Regular ArticleLipoprotein Oxidation and Measurement of Thiobarbituric Acid Reacting Substances Formation in a Single Microtiter Plate: Its Use for Evaluation of Antioxidants
Abstract
Transition metals catalyze free radical-mediated oxidation of lipids and lipoproteins. This process is currently studied because of its potential relevance to pathological processes like atherosclerosis. Formation of thiobarbituric acid-reacting substances from polyenoic fatty acids is frequently used to follow oxidation of lipids and plasma lipoproteins. We describe here how Cu(II)- and Fe(III)-catalyzed oxidation of human low density lipoprotein or soy bean phospholipids and the photometric evaluation of the thiobarbituric acid-reacting substances formed can be conducted in the same 96-well microtiter plate. The procedure showed a correlation of 0.98 with conventional two-stage fluorimetric and spectrophotometric methods and also showed better reproducibility. The plate method can handle up to one plate per hour with considerably less labor than the test tube assays. The plate procedure required small volumes of diluted samples of lipoproteins lipids and reagents. The method was suitable for testing the concentration-dependent antioxidant potency of substances like probucol, butylated hydroxytoluene, and α-tocopherol. The method can also be used to follow the kinetics of oxidation of lipoproteins.
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Anaesthetic profile of thymol and menthol in zebrafish larvae model
2024, Aquaculture and FisheriesAquaculture procedures such as capturing, handling, and transporting fish can lead to stress in animals. For this reason, anaesthesia has been recommended to reduce fish stress during these procedures. Synthetic and natural anaesthetics such as tricaine methanesulfonate (MS-222) and eugenol (monoterpene) are commonly used; however, biochemical changes and aversive effects have been reported. Other monoterpene compounds such as thymol and menthol, have shown potential anaesthetic effects in fish species. Thus, further investigation of its anaesthetic properties seems imperative, and the use of the zebrafish in the early stages of its development is an appropriate model due to its advantages. Therefore, the aimed to evaluate the anaesthetic profile of thymol and menthol in zebrafish at 72 hpf (hours post fertilisation). Following the determination of the effective anaesthetic concentration, three concentrations (100, 200 and 300 mg/L for thymol and 200, 400 and 500 mg/L for menthol) were further tested by focusing on mortality rate, heart rate, behaviour features of induction and oxidative effects in comparison to MS-222 and eugenol. Both monoterpenes caused anaesthetic effects in a concentration-dependent manner, with concentrations of 200 mg/L exhibiting a similar profile to MS-222 and eugenol, as evidenced by the increased recovery times.
Furthermore, anaesthesia with thymol and menthol caused post-anaesthesia motor pattern abnormalities, which supported some indicators of stress. Slight modifications in physiological parameters and antioxidant changes were observed, but their association with thymol and menthol anaesthesia is unclear. Although supporting its anaesthetic use, more extensive research will be required to fully understand the impact of these natural anaesthetics on fish behaviour and stress levels, ultimately leading to safer and more successful anaesthetic operations in the future.
Pfaffia glomerata polyploid accession compromises male fertility and fetal development
2023, Journal of EthnopharmacologyPfaffia glomerata (Spreng.) Pedersen has traditionally been used as a tonic and a stimulant by the Brazilian population. It shows higher biomass accumulation and production of secondary compounds, such as the phytosterol 20-hydroxyecdysone.
The present study aimed to evaluate the effects of the hydroalcoholic extract of the root of tetraploid P. glomerata (BGEt) on testicular parenchyma, and its implications on fertility.
Adult Swiss mice were divided as: control (water) and sildenafil citrate (7 mg/kg), BGEt at 100, 200, and 400 mg/kg, and BGEtD 200 mg/kg (treated with BGE every three days). Males (n = 4/group) were mated with normal untreated adult females to assess fertility rates, while other animals (n = 6/group) were euthanized for testis, epididymis, and oxidative stress analyses.
Increase in tubule diameter and epithelium height in the discontinuous group, in addition to an increase in the proportion of tubules with moderate pathologies was observed. The pre-implantation loss was lower in all treated groups. The post-implantation loss was significantly increased in all treated groups, except for the lowest BGEt dose. BGEt intake caused a decrease in daily sperm production, along with the number and quality of sperm in the epididymis. Changes were observed in protein carbonylation and hydrogen peroxide and nitric oxide levels, characterizing oxidative stress.
The hydroalcoholic extract of P. glomerata tetraploid altered sperm and testicular parameters, compromising embryonic development after implantation.
Higher serum uric acid is associated with body fat, retinol-binding protein 4, and antioxidative status in Brazilian children
2023, NutritionThe aim of this study was to evaluate the association of serum uric acid (SUA) with adiposity, adipokines, and anti- and oxidative markers in Brazilian children.
This was a cross-sectional investigation with 378 children ages 8 to 9 y in Viçosa, Minas Gerais, Brazil. Information on sociodemographic and lifestyle characteristics was obtained via questionnaires, and body fat was determined by dual energy x-ray absorptiometry. We compared the distributions of adiposity (total and central), adipokines (adiponectin, chemerin, leptin, and retinol-binding protein 4 [RBP4]), anti- and oxidative markers (plasma ferric reducing antioxidant power [FRAP], superoxide dismutase [SOD], and malondialdehyde [MDA]) by SUA categories using linear regression.
SUA was positively associated with total and central fat. Every standard deviation (SD) of SUA was related, respectively, to a 3.4 (95% confidence interval [CI], 2.4–4.4), 4 (95% CI, 2.8–5.1), 4.2 (95% CI, 2.9–5.5), and 3.5 (95% CI, 2.4–4.6) units higher of total, truncal, android, and gynoid fat. We found a positive association of SUA with RBP4 and FRAP, and a negative association with MDA. Every SD of SUA was related, respectively, to 0.1 (95% CI, 0.01–0.1) and 7.8 (95% CI, 5.5–10.1) units higher of RBP4 and FRAP; and to –0.3 (95% CI, –0.5 to –0.1) units lower of MDA.
SUA was positively associated with adiposity, RBP4, and antioxidative status in Brazilian children.
Study on the antineoplastic and toxicological effects of pomegranate (Punica granatum L.) leaf infusion using the K14-HPV16 transgenic mouse model
2023, Food and Chemical ToxicologyPunica granatum L. (pomegranate) has been used in functional foods due to its various health benefits. However, the in vivo biological potential of its leaf remains little known. This study has aimed to characterize the antineoplastic and toxicological properties of using pomegranate leaf infusion (PLI) on transgenic mice carrying human papillomavirus (HPV) type 16 oncogenes. Thirty-eight mice were divided into 3 wild-type (WT) and 3 transgenic (HPV) groups, with exposure to 0.5% PLI, 1.0% PLI, and water. The animals’ body weight, drink and food consumption were recorded. Internal organs, skin samples and intracardiac blood were collected to evaluate toxicological parameters, neoplastic lesions and oxidative stress. The results indicated that PLI was safe as no mortality, no behavioural disorders and no significant differences in the levels of microhematocrit, serum biochemical markers, internal organ histology, and oxidative stress was found among the WT groups. Histological analysis revealed that HPV animals that consumed PLI exhibited reduced hepatic, renal and cutaneous lesions compared with the HPV control group. Low-dose PLI consumption significantly diminished renal hydronephrosis lesions and relieved dysplasia and carcinoma lesions in the chest skin. Oxidative stress analysis showed that low-dose PLI consumption may have more benefits than high-dose PLI. These results suggest that oral administration of PLI has the potential to alleviate non-neoplastic and neoplastic lesions against HPV16-induced organ and skin injuries, though this requires further scientific research studies.
Nephroprotective effects of Piper nigrum extracts against monosodium glutamate-induced renal toxicity in rats
2023, Scientific AfricanThe toxicological effects of monosodium glutamate (MSG), widely used as a food additive, are a major public health challenge. This research aimed to investigate the nephroprotective effects of methanol and n-hexane extracts of Piper nigrum (MEPN and HEPN, respectively) against MSG-induced renal toxicity in rats.
The phytochemicals, vitamins, and in vitro antioxidant activities were determined using standard protocols. Acute toxicity was determined with thirty-two Swiss albino mice, while thirty male Wistar albino rats were used for the nephroprotective study. The rats were randomly distributed into 6 experimental groups (n = 5). Group 1 (baseline) was not induced or treated; groups 2–6 were given 2 g/kg body weight of MSG. Additionally, group 2 received normal saline; groups 3–6 were given 250 and 500 mg/kg body weight of MEPN and HEPN, respectively. MSG was administered alone for 21 days, after which MSG was concomitantly administered with the extracts for additional 28 days. After treatment, biochemical tests were done on the serum, and a histopathological examination was determined with the kidney.
Both extracts scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reduced ferric ions to ferrous ions in the Ferric Reducing Antioxidant Power (FRAP) assay, with MEPN having higher efficacy. The extracts also ameliorated lipid peroxidation and increased the activities of superoxide dismutase and catalase, as well as the level of reduced glutathione. In addition, intervention with MEPN and HEPN provided nephroprotective effects by decreasing urea and creatinine levels and also improved the histo-architecture of the kidney. This efficacy could be due to the rich phytochemicals and antioxidant vitamins previously identified in the plant.
These findings are critical in focusing attention on abolishing the use of MSG in our food sector and highlights the health benefits of incorporating P. nigrum into our food to avert food and drug toxicity.
Evaluation of the developmental effects of a glyphosate-based herbicide complexed with copper, zinc, and manganese metals in zebrafish.
2022, ChemosphereThe use of glyphosate-based herbicides (GBH) has increased dramatically, being currently the most used herbicides worldwide. Glyphosate acts as a chelating agent, capable of chelate metals. The synergistic effects of metals and agrochemicals may pose an environmental problem as they have been shown to induce neurological abnormalities and behavioural changes in aquatic species. However, as their ecotoxicity effects are poorly understood, evaluating the impacts of GBH complexed with metals is an ecological priority. The main objective of the study was to evaluate the potentially toxic effects caused by exposure to a GBH (1 μg a.i. mL−1), alone or complexed with metals (Copper, Manganese, and Zinc (100 μg L−1)), at environmentally relevant concentrations, during the early period of zebrafish (Danio rerio) embryo development (96 h post-fertilization), a promising model for in vivo developmental studies. To clarify the mechanisms of toxicity involved, lethal and sublethal development endpoints were assessed. At the end of the exposure, biochemical and cell death parameters were evaluated and, 24 h later, different behavioural responses were assessed. The results showed that metals induced higher levels of toxicity. Copper caused high mortality, low hatching, malformations, and changes in biochemical parameters, such as decreased Catalase (CAT) activity, increased Glutathione Peroxidase (GPx), Glutathione S-Transferase (GST), reduced Glutathione (GSH) and decreased Acetylcholinesterase (AChE) activity, also inducing apoptosis and changes in larval behaviour. Manganese increased the activity of SODs enzymes. Zinc increased mortality, reactive oxygen species (ROS) levels, superoxide dismutase activity (SODs) and caused a decrease in AChE activity. Embryos/larvae exposed to the combination of GBH/Metal also showed teratogenic effects during their development but in smaller proportions than the metal alone. Although more studies are needed, the results suggest that GBH may interfere with the mechanisms of metal toxicity at the biochemical, physiological, and behavioural levels of zebrafish.