Oxidative Damage In Human Cells Research Articles

Quercetin and kaempferol from saffron petals alleviated hydrogen peroxide-induced oxidative damage in B16 cells.

Saffron petals are usually considered as waste after saffron harvest. However, saffron petals contain many important phytochemical components (e.g. quercetin and kaempferol), which may alleviate oxidative damage in human cells. The contents of flavonoids and crocin in different parts of saffron were analyzed. The protective effects of flavonoids from saffron on oxidative damage of B16 cells were investigated. Saffron stigma contained high contents of crocin and picrocrocin, whereas flavonoid content (quercetin, 4.03 ± 0.33 mg g-1 DW; kaempferol, 47.80 ± 0.60 mg g-1 DW) was higher in saffron petals than in other parts. Incubation of B16 cells with quercetin (10-30 μmol L-1) and kaempferol (20-30 μmol L-1) obtained from saffron extracts could significantly increase the total antioxidant capacity (T-AOC) and the activity of NADPH:dehydrogenase quinone-1 (NQO1) to alleviate H2O2-induced oxidative damage. Quercetin was better than kaempferol in increasing NQO1 activity and T-AOC. Quercetin extracted from saffron petals could induce NQO1 expression through regulating kelch-like ECH-associated protein-1/nuclear factor erythroid 2-related factor-2 signaling pathway to protect B16 cells from oxidative damage. The content of kaempferol-3-O-sophoroside and quercetin-3-O-sophoroside was higher in saffron petals than in other parts of saffron. The kaempferol and quercetin obtained from saffron petals could enhance the activity of antioxidant enzyme NQO1 and T-AOC in B16 cells. This indicated that saffron petals, as a potential functional food, may prevent diseases caused by oxidative stress. © 2024 Society of Chemical Industry.

Phaeodactylum tricornutum as a stable platform for pilot scale production and investigation of the viability of spirulina fucoxanthin as a commercial lipolysis active novel compound

The nutraceutical market has experienced a significant growth over the last years, due to changing consumer preferences towards products of natural and organic origin. One of the main areas of interest in this field is microalgae-derived carotenoids, whose antioxidant activity protects against oxidative damage in human cells. The diatom Phaeodactylum tricornutum has been widely studied due to its high fucoxanthin content (antioxidant carotenoid). However, pilot and industrial scale experiments to realize continuous and stable production of P. tricornutum and extracted fucoxanthin are limited. For this reason, this research focuses on the study of the fucoxanthin production, going through culture, harvesting, scaling procedure and encapsulation stage. Finally, the optimal culture conditions for a fucoxanthin production of 2.5 mg/day/L were verified. Furthermore, the antioxidant capacity showed a decrease during storage, but still presented a capacity of 18 months, with improved performance when encapsulated with spirulina. The study carried out on encapsulated fucoxanthin-spirulina shows an inhibitory effect on lipogenesis at all concentrations tested in the 3T3-L1 cell line and a lipolytic efficacy at concentrations of 0.2 mg/mL and 0.1 mg/mL in the 3T3-L1 cell line.

Optimization of ultrasonic-assisted polysaccharide extraction from Hyperici Perforati Herba using response surface methodology and assessment of its antioxidant activity

This study performed a comprehensive investigation of Hyperici Perforati Herba polysaccharide (HPHP) regarding the development and optimization of extraction methods, elucidation of structure and characteristics, and determination of antioxidant activities. An ultrasonic-assisted extraction method, which offered advantages in terms of the extraction yield and energy efficiency, was developed by response surface analysis. The following optimum conditions were determined: a crushing degree at 65 mesh, ultrasonic time at 50 min and temperature of 43 °C. Through enzyme-mediated deproteination via the Sevag method, activated carbon depigmentation, and DEAE-52 and Sephadex G-100 column elution, three HPHPs were obtained, and their monosaccharides mainly included mannose, galactose, glucose and arabinose. The molar weights were 8.347, 1.199 and 22.426 kDa, respectively. The HPHP structures were an amorphous aggregate of spherical-like shapes with a rough surface of pores and crevices, which presented characteristic Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectra of polysaccharides. Their main glucosidic linkage is the α-type configuration. Moreover, HPHPs exhibited strong scavenging activity for DPPH·, ABTS·+, OH· and O2·− radicals; good ferric reducing power; and effective protection against oxidative damage in human cells. Overall, the results of this work underpinned a fundamental understanding of HPHPs, thus providing a potential antioxidant for further research and development.

Continuous blue lighting and elevated carbon dioxide concentration rapidly increase chlorogenic acid content in young lettuce plants

Chlorogenic acid (CGA) is a strong antioxidant that potentially reduces oxidative damage in human cells. In this study, the effects of environmental factors such as photoperiod, light quality and intensity, and CO2 concentration on the growth and CGA content of lettuce (Lactuca sativa L.) were evaluated. CGA content in fresh lettuce increased under high light intensity treatments, doubling in concentration under 200 μmol m−2 s-1 compared to 100 μmol m−2 s-1. Elevated CO2 concentration also increased CGA content in fresh lettuce, quadrupling in concentration when grown at 1000 ppm compared to 400 ppm. Furthermore, there was a compound effect of light intensity and CO2 concentration whereby a light intensity level of 200 μmol m−2 s-1 and CO2 of 1000 ppm produced an even higher concentration of CGA, 199 mg per 100 g of fresh lettuce. Increased CGA concentration because of continuous lighting and elevated CO2 was observed under both fluorescent light and blue LED, but not under red LED treatment. Increased day length also induced higher CGA content in lettuce plants. These results show that continuous lighting, including blue spectrum and elevated CO2 concentration can cause higher CGA accumulation in lettuce plants. The observed increase in CGA content was induced only for 2 days after treatment was initiated. One possible interpretation of the data is that physiological stress caused by excess photosynthesis under continuous lighting results in higher CGA content to protect the plant body from high levels of reactive oxidative species. In addition, blue light and CO2 could be stimulus signals for inducing high CGA accumulation via metabolite changes.

Antioxidant activity and protective effects against oxidative damage of human cells induced by X-radiation of phenolic glycosides isolated from pepper fruits Capsicum annuum L.

The antioxidant and radioprotective effects of the phenolic glycosides from Capsicum annuum L. were examined. There were: sinapoyl-E-glucoside, quercetin-3-O-rhamnoside-7-O-glucoside, quercetin-3-O-rhamnoside and luteolin-7-O-(2-apiosyl)-glucoside. To the best of our knowledge, this is the first study to assay these compounds for their radioprotective effect on human cell lymphocytes in response to oxidative damage induced by X radiation and their antioxidant abilities. Investigated compounds showed weaker antiradical activities, but their radioprotective potentials were higher than those of their aglycones. Quercetin-3-O-rhamnoside showed the highest radioprotective activity (50% according to control). Furthermore, quercetin and luteolin derivatives, in contrast to free aglycones, were not cytotoxic against human lymphocytes for all concentrations tested. The best correlation between radioprotective and antiradical activities of the investigated compounds was observed in the relationship to O2− generated using the NADH/PMS method (R2=0.859). Thus, we propose that superoxide radical scavenging activity is a useful method for screening for compounds with promising radioprotective potential.

Antioxidant effects of quercetin and naringenin are associated with impaired neutrophil microbicidal activity.

Naringenin and quercetin are considered antioxidant compounds with promising activity against oxidative damage in human cells. However, no reports have described their effects on reactive oxygen species (ROS) production by phagocytes during microbicidal activity. Thus, the present study evaluated the effects of naringenin and quercetin on ROS production, specifically hypochlorous acid (HOCl), and their involvement in the microbicidal activity of neutrophils. Naringenin and quercetin inhibited HOCl production through different systems, but this inhibition was more pronounced for quercetin, even in the cell-free systems. With regard to the microbicidal activity of neutrophils, both naringenin and quercetin completely inhibited the killing of Staphylococcus aureus. Altogether, these data indicate that the decrease in the oxidant activity of neutrophils induced by these compounds directly impaired the microbicidal activity of neutrophils. Naringenin and quercetin exerted their effects by controlling the effector mechanisms of ROS production, with both positive and negative effects of these antioxidant agents in oxidative stress conditions and on ROS in the microbicidal activity of phagocytes. The present results challenge the traditional view of antioxidants as improvers of pathological conditions.

Impaired Repair of Ionizing Radiation-Induced DNA Damage in Cockayne Syndrome Cells

Cockayne syndrome (CS) cells are defective in transcription-coupled repair (TCR) and sensitive to oxidizing agents, including ionizing radiation. We examined the hypothesis that TCR plays a role in ionizing radiation-induced oxidative DNA damage repair or alternatively that CS plays a role in transcription elongation after irradiation. Irradiation with doses up to 100 Gy did not inhibit RNA polymerase II-dependent transcription in normal and CS-B fibroblasts. In contrast, RNA polymerase I-dependent transcription was severely inhibited at 5 Gy in normal cells, indicating different mechanisms of transcription response to X rays. The frequency of radiation-induced base damage was 2 × 10(-7) lesions/base/Gy, implying that 150 Gy is required to induce one lesion/30-kb transcription unit; no TCR of X-ray-induced base damage in the p53 gene was observed. Therefore, it is highly unlikely that defective TCR underlies the sensitivity of CS to ionizing radiation. Overall genome repair levels of radiation-induced DNA damage measured by repair replication were significantly reduced in CS-A and CS-B cells. Taken together, the results do not provide evidence for a key role of TCR in repair of radiation-induced oxidative damages in human cells; rather, impaired repair of oxidative lesions throughout the genome may contribute to the CS phenotype.

Tu-P7:172 Potential mechanism for mast cell progenitor transendothelial migration

The black chokeberry, Aronia melanocarpa (Family Rosaceae), is native to North America and was introduced into Europe in the XIX century.Aronia melanocarpa contain particularly high amounts of procyanidins, anthocyanins, and phenolic acids. These antioxidants reduce the oxidative damage of human cells that can lead to cancer, heart disease, diabetes, hypertension, hypercholesterolemia.The black chokeberry may be used in the treatment and prevention of numerous civilization diseases.

Enhanced oxidative damage in human cells harboring A3243G mutation of mitochondrial DNA: implication of oxidative stress in the pathogenesis of mitochondrial diabetes

Mitochondrial oxidative phosphorylation and the ATP production in pancreatic β cells play significant roles in insulin secretion in response to glucose and other nutrients. An A to G mutation in the tRNA Leu(UUR) gene at nucleotide position (np) 3243 of mitochondrial DNA (mtDNA) has been observed in patients with MELAS syndrome and mitochondrial diabetes. Recently, some patients with mitochondrial diabetes associated with the A3243G mtDNA mutation were found to respond to coenzyme Q 10 therapy. Thus, we investigated oxidative stress and peroxidative damage in a series of cybrids carrying either the wild-type adenine or the mutant-type guanine at np 3243 but having otherwise identical mtDNA sequence. The cybrids harboring >90% of the A3243G mutant mtDNA were found to have significantly lower oxygen consumption rate and electron transfer activities, and thereby had lower ATP/ADP ratios and declined energy charge. Importantly, the defective respiratory function elicited by the A3243G mtDNA mutation caused an increased oxidative stress as indicated by the decreased GSH/GSSG ratio and enhanced oxidative damage to lipids. Moreover, the cybrids harboring high proportions of the A3243G mtDNA mutation were found to be much more vulnerable to an exogenous oxidant, tert-butylhydroperoxide. We thus suggest that enhanced oxidative damage and elevated oxidative stress contribute to the decline of mitochondrial function and may be involved in the initiation and progression of the MELAS syndrome and mitochondrial diabetes.