“ [2–4]. In all cases, assessment of antioxidant capacity of our food or other biological matrices is of utmost importance. The majority of free radicals are good oxidants. Therefore, a good antioxidant maybe at first a reductant. The wide mixture of antioxidants with varying redox potentials in plant foods may interact in a synergistic manner, enabling effective protection against oxidation at low concentration levels [5]. Measurement of electrochemical oxidizability should be an appropriate method to assess antioxidant capacity of a biological sample. The aim of the present study was to apply a recently developed electrochemical method for a rapid screening of antioxidant capacity (RESAC) of biological matrices. The electrochemical detector used was equipped with a glassy carbon electrode, operating at a potential of +600 mV. Calibration of the electrochemical method with common photometric standard methods DPPH [6] and FRAP [7] has been done. Results obtained indicate a good correlation between RESAC and these conventional photometric methods (DPPH r=0,935, n=12; FRAP r=0,992, n=12). After calibration, applicability of the method has been shown with selected tea and green coffee samples. The RESAC-method is a rapid and convenient assay based on electrochemical oxidation for the assessment of antioxidant capacity. The method is well suited for quality and specification control and may facilitate future studies regarding alteration of antioxidant capacity during growth, storage and processing of food or medicinal plants.

A microfluidic system for evaluation of antioxidant capacity based on a peroxyoxalate chemiluminescence assay

A microfluidic system incorporating chemiluminescence detection is reported as a new tool for measuring antioxidant capacity. The detection is based on a peroxyoxalate chemiluminescence (PO-CL) assay with 9,10-bis-(phenylethynyl)anthracene (BPEA) as the fluorescent probe and hydrogen peroxide as the oxidant. Antioxidant plugs injected into the hydrogen peroxide stream result in inhibition of the CL emission which can be quantified and correlated with antioxidant capacity. The PO-CL assay is performed in 800-microm-wide and 800-microm-deep microchannels on a poly(dimethylsiloxane) (PDMS) microchip. Controlled injection of the antioxidant plugs is performed through an injection valve. Of the plant-food based antioxidants tested, beta-carotene was found to be the most efficient hydrogen peroxide scavenger (SAHP of 3.27x10(-3) micromol-1 L), followed by alpha-tocopherol (SAHP of 2.36x10(-3) micromol-1 L) and quercetin (SAHP of 0.31x10(-3) micromol-1 L). Although the method is inherently simple and rapid, excellent analytical performance is afforded in terms of sensitivity, dynamic range, and precision, with RSD values typically below 1.5%. We expect our microfluidic devices to be used for in-the-field antioxidant capacity screening of plant-sourced food and pharmaceutical supplements.

Antioxidant evaluation protocols: Food quality or health effects

Increasing research on natural antioxidants in foods and development of new assays has prompted critical reflection on the field. It has been common practice to identify health benefits from antioxidant activity on the cellular level with antioxidant capacity of food measured in vitro. The use of antioxidants and their positive effects on food quality has been demonstrated in a large variety of foods and beverages using various methods for detection of lipid and protein oxidation or various assays based on electron transfer or hydrogen-atom transfer. A direct positive effect on markers of oxidative status after dietary intervention has, however, been difficult to confirm and much has still to be learnt about antioxidant action in vivo including synergistic or inhibitory roles, the uptake, biotransformation, and tissue distribution of potential antioxidants. This review critically evaluates various types of assays for antioxidative capacity, i.e. the stoichiometry, and antioxidative activity, i.e. the kinetics of the antioxidant action, with focus on the antioxidant mechanism of natural dietary antioxidants, particularly phenolic compounds, on lipid oxidation. It is concluded that it is difficult to transfer antioxidant mechanisms established in model systems and in foods to the in vivo situation and that no simple relationship has been recognized so far between antioxidant capacity determined for various foods and beverages and health benefits for humans. Screening of antioxidant capacity using simple assays in order to predict positive health effects of food are not scientifically justified. Different protocols will have to be used for evaluation of the protection of food by antioxidants and for evaluation of the health effect of antioxidants.

Fluorescence screening of antioxidant capacity in pumpkin seed oils and other natural oils

AbstractPlant oils provide a rich source of dietary polyunsaturated fatty acids (PUFAs) and mostly lipophilic antioxidants. PUFAs are both in their free form and as components of glycerolipids preferred targets of free radical‐induced oxidation, leading to the formation of highly atherogenic compounds. Thus, stabilization of polyunsaturated lipids by radical scavengers in the oils is important in order to avoid pathophysiological side effects of these essential components of our diet. To determine lipid oxidizability and its inhibition by endogenous antioxidants, we developed a simple fluorescence technique. It is based on solubilisation of the oils in aqueous buffer, labeling of the resulting emulsions with a suitable reporter fluorophore, which reflects lipid oxidation, and continuous monitoring of the decomposition process. Using this method, we found that oxidizability of the oils depended only to a limited extent on the content of lipophilic antioxidants. In addition, a smaller fraction of polar (phenolic) compounds showed comparable protective effects, especially in pumpkin seed oil, which is a non‐refined product therefore containing antioxidative components that are removed from most other edible oils during processing. Therefore, the contribution of these “minor” compounds has to be taken into account when potential biological effects of plant oils are evaluated.

High-throughput fluorescence screening of antioxidant capacity in human serum. Effects of dietary flavonoids on lipid and protein oxidation

High-throughput fluorescence screening of antioxidant capacity in human serum. Effects of dietary flavonoids on lipid and protein oxidation