Antioxidant properties of tea investigated by EPR spectroscopy

Visible light triggers the formation of reactive oxygen species in monoclonal antibody formulations

Most monoclonal antibody formulations require the presence of a surfactant, such as polysorbate, to ensure protein stability. The presence of high concentrations of polysorbate have been shown to enhance photooxidation of certain protein drug products when exposed to visible light. The current literature, however, suggest that photooxidation of polysorbate only occurs when exposed to visible light in combination with UVA light. This is probable as peroxides present in polysorbate solutions can be cleaved homolytically in the UVA region. In the visible region, photooxidation is not expected to occur as cleavage of peroxides is not expected at these wavelengths. This report presents findings suggesting that the presence of one or more photosensitiser(s) in polysorbate must be a cause and is required to catalyse the aerobic oxidation of polysorbate solutions upon exposure to visible light. Our investigation aimed to clarify the mechanism(s) of polysorbate photooxidation and explore the kinetics and the identity of the generated radicals and their impact on monoclonal antibody (mAb) degradation. Our study reveals that when polysorbate solutions are exposed to visible light between 400 - 800 nm in the absence of proteins, discolouration, radical formation, and oxygen depletion occur. We discuss the initial formation of reactive species, most likely occurring directly after reaction of molecular oxygen, with the presence of a triplet state photosensitiser, which is generated by intersystem crossing of the excited singlet state. When comparing the photooxidation of PS20 and PS80 in varying quality grades, we propose that singlet oxygen possesses potential for reacting with unsaturated fatty acids in PS80HP, however, PS20HP itself exhibited no measurable oxidation under the tested conditions. The study's final part delves into the photooxidation behaviour of different PS grades, examining its influence on the integrity of a mAb in the formulation. Finally, we examined the effect of photooxidation on the integrity of monoclonal antibodies. Our findings show that the exposure to visible light in polysorbate-containing mAb solutions at high PS concentrations of 4 mg·ml-1 results in increased monoclonal antibody degradation, highlighting the need for cautious evaluation of the correct PS concentration to stabilise protein therapeutics.

Zinc oxide nanoparticles influence on plant tolerance to salinity stress: insights into physiological, biochemical, and molecular responses

A slight variation in ecological milieu of plants, like drought, heavy metal toxicity, abrupt changes in temperature, flood, and salt stress disturbs the usual homeostasis or metabolism in plants. Among these stresses, salinity stress is particularly detrimental to the plants, leading to toxic effects and reduce crop productivity. In a saline environment, the accumulation of sodium and chloride ions up to toxic levels significantly correlates with intracellular osmotic pressure, and can result in morphological, physiological, and molecular alterations in plants. Increased soil salinity triggers salt stress signals that activate various cellular-subcellular mechanisms in plants to enable their survival in saline conditions. Plants can adapt saline conditions by maintaining ion homeostasis, activating osmotic stress pathways, modulating phytohormone signaling, regulating cytoskeleton dynamics, and maintaining cell wall integrity. To address ionic toxicity, researchers from diverse disciplines have explored novel approaches to support plant growth and enhance their resilience. One such approach is the application of nanoparticles as a foliar spray or seed priming agents positively improve the crop quality and yield by activating germination enzymes, maintaining reactive oxygen species homeostasis, promoting synthesis of compatible solutes, stimulating antioxidant defense mechanisms, and facilitating the formation of aquaporins in seeds and root cells for efficient water absorption under various abiotic stresses. Thus, the assessment mainly targets to provide an outline of the impact of salinity stress on plant metabolism and the resistance strategies employed by plants. Additionally, the review also summarized recent research efforts exploring the innovative applications of zinc oxide nanoparticles for reducing salt stress at biochemical, physiological, and molecular levels.

Accessing Properties of Molecular Compounds Involved in Cellular Metabolic Processes with Electron Paramagnetic Resonance, Raman Spectroscopy, and Differential Scanning Calorimetry

In this work, we review some physical methods of macroscopic experiments, which have been recently argued to be promising for the acquisition of valuable characteristics of biomolecular structures and interactions. The methods we focused on are electron paramagnetic resonance spectroscopy, Raman spectroscopy, and differential scanning calorimetry. They were chosen since it can be shown that they are able to provide a mutually complementary picture of the composition of cellular envelopes (with special attention paid to mycobacteria), transitions between their molecular patterning, and the response to biologically active substances (reactive oxygen species and their antagonists-antioxidants-as considered in our case study).

Regulation of Reactive Oxygen Species during Salt Stress in Plants and Their Crosstalk with Other Signaling Molecules-Current Perspectives and Future Directions

Salt stress is a severe type of environmental stress. It adversely affects agricultural production worldwide. The overproduction of reactive oxygen species (ROS) is the most frequent phenomenon during salt stress. ROS are extremely reactive and, in high amounts, noxious, leading to destructive processes and causing cellular damage. However, at lower concentrations, ROS function as secondary messengers, playing a critical role as signaling molecules, ensuring regulation of growth and adjustment to multifactorial stresses. Plants contain several enzymatic and non-enzymatic antioxidants that can detoxify ROS. The production of ROS and their scavenging are important aspects of the plant's normal response to adverse conditions. Recently, this field has attracted immense attention from plant scientists; however, ROS-induced signaling pathways during salt stress remain largely unknown. In this review, we will discuss the critical role of different antioxidants in salt stress tolerance. We also summarize the recent advances on the detrimental effects of ROS, on the antioxidant machinery scavenging ROS under salt stress, and on the crosstalk between ROS and other various signaling molecules, including nitric oxide, hydrogen sulfide, calcium, and phytohormones. Moreover, the utilization of "-omic" approaches to improve the ROS-regulating antioxidant system during the adaptation process to salt stress is also described.

Effects of ultrasound pretreatment assisted drying methods on drying characteristics, physical and bioactive properties of windfall apples

BACKGROUND

Drying is one of the most important post-harvest processes in order to ensure that the products harvested in certain periods are consumed throughout the year. In this study, Golden Delicious, Oregon Spur and Granny Smith apple cultivars (fallen apples) were dried in open-sun, a controlled glasshouse, microwave oven (200 W), hybrid system (100 W + 60 °C), convective greenhouse (70 °C) and freeze-dryer (-55 °C) with and without ultrasound pretreatments.

RESULTS

Present findings revealed that the longest drying duration was observed in freeze-drying and the shortest in microwave drying. The greatest color change (ΔE) was observed in ultrasound pretreated Oregon Spur apples dried in a controlled glasshouse. The greatest total phenolics (40.08 mg GAE g^-1 ), DPPH (2,2-diphenyl-1-picrylhydrazyl) inhibition activity (46.96%), FRAP (ferric reducing ability of plasma) antioxidant activity (68.01 μg Trolox g^-1 ) and ascorbic acid content (1.52 mg AAE g^-1 ) were observed in open sun-dried Granny Smith apples without ultrasound pretreatment.

CONCLUSIONS

Generally, microwave and hybrid drying yielded better outcomes for bioactive, HMF (5-hydroxymethyl-2-furfural) and drying characteristics of windfall apples. © 2022 Society of Chemical Industry.

Protein photodegradation in the visible range? Insights into protein photooxidation with respect to protein concentration

Visible light (400-800 nm) can lead to photooxidation of protein formulations, which might impair protein integrity. However, the relevant mechanism of photooxidation upon visible light exposure is still unclear for therapeutic proteins, since proteinogenic structures do not absorb light in the visible range. Here, we show that exposure of monoclonal antibody formulations to visible light, lead to the formation of reactive oxygen species (ROS), which subsequently induce specific protein degradations. The formation of ROS and singlet oxygen upon visible light exposure is investigated using electron paramagnetic resonance (EPR) spectroscopy. We describe the initial formation of ROS, most likely after direct reaction of molecular oxygen with a triplet state photosensitizer, generated from intersystem crossing of the excited singlet state. Since these radicals affect the oxygen content in the headspace of the vial, we monitored photooxidation of these mAb formulations. With increasing protein concentrations, we found (i) a decreasing headspace oxygen content in the sample, (ii) a higher relative number of radicals in solution and (iii) a higher protein degradation. Thus, the protein concentration dependence indicates the presence of higher concentration of a currently unknown photosensitizer.

Facile Detection of Light-Controlled Radical Scavengers from Natural Products Using In Situ UV-LED NMR Spectroscopy

With the recent development of chemical analysis technology, attention has been placed on natural light-sensitive compounds that exhibit photoreactivity to expand the structural diversity of natural product chemistry. Photochemical reactions that proceed via a free radical mechanism could be used to modulate the radical-scavenging ability of natural products as well as involve structural change. As the health benefits of radicals are also presented, there is a need for a controllable radical scavenging method for topical and selective application. In this study, we developed a novel acquisition and processing method to identify light-controlled radical scavengers in plant extracts and evaluate their antioxidant activity under light irradiation based on in situ UV-LED NMR spectroscopy. Using the developed method, licochalcones A and B, in which the trans and cis isomers undergo reversible photoisomerization, were selectively identified from licorice root extract, and their light-induced free radical scavenging activity was confirmed.

Cardioprotective Role of Theobroma cacao against Isoproterenol-Induced Acute Myocardial Injury

BACKGROUND

Antioxidants are beneficial in myocardial infarction (MI). It is suggestive that Theobroma cacao (TC) with rich antioxidant properties can be of health benefits in myocardial injury.

AIM

The study investigated the effect of Theobroma cacao on cardioprotection in isoproterenol-induced myocardial infarction in rats.

MATERIAL AND METHODS

Male Wistar rats divided into four groups of 6 rats were used for the study. In group 1, 0.9% normal saline placebo was administered via oral gavage to the control. Group 2 was the MI induced group that was given 100 mg/kg body weight isoproterenol subcutaneously twice at an interval of 24 hours. Group 3 was administered TC for 2 weeks at 100 mg/kg bodyweight via the oral route. Group 4 was pretreated with TC (100 mg/kg) via oral route for 2 weeks, immediately followed by the administration of 100 mg/kg body weight isoproterenol subcutaneously twice at an interval of 24 hours. The rats were sacrificed using chloroform anesthesia, and blood samples collected via cardiac puncture. The serum was analyzed for troponin level, lactate dehydrogenase (LDH), and malondialdehyde (MDA) level.

RESULTS

The serum troponin, LDH, and MDA levels were found to be significantly (p<0.01) increased in the MI group compared with the control. Pretreatment with TC before MI induction significantly (p<0.01) prevented increased serum troponin, LDH, and MDA levels when compared with the MI group. There was also a significant (p<0.01) decrease in MDA in the TC group compared with the control.

CONCLUSION

These results suggest that Theobroma cacao protects against isoproterenol-induced myocardial injury, possibly by preventing oxidative stress and consequent lipid peroxidation.

Influence of Ultrasound and the Conditions of Convective Drying with Dehumidified Air on the Course of the Process and Selected Properties of Apple Tissue

The conditions of convective drying induce a negative effect on the quality of the dried products, and thus, innovative solutions, such as the utilization of ultrasound and dehumidified air are gaining importance. Therefore, the aim of this study was to evaluate the impact of ultrasound pretreatment and variable air temperature on the kinetics of convective drying with dehumidified air and the quality of dried apples. Apples were dried with dehumidified and non-dehumidified air at 55, 70 and 85 °C. Preliminary ultrasound treatment was conducted by immersion for 60 min. The effect of both ultrasound and dehumidified air utilization was more prominent in the terms of drying time reduction, when lower drying temperatures were used. Drying of apples with dehumidified air, preceded by ultrasound pretreatment, resulted in a greater rehydration capacity of the products, and limited the browning process. Dehumidified air increased the lightness of the dried products, while sonication darkened them. The use of ultrasound before drying coupled with a drying with dehumidified medium at a temperature of 70 °C reduced the exposure of the product to a high temperature and oxygen. Products treated before dehumidified air drying with ultrasounds were characterized by high total phenolic content and the greatest antioxidant activity. This was because such technological treatment reduced exposure of the product to a high temperature and oxygen.

Oxidative stress in oocyte aging and female reproduction

In a healthy body, reactive oxygen species (ROS) and antioxidants remain balanced. When the balance is broken toward an overabundance of ROS, oxidative stress appears and may lead to oocyte aging. Oocyte aging is mainly reflected as the gradual decrease of oocyte quantity and quality. Here, we aim to review the relationship between oxidative stress and oocyte aging. First, we introduced that the defective mitochondria, the age-related ovarian aging, the repeated ovulation, and the high-oxygen environment were the ovarian sources of ROS in vivo and in vitro. And we also introduced other sources of ROS accumulation in ovaries, such as overweight and unhealthy lifestyles. Then, we figured that oxidative stress may act as the "initiator" for oocyte aging and reproductive pathology, which specifically causes follicular abnormally atresia, abnormal meiosis, lower fertilization rate, delayed embryonic development, and reproductive disease, including polycystic ovary syndrome and ovary endometriosis cyst. Finally, we discussed current strategies for delaying oocyte aging. We introduced three autophagy antioxidant pathways like Beclin-VPS34-Atg14, adenosine 5'-monophosphate (AMP)-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR), and p62-Keap1-Nrf2. And we also describe the different antioxidants used to combat oocyte aging. In addition, the hypoxic (5% O₂ ) culture environment for oocytes avoiding oxidative stress in vitro. So, this review not only contribute to our general understanding of oxidative stress and oocyte aging but also lay the foundations for the therapies to treat premature ovarian failure and oocyte aging in women.

Effect of microorganisms on the fingerprint of the volatile compounds in pine nut (Pinus koraiensis) peptide powder during storage

Pine nut (Pinus koraiensis) peptide (PNP) powder possesses promising bioactivities. However, the powder may have the quality problem of becoming sticky and smelly. Therefore, the volatile compounds' fingerprint of PNP powder was established by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The essential spoilage microorganisms were confirmed by 16S rDNA amplicon sequencing. The antioxidant activity, which presents PNP powder's quality, decreased during storage with the highest value of (1.88 ± 0.18) × 10¹⁴ at day 30. Fifty-nine significantly changed signals were detected; eight compounds were considered as volatile marker compounds. Besides, Firmicutes and Cyanobacteria were the essential spoilage microorganisms in PNP powder at the phylum level. Significantly, unidentified_Chloroplast, which belongs to Cyanobacteria, had a positive correlation with volatile marker compounds. The results proved that microorganisms indeed affect volatile compounds of PNP powder and induced off-flavor, including hexanal, which can be used as the detection indicator for the quality control of PNP powder. PRACTICAL APPLICATIONS: In the present study, we controlled the influence of moisture migration on PNP powder and investigated microorganisms' effects on volatile compounds of PNP powder. HS-GC-IMS could be used to establish fingerprints of volatile compounds in PNP powder. 16S rDNA amplicon sequencing method could be used to screen the dominant spoilage bacteria in PNP powder and established essential spoilage microorganisms of PNP powder. This work provides a reference for category identification of PNP powder, which was infected by spoilage bacteria or not, and stored at day 0 or 30 days. Hexanal can be considered as the volatile marker compound generated from microorganisms. It helps to realize the controllability of PNP powder storage and prolongs the shelf life of PNP powder.

Impact of seed color and storage time on the radish seed germination and sprout growth in plasma agriculture

The use of low-temperature plasma for the pre-sowing seed treatment is still in the early stage of research; thus, numerous factors affecting germination percentage, seedling growth, and yield remains unknown. This study aimed to estimate how two critical factors, such as harvest year and seed coat color, affect the percentage of germination and seedling growth after plasma treatment. Radish seeds stored for 2 and 1 year after harvesting (harvested in 2017 and 2018) were sorted into two colors (brown and grey) to investigate the plasma effect on harvest year and seed coat color. We analyzed the amounts of seed phytohormones and antioxidant (γ-tocopherol) were analyzed using mass spectrometry, and physical changes were studied using SEM, EDX, and EPR to understand the mechanism of plasma-induced changes in radish seeds. The obtained results revealed that plasma treatment on seeds affects the germination kinetics, and the maximal germination percentage depends on seed color and the time of seed storage after harvest. Through this study, for the first time, we demonstrated that physical and chemical changes in radish seeds after plasma treatment depends upon the seed color and harvest year. Positive effects of plasma treatment on growth are stronger for sprouts from seeds harvested in 2017 than in 2018. The plasma treatment effect on the sprouts germinated from grey seeds effect was stronger than sprouts from brown radish seeds. The amounts of gibberellin A3 and abscisic acid in control seeds strongly depended on the seed color, and plasma induced changes were better in grey seeds harvested in 2017. Therefore, this study reveals that Air scalar-DBD plasma's reactive oxygen and nitrogen species (RONS) can efficiently accelerate germination and growth in older seeds.

Improving Antioxidant Activity of β-Lactoglobulin by Nature-Inspired Conjugation with Gentisic Acid

Dietary phenolic compounds display strong antioxidant capabilities but face limited practical applications as a result of their poor biocompatibility (high immune resistance). Some food proteins possess mild antioxidant capabilities but are often not sufficient to maintain a reactive oxidative species balance. In this study, we overcome these barriers by covalently conjugating a natural phenolic antioxidant, gentisic acid (GA), onto an antioxidant protein, β-lactoglobulin (βLG). Upon optimization of conjugation conditions, we confirm the formation of βLG-GA conjugates with mass spectrometry, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption. Surface charge analysis revealed a saturation molar ratio of 150:1 (GA/βLG), while far-ultraviolet circular dichroism revealed substantial changes in the protein secondary structure upon conjugation. The antioxidant capability of resultant conjugates was probed by monitoring the decay of 1,1-diphenyl-2-picrylhydrazyl radical content via time-resolved electron paramagnetic resonance spectroscopy, which suggested two possible pathways to scavenge radicals, i.e., the antioxidant GA on the protein surface and the protein conformational change that exposes more antioxidant amino acids. To our best knowledge, this work is the first report on the fabrication of a dual-effect antioxidant biopolymer using a nature-inspired template via covalent linking with the antioxidant mechanism probed. Our findings are essential for opening a new route to design functional materials with enhanced antioxidant activity and biocompatibility.

Curcuma longa extracts suppress pathophysiology of experimental hepatic parenchymal cell necrosis

The study sought to investigate the protective potentials of Curcuma longa rhizome following potassium bromate-induced liver injury in Wistar rats. Thirty-five male Wistar rats were divided into 7 groups of 5 rats each (n = 5). Control group received normal saline while the other groups received oral administration of 100 mg/kg potassium bromate daily for two weeks to induce hepatic injury. Negative control I rats were sacrificed immediately after induction of hepatic injury, while the test groups were given oral dose of ethanol extract of Curcuma longa rhizome (EECLOR) at 100, 200 and 400 mg/kg for two weeks. Positive control group was treated with Silymarin for two weeks, while negative control II group was observed for the two-week period. At the end of the study, serum biochemical parameters of liver function enzymes, malondialdehyde and histopathological changes were investigated. Necrotic hepatocytes were quantified in H&E-stained liver sections using the morphologic criteria of typical necrotic tissue. Hepatocytes that remained intact were identified as those with round euchromatic nuclei with prominent nucleoli. Histological examination and morphological grading of the stained sections showed massive necrosis across the zones. EECLOR improved liver functions evidenced by reduced activity of serum amino transferases. It also reduced lipid peroxidation. In addition, there was significant reduction of hepatocytes showing morphological criteria of necrosis in EECLOR-treated rats across the zones, with appreciable radial sinusoidal arrangement. In conclusion, the protective actions of EECLOR against potassium bromate liver toxicity in rats, appears to be due to its ability to reduce lipid peroxidation.

Gamma irradiation of clove: level of trapped radicals and effects on bioactive composition

BACKGROUND

Food irradiation is a widely used technique for improving the safety and shelf life of foods, including most spices. However, growing concerns by consumers about this technique require further investigation on the effects of radiation, both on the safety of the food and on its organoleptic properties. In this work, cloves of diverse origins were submitted to different irradiation doses in a ⁶⁰ Co source. The presence of trapped radicals and their time-dependent decay after irradiation were assessed by electron spin resonance (ESR) spectroscopy. The volatile bioactive composition and the clove oil were evaluated before and after irradiation by gas chromatography time-of-flight mass spectrometry.

RESULTS

Results show an increase of the amount of volatiles collected after irradiation, especially of caryophyllene oxide and acetic acid, although these are still minor constituents. No new compound was detected after irradiation. Radicals decay fast, and 60 days after irradiation they were undetectable by ESR.

CONCLUSION

Gamma irradiation showed to be a clean technique for clove decontamination, since no significant change in the aroma or oil compositions was found, and low levels of trapped paramagnetic species, after the initial decay period, were detected upon irradiation. Furthermore, irradiation doses higher than those legally allowed are equally safe. © 2018 Society of Chemical Industry.

A new dual-peptide strategy for enhancing antioxidant activity and exploring the enhancement mechanism

The development of a new generation antioxidant peptides with high free radical scavenging rates is highly desirable, but remains a great challenge.

Composition Analysis by UPLC-PDA-ESI (-)-HRMS and Antioxidant Activity Using Saccharomyces cerevisiae Model of Herbal Teas and Green Teas from Hainan

Different teas from everywhere are very useful and have been extensively studied. We studied the antioxidant activity of herbal teas and green teas from Hainan, Mallotus oblongifolius Muell. Arg. (MO), Ilex kudingcha C.J. Tseng (KD), Camellia sinensis var. assamica (J. W. Mast.) Kitam. Hainan Dayezhong (DY), and Camellia sinensis (L.) O. Ktze. (produced from Hainan Baisha (BS)). The total phenol content and total flavonoid content from water extracts, resin extracts and fractions of herbal teas and green teas were compared. Later, eight fractions of herbal teas and green teas were subjected to UPLC-PDA-ESI-(-)-HRMS. We determined 1-diphenyl -2-picryl-hydrazyl radical and hydroxyl free radical scavenging activity by electron paramagnetic resonance spectroscopy. We subjected Saccharomyces cerevisiae to hydrogen peroxide, stress and evaluated antioxidant activity of herbal teas and green teas in cellulo. The experiment identified more than 14 potential antioxidant compounds from herbal teas and green teas. The herbal teas and green teas had a clearance rate higher than ferulic acid at the same concentrations. MO best reduced intracellular oxidation levels and increased catalase, glutathione reductase activities, glutathione reduced and glutathione oxidized content. KD had the highest cell survival rate and reduced cell lipid peroxidation. DY best improved superoxide dismutase activity and BS was the most active in the halo test. Therefore, we concluded that MO had stronger antioxidant activity than other herbal teas and green teas from Hainan, especially, which reduce S. cerevisiae oxidative stress under H₂O₂ stress.

Protective role of quercetin against copper(II)-induced oxidative stress: A spectroscopic, theoretical and DNA damage study

The radical scavenging and metal chelating properties of flavonoids indicate that they may play a protective role in diseases with perturbed metal homeostasis such as Alzheimer's disease. In this work we investigated the effect of the coordination of quercetin to copper(II) in view of the formation of ROS in Cu-catalyzed Fenton reaction. ABTS and DPPH assays confirmed that the copper(II)-quercetin complex exhibits a stronger radical scavenging activity than does quercetin alone. EPR spin trapping experiments have shown that chelation of quercetin to copper significantly suppressed the formation of hydroxyl radicals in the Cu(II)-Fenton reaction. DNA damage experiments revealed a protective effect for quercetin, but only at higher stoichiometric ratios of quercetin relative to copper. DNA protective effect of quercetin against ROS attack was described by two mechanisms. The first mechanism lies in suppressed formation of ROS due to the decreased catalytic action of copper in the Fenton reaction, as a consequence of its chelation and direct scavenging of ROS by free quercetin. Since the Cu-quercetin complex intercalates into DNA, the second mechanism was attributed to a suppressed intercalating ability of the Cu-quercetin complex due to the mildly intercalating free quercetin into DNA, thus creating a protective wall against stronger intercalators.

Improving the quality of fermented black tea juice with oolong tea infusion

Fresh tea leaves were crushed into juice and then fermented (oxidation) to obtain fermented black tea juice, which can be used to prepare black tea beverage. The effects of addition of oolong tea infusion or tossing of tea leaves on the sensory quality and theaflavins (TFs) concentration of fermented black tea juice were investigated. The results showed that both addition of tea infusion and tossing of fresh tea leaves increased the TFs/thearubigins (TRs) ratio and improved the sensory quality of fermented black tea juice. The TFs/TRs ratio was found to be significantly correlated with the scores for flavor (r = 0.98), mouth feel (r = 0.94), and overall acceptability (r = 0.91) of the fermented black tea juices from different processes. This result suggested that a relatively high concentration of catechins and stepwise enzymatic oxidation were the crucial factors that increased the TFs/TRs ratio and improved the sensory quality. The combination of adding tea infusion and tossing fresh tea leaves greatly improved the quality of the fermented black tea juice by markedly increasing the TFs/TRs ratio (87%). Results of the present study provided useful information for improving the quality of fermented black tea juice.

A Randomized Controlled Trial of Green Tea Beverages on the in vivo Radical Scavenging Activity in Human Skin

BACKGROUND

Oxidative stress plays an important role in the pathogenesis of various skin diseases. Thus, the antioxidant network of the skin relies on the uptake of exogenous antioxidants to ensure cell protection against radical formation. Green tea is one of the main sources of polyphenolic antioxidant compounds, but only few data are available on its cutaneous antioxidant effects.

METHODS

The radical scavenging properties of Benifuuki and Yabukita green tea were investigated in the human skin. Thirty-two participants who met the inclusion criteria were randomized to consume 3 cups per day of either Benifuuki tea, Yabukita tea, or water (control group) for 2 weeks. Electron paramagnetic resonance (EPR) spectroscopy was applied to measure the radical scavenging capacity of the skin in vivo before and after the intervention.

RESULTS

Both Yabukita and Benifuuki tea led to an increase in the radical scavenging activity of the skin by 28 and 29%, respectively, and the difference was significant when compared to the control group. Benifuuki tea, previously reported to be superior in bioavailability due to a highly absorbable methylated catechin, did not prove to be more effective than the common Yabukita tea.

CONCLUSION

The results show that green tea enhances the radical scavenging capacity of the skin and support the hypothesis that green tea may offer protection against cutaneous oxidative stress.

Structure and dynamics of cetyltrimethylammonium chloride-sodium dodecylsulfate (CTAC-SDS) catanionic vesicles: High-value nano-vehicles from low-cost surfactants

HYPOTHESIS

Catanionic vesicles based on large-scale produced surfactants represent a promising platform for the design of innovative, effective and relatively inexpensive nano-vehicles for a variety of actives. Structural, dynamic and functional behavior of these aggregates is finely tuned by the molecular features of their components and can be opportunely tailored for their applications as drug carriers.

EXPERIMENTS

Here we investigate the aggregates formed by CTAC and SDS, two of the most diffused surfactants, by means of Dynamic Light Scattering, Small Angle Neutron Scattering and Electron Paramagnetic Resonance spectroscopy (EPR). The exploitation of these aggregates as nano-vehicles is explored using the poorly water-soluble antioxidant trans-resveratrol (t-RESV), testing t-RESV solubility and antioxidant activity by means of UV, fluorescence spectroscopy and EPR.

FINDINGS

The presence of a large stability region of catanionic vesicles on the CTAC-rich side of the phase diagram is highlighted and interpreted in terms of the mismatch between the lengths of the surfactant tails and of first reported effects of the chloride counterions. CTAC-SDS vesicles massively solubilize t-RESV, which in catanionic vesicles exerts a potent antioxidant and radical-scavenging activity. This behavior arises from the positioning of the active at the surface of the vesicular aggregates thus being sufficiently exposed to the external medium.

In Vitro Digestibility of Aluminum from Hibiscus sabdariffa Hot Watery Infusion and Its Concentration in Urine of Healthy Individuals

Increased ingestion of aluminum (Al) can lead to its accumulation in the human body, especially in people with kidney problems. Al is also associated with several nervous diseases and its negative influence on embryo development during pregnancy has been proven in animal models. Hibiscus sabdariffa L. petals are widely used alone or in fruit tea formulas, which are recommended for drinking during pregnancy instead of tea. Its petals can contain similar and even higher amounts of Al as tea, which is a known Al accumulator. Our research investigated whether the regular intake of H. sabdariffa infusion leads to increased burden of Al. Sixteen days of ingestion of H. sabdariffa infusion (c _Al = 0.5 mg.L^-1) led to increased but unbalanced levels (15-86 μg L^-1) of Al in urine compared to a period when the infusion was not ingested. The highest amounts of Al excreted were observed every third day during the ingestion. Mild health problems, such as nausea and dizziness (which could be related to plant properties) were reported by more sensitive volunteers.Our results suggest that the tea infusion from H. sabdariffa petals increases body burden of Al and, therefore, sensitive individuals as pregnant women and people with kidney problems should be cautious with excessive consumption of hibiscus infusion or fruit teas containing this plant. However, further study including more individuals is needed to fully confirm our preliminary results.

Antioxidant Capacity: Experimental Determination by EPR Spectroscopy and Mathematical Modeling

A new method of determining antioxidant capacity based on a mathematical model is presented in this paper. The model was fitted to 1000 data points of electron paramagnetic resonance (EPR) spectroscopy measurements of various food product samples such as tea, wine, juice, and herbs with Trolox equivalent antioxidant capacity (TEAC) values from 20 to 2000 μmol TE/100 mL. The proposed mathematical equation allows for a determination of TEAC of food products based on a single EPR spectroscopy measurement. The model was tested on the basis of 80 EPR spectroscopy measurements of herbs, tea, coffee, and juice samples. The proposed model works for both strong and weak antioxidants (TEAC values from 21 to 2347 μmol TE/100 mL). The determination coefficient between TEAC values obtained experimentally and TEAC values calculated with proposed mathematical equation was found to be R(2) = 0.98. Therefore, the proposed new method of TEAC determination based on a mathematical model is a good alternative to the standard EPR method due to its being fast, accurate, inexpensive, and simple to perform.

Tea extracts protect normal lymphocytes but not leukemia cells from UV radiation-induced ROS production: An EPR spin trap study

PURPOSE

An ex vivo method for detection of free radicals and their neutralization by aqueous tea in human normal lymphocytes and MEC-1 leukemia cells under ultraviolet (UV) irradiation was investigated.

MATERIALS AND METHODS

This method is based on the electron paramagnetic resonance (EPR) spectroscopy spin-trapping technique. 5-tert-butoxycarbonyl 5-methyl-1-pyrroline N-oxide (BMPO) was used as the spin trap. Normal human lymphocytes and leukemia cells were exposed to UVB radiation (290-315 nm) at 47.7 and 159 mJ/cm(2) and to UVA radiation (315-400 nm) at 53.7 J/cm(2).

RESULTS

No significant radical production at 47.7 mJ/cm(2) UVB dose in both cell lines was observed. In normal cells, free radical production was observed at 159 mJ/cm(2) UVB and 53.7 J/cm(2) UVA doses. However, both UV sources did not significantly produce free radicals in leukemia cells. A radical scavenging property of tea extracts (black, green, sage, rosehip) was observed in normal lymphocytes after both UVB and UVA exposure. In leukemia cells, the intensities of EPR signals produced in BMPO with tea extracts were found to be increased substantially after UVA exposure.

CONCLUSION

These results showed that UV radiation induced free radical formation in normal human lymphocytes and indicated that tea extracts may be useful as photoprotective agents for them. On the other hand, tea extracts facilitated free radical production in leukemia cells.

Radical scavenging of white tea and its flavonoid constituents by electron paramagnetic resonance (EPR) spectroscopy

White tea (WT) presents high levels of catechins, which are known to reduce oxidative stress. WT is the least processed tea, unfermented and prepared only from very young tea leaves. The subject of this paper is the use of the spin trap method and electron paramagnetic resonance (EPR) spectroscopy as the analytical tool to measure, for the first time, the radical scavenging activity of WT and its major catechin components, epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG), against the methoxy radical, using ferulic acid as antioxidant pattern. The antioxidant activity has been measured by the decrease of the intensity of the spectral bands of the adduct DMPO-OCH3 in the EPR with the amount of antioxidant in the reactive mixture. Tea leaves and buds were extracted with waterless methanol. It has been proved that tea compounds with more antiradical activity against methoxy radical are those with the gallate group, EGCG and ECG.

Protective effect of artichoke (Cynara scolymus) leaf extract against lead toxicity in rat

CONTEXT

Artichoke, Cynara scolymus L. (Asteraceae), has many natural antioxidants and multiple pharmacological actions. Recent studies have shown that it has antitoxic activity.

OBJECTIVE

Lead (Pb) is a dangerous environmental toxicant that induces a broad range of dysfunctions in human. This study evaluated the protective effect of the hydroethanolic extract of artichoke against altered biochemical parameters in rats fed with lead-containing diet.

MATERIALS AND METHODS

Thirty-two rats were randomly divided into four groups. The first (control) group received standard diet. The second, third and fourth groups received 500 mg lead/kg diet, 500 mg lead/kg diet plus 300 mg/kg b.w. artichoke extract daily, and 500 mg lead/kg diet plus 1 mg vitamin C/100 g b.w. daily for 6 weeks, respectively. Serum lead, lipoprotein profile, ALT (alanine transaminase), AST (aspartate transaminase), ALP (alkaline phosphatase), malondialdehyde (MDA) and liver histopathology assessments were conducted.

RESULTS

Serum lead, triglyceride (TG), VLDL, ALT, AST, ALP and MDA levels decreased significantly (p < 0.05) in the artichoke-treated group (35.85, 38.26, 38.38, 21.90, 12.81, 26.86 and 46.91%, respectively) compared to lead-intoxicated rats without treatment. No significant change was observed in serum lead, ALP and ALT between artichoke and vitamin C-treated groups (p > 0.05). Furthermore, the liver histopathology in rats treated with artichoke showed a mild degree of lymphocyte infiltration that was relatively comparable to the control and vitamin C-treated groups.

DISCUSSION AND CONCLUSION

These results clearly show that the artichoke extract in lead-poisoned rats has suitable chelating properties for the reduction of blood lead levels.

A study of the antioxidant properties of beers using electron paramagnetic resonance

The antioxidant properties of various kinds of beers were investigated using electron paramagnetic resonance (EPR) spectroscopy. This was possible by measuring the changes in the intensity of the EPR spectrum that resulted from the interaction of the stable radical DPPH (1,1-diphenyl-2-picrylhydrazyl) with the antioxidants found in a beer sample. The antioxidant capacity was then presented in Trolox Equivalents, e.g. μM trolox in a beer sample of 100ml. The influence of the type, colour, the content of the extract and alcohol on the antioxidant activities of commercial beer samples was investigated using two-way hierarchical clustering and analysis of variance. The results showed that all of the beers investigated exhibit antioxidant properties. By performing an analysis of variance, it was found that the value of the antioxidant capacity significantly (0.05 level of significance) depends on the content of the extract and the colour of the beer. It seems that additives also influence the antioxidant properties to some extent, but neither the alcohol content nor the kind of fermentation affects the antioxidant properties of beer.

Analysis of the inhibition of PAI-1 by metal theaflavin complexes and their degradation products

The inhibition of elements of the plasminogen activator system [urokinase (uPA), tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1)] plays an important role in human diseases. PAI-1 is overexpressed in obesity and diabetes, and the inhibition of this protein has been postulated to alleviate the symptoms of both disorders. We found that two theaflavins (TFs) from black tea inhibit PAI-1 and we suggest that the beneficial effects of drinking tea may be associated with the suppression of PAI-1 activity by theaflavins. Epidemiological studies are controversial; some studies show the beneficial effects of drinking black tea on obesity and diabetes, while others do not. TFs, a family of compounds that can comprise up to 40% the dry weight of black tea, are responsible for the characteristic color, and they are known to chelate metals. We hypothesized that the content/variety of metals present in drinking water may be one of the reasons for such controversies in the population studies. TFs are excellent chelating compounds by trapping metals into complexes; thus, the quality of water used for tea preparation may influence changes in the formation of new products according to TF affinity for different metals, as well as their high molecular weight oxidation products. Our modeling and docking studies suggest that TF/metal complexes have similar affinity to PAI-1 as native TFs. However, analyses using liquid chromatography-mass spectroscopy (LC-MS) revealed the presence of TF degradation products in tea brewed using water containing metal salts. These can further form high molecular weight oxidation products. Thus, metals present in tea could diminish the beneficial effects of black tea by reducing TF concentration via metal-induced degradation and precipitation.

Aluminium and other elements in selected herbal tea plant species and their infusions

The determination of Al, B, Cu, Fe, Mn, Ni, P, Zn and Ca, K, Mg by inductively coupled plasma optical emission spectrometry (ICP-OES) and flame atomic absorption spectroscopy (FAAS), respectively, in digests and infusions of Hibiscus sabdariffa (petals), Rosa canina (receptacles), Ginkgo biloba (leaves), Cymbopogon citratus (leaves), Aloe vera (leaves) and Panax ginseng (roots) was carried out in this study. Particular attention has been given to Al and heavy metals for the identification of possible raw material contaminants, their transformation into the infusion and for predicting their eventual role in the human diet during daily consumption. Additionally, Ion Chromatography (IC) speciation of Al in the leachates was carried out. In dry herbs, hibiscus and ginkgo appeared to contain the greatest contents of Al, Fe, K, Mn, Ni, Zn and B, Mg, P, respectively. A. vera contained the highest amount of Ca and highest values of Cu and P were observed in ginseng. In infusions, the topmost concentrations of Al, B, Cu, Fe, P, K, Mn, Ni, Zn were detected in those prepared from hibiscus petals, Ca from aloe leaves and Mg from leaves of ginkgo. According to a possible daily consumption exceeding 1 L, hibiscus decoction was identified as potentially dietetically significant in the content of certain elements. It seems to be possibly one of the top contributors of B from food (up to 5.5±0.2 mg/L). The Mg contained in the infusion (up to 106±5 mg/L) may be a contributor in the attenuation of blood pressure. A high amount of accessible Mn (up to 17.4±1.1 mg/L) can probably have an adverse effect in humans. The total Al allowance (up to 1.2±0.1 mg/L) suggests that no more than 1 L of the hibiscus infusion should be consumed per day by sensitive individuals including pregnant women and should be completely excluded from the diet of children under 6 months of age and children with chronic renal failure.

EPR spectroscopy as a tool for investigation of differences in radical status in wheat plants of various tolerances to osmotic stress induced by NaCl and PEG-treatment

Two kinds of wheat genotypes with different tolerance to osmotic stress (NaCl and PEG-treatment) were investigated with biochemical analyses, including the measurements of total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and starch content. The results were compared with electron paramagnetic resonance (EPR) data concerning the nature and amounts of stable long lived radicals present in the control and stressed plants. In addition, the changes in manganese content upon stress conditions were monitored. Different mechanisms of protection against PEG stress in sensitive and tolerant wheat genotypes were postulated. In sensitive genotypes, electrons were created in excess in stress conditions, and were stabilized by polysaccharide molecules, whereas in tolerant genotypes, protection by antioxidants dominated. Moreover, the quinone-semiquinone balance shifted towards semiquinone, which became the place of electron trapping. NaCl-treatment yielded significant effects mainly in sensitive genotypes and was connected with the changes of water structure, leading to inactivation of reactive oxygen species by water molecules.

The effect of intra-peritoneal administration of Papaver bracteatum Lindl. extract on development of NMRI mice oocytes treated with Doxorubicin

Purpose

The effect of water-alcohol Papaver bracteatum Lindl. extract on development of mice oocytes treated with Doxorubicin (dox) was examined in this study.

Methods

The mice were classified into four groups. Control group, mice injected intraperitoneally (IP) with saline. Extract group alone, mice treated with 200 mg/kg of body weight (bw), IP, twelve consecutive days. Dox group alone, mice were given dox, IP, 10 mg/kg bw. Experimental group treated with extract and dox together. Effect of the extract on the development of mice oocytes treated with dox were evaluated through assisted reproductive technology techniques (ARTs).

Results

Developmental rate and blastocyst formation was improved by using the extract. A significant increase in in vitro developmental competence in comparison with dox group (P < 0.05) was observed.

Conclusions

The results of this study indicated that P. bracteatum Lindl. extract could prevent dox toxicity of dox affecting both follicle or oocytes, and therefore it can result in improved embryo development which was observed in mice treated with dox plus P. bracteatum Lindl. compared to mice treated with dox alone.

Electron paramagnetic resonance (EPR) spectroscopy characterization of wheat grains from plants of different water stress tolerance

Grains of five genotypes of wheat (four Polish and one Finnish), differing in their tolerance to drought stress were chosen for this investigation. Electron paramagnetic resonance spectroscopy allowed observation of transition metal ions (Mn, Fe, Cu) and different types of stable radicals, including semiquinone centers, present in seed coats, as well as several types of carbohydrate radicals found mainly in the inner parts of grains. The content of paramagnetic metal centers was higher in sensitive genotypes (Radunia, Raweta) than in tolerant ones (Parabola, Nawra), whereas the Finnish genotype (Manu) exhibited intermediate amounts. Similarly, the concentrations of both types of radicals, carbohydrates and semiquinone were significantly higher in the grains originating from more sensitive wheat genotypes. The nature of carbohydrate radicals and their concentrations were confronted with the kinds and amounts of sugars found by the biochemical analyses and microscopy observations. It is suggested that some long lived radicals (semiquinone and starch radicals) occurring in grains could be indicators of stress resistance of wheat plants.

Electron spin resonance measurement of radical scavenging activity of Aronia melanocarpa fruit juice

BACKGROUND

The fruits of Aronia melanocarpa (Michx.) Elliot contain large amounts of phenolic substances, mainly procyanidins, anthocyanins and other flavonoids, and phenolic acids. The ability of phenolic substances to act as antioxidants has been well established.

OBJECTIVE

In this study, we investigated the radical scavenging activity of A. melanocarpa fruit juice (AMFJ).

MATERIALS AND METHODS

The method used was electron spin resonance (ESR) spectroscopy. The galvinoxyl free radical was used as a scavenging object. AMFJ was added to the galvinoxyl free radical solution. The measure of the radical scavenging activity was the decrease of signal intensity.

RESULTS

AMFJ showed a potent antiradical activity causing a strong and rapid decrease of signal intensity as a function of time and juice concentration. This effect of AMFJ was probably due to the activity of its phenolic constituents.

CONCLUSION

The ESR measurements in this study showed a pronounced radical scavenging effect of AMFJ, an important mechanism of its antioxidant activity.

The effects of short-term selenium stress on Polish and Finnish wheat seedlings-EPR, enzymatic and fluorescence studies

Biochemical analyses of antioxidant content were compared with measurements of fluorescence and electron paramagnetic resonance (EPR) to examine the alteration of radicals in wheat seedlings exposed to 2 days of selenium stress. Two genotypes of Polish and one of Finnish wheat, differing in their tolerance to long-term stress treatment, were cultured under hydroponic conditions to achieve the phase of 3-leave seedlings. Afterwards, selenium (sodium selenate, 100 μM concentration) was added to the media. After Se-treatment, all varieties showed an increase in carbohydrates (soluble and starch), ascorbate and glutathione content in comparison to non-stressed plants. These changes were more visible in Finnish wheat. On the basis of lipid peroxidation measurements, Finnish wheat was recognized as the genotype more sensitive to short-term Se-stress than the Polish varieties. The antioxidant enzyme activities (superoxide dismutase, ascorbate peroxidase and glutathione reductase) increased in Polish genotypes, whereas they decreased in Finnish wheat plants cultured on Se media. The action of reactive oxygen species in short-term action of Se stress was confirmed by the reduction of PSII and PSI system activities (measured by fluorescence parameters and EPR, respectively). EPR studies showed changes in redox status (especially connected with Mn(II)/Mn(III), and semiquinone/quinone ratios) in wheat cell after Se treatment. The involvement of the carbohydrate molecules as electron traps in production of long-lived radicals is postulated.