Interference of Metals and Medications with the Detection of Lipid Peroxidation in Humans by Photometric TBARS Assay

WOS: 000324492600014The thiobarbituric acid (TBA) reaction with malondialdehyde (MDA) is commonly used to measure free radical- mediated oxidative changes in lipids containing polyunsaturated fatty acids (PUFA). This test has had a broad range of applications since it was introduced in 1949; among others, researchers have used this test to evaluate toxic outcomes of chemical exposure in many environmental and occupational settings. However, the test has been criticized because of its low specificity. It has been reported that several endogenous or exogenous compounds, including drugs and metals, may interfere with a photometric or fluorimetric assay. The wide use of this test in occupational toxicology to measure lipid peroxidation (LPO) in humans led us to investigate whether simultaneous medications with drugs or exposure to metals interfere with the assay. We show here that, in the presence of bismuth or medazepam, the test gives erroneous results in a spectrophotometric assay. Among the tested 45 compounds, bismuth inhibits the formation of the MDA-TBA complex. In contrast, medazepam caused 2-fold higher absorbance compared to the absorbance obtained in the absence of the drug. UV spectrum analysis revealed that another unknown product is formed with an absorption maximum of 458 nm. In addition, medazepam yielded a second product with TBA whose absorption spectrum was essentially identical to that of the MDA standard. We have succeeded in separating this product and quantifying the MDA-TBA complex accurately by a HPLC method. Though it requires more sophisticated equipment, we suggest using HPLC for MDA quantification in biological samples, which might contain potentially interfering compounds

Evaluation of Oxidative and Antioxidative Parameters in Pediatric Hematopoietic SCT Patients

Conditioning regimens preceding hematopoietic SCT (HSCT) usually consist of high-dose chemotherapy. Chemotherapy and radiation therapy are associated with increased formation of free radicals and depletion of critical plasma and tissue antioxidants. Oxidative stress and antioxidant depletion have been described during the transplantation period in HSCT patients. In a limited number of studies, it was observed that the conditioning regimen resulted in oxidative stress and antioxidant depletion in HSCT patients. The objective of this study was to look for further evidence of oxidative stress and antioxidant status in pediatric HSCT patients. In this study, blood samples were collected from 21 pediatric allo-HSCT patients before and after conditioning therapy. Erythrocyte and plasma malondialdehyde (MDA) levels, erythrocyte reduced and oxidized glutathione (GSH) levels, erythrocyte antioxidant enzymes activities, plasma α-tocopherol and β-carotene levels were determined. After high-dose chemotherapy, erythrocyte and plasma MDA levels increased. Reduced GSH levels decreased whereas oxidized GSH levels increased first and then decreased significantly compared with the values before the chemotherapy regimen. It was also observed that catalase, superoxide dismutase and GSH-S-transferase activities decreased, but there was no change in GSH peroxidase activity. On the other hand, plasma α-tocopherol levels increased, but β-carotene levels did not change.Wo

Evaluation of skin irritation potentials of different cosmetic products in Turkish market by reconstructed human epidermis model.

Human skin is a protective barrier against the toxic effects of cosmetics. Marketing of cosmetic products with ingredients tested on animals was prohibited in 2013. Since then, safety evaluation of cosmetic products is performed by using alternative in vitro toxicity tests. In vitro 3-D reconstructed human epidermis (RhE) tissue models are now used to define skin irritation/corrosion potentials of cosmetic ingredients and end-products. The main aim of this study was to evaluate skin irritation potentials of topically used cosmetic end-products which were marketed in Turkey during 2015-2017, by using the EpiDerm in vitro 3D-human skin model. Sixty widely used cosmetic products were collected from different markets/cosmetic shops. Among hair care products, only one shampoo was found to be strong/severe skin irritant/possible corrosive while 22 shampoos were moderate skin irritant and 11 shampoos were moderate to mild skin irritant. Among 6 skin care products, one was found to be moderate to mild skin irritant. We can suggest that alternative in vitro tests should continuously be used to test both the ingredients and the final cosmetic formulations

Cofactor metals and antioxidant enzymes in cisplatin-treated rats: effect of antioxidant intervention

WOS: 000369918800002PubMed ID: 25346999We explored the association between the activities of antioxidant enzymes and their metallic cofactors in rats treated with cisplatin. The antioxidant effects of aminoguanidine, and a combination of vitamins E and C were investigated. Plasma platin was significantly lower than liver and kidney. Cisplatin treatment caused significant increase in plasma Se-glutathione peroxidase activity. Activities of Se-glutathione peroxidase, glutathione S-transferase, catalase and Cu, Zn-superoxide dismutase have been found to be significantly decreased in liver and kidney compared to controls. Zn levels in these organs were diminished upon cisplatin treatment, while levels of Cu were unaffected. Interestingly, levels of iron, the cofactor of catalase, were found to be significantly increased in liver and kidney. Intervention with aminoguanidine or vitamins was generally prevented cisplatin-caused changes in the activity of enzymes and in the tissue levels of cofactor metals. These observations suggest that relation between activities of enzymes and levels of cofactor metals is multifactorial.Hacettepe University Research Center OfficeHacettepe University [04 DD 02 301 002]The authors declare that there is no conflict of interest. This study was supported by Hacettepe University Research Center Office, Grant no. 04 DD 02 301 002

Serum Aflatoxin Levels Of The Healthy Adult Population Living In The North And South Regions Of Turkey

Objective: To determine the serum concentrations of aflatoxin B-1 (AFB(1)), aflatoxin B-2 (AFB(2)), aflatoxin G(1) (AFG(1)) and aflatoxin G(2) (AFG(2)) in the healthy adult population living in both the Black Sea and Mediterranean regions of Turkey and to investigate the regional, seasonal and gender variability in aflatoxins (AF) exposure in these regions. Design: Serum AFB(1), AFB(2), AFG(1) and AFG(2) concentrations were analysed by HPLC. Settings: In total, four hundred and eighty-four serum samples were analysed. Subjects: Four hundred and eighty-four healthy adult volunteers living in rural areas of the Black Sea and Mediterranean regions of Turkey were studied. Results: The mean serum concentration of total AF in the Black Sea region was 1.33 ppb (min-max 0.15-3.38 ppb) and 0.90 ppb (min-max 0.18-2.48 ppb) for summer and winter, respectively. In the Mediterranean region, the mean serum concentration of total AF was determined as 0.55 ppb (range 0.04-1.72 ppb) for summer and 0? 45 ppb (range 0.12-1.43 ppb) for winter. The total AF concentrations in serum samples were statistically higher in summer compared with winter for the two regions. The differences between the regions were statistically significant concerning all samples, with higher total AF concentrations in the Black Sea region. Conclusions: The overall results suggest that the Turkish population living in these two regions is continuously exposed to AF, particularly in the summer, and that mycotoxin contamination in food should be monitored routinely for food safety and human health

Polyphenolic Constituents And Antioxidant Potential Of Geranium Stepporum Davis

The crude MeOH extract prepared from the aerial parts of G. stepporum and its EtOAc, n-BuOH, H(2)O subextracts were screened for their inhibitory activity on H(2)O(2)-induced lipid peroxidation in human red blood cells. The EtOAc subextract was found to be the most active one and its chemical composition was further analysed. Six polyphenolic secondary metabolites including quercetin (1), rutin (2), methyl gallate (3), pusilagin (4), 1,3,6-tri-O-galloyl-beta-glucospyranose (5) and 1,2,3,4,6-penta-O-galloyl-beta-glucopyranose (6) were isolated from the EtOAc extract by successive chromatographic methods (Sephadex CC, silica gel CC and P-TLC). The structures of the isolates were elucidated by 1D- and 2D-NMR and MS. This is the first report of occurrence of hydrolysable tannins in G. stepporum.Wo

Antioxidant galloylated flavonoids from Geranium tuberosum L. subsp tuberosum

Phytochemical investigations on the most active EtOAc extract led to the isolation of 9 flavonoids [quercetin (1), quercetin 3-O-beta-glucopyranoside (2), quercetin 3-O-beta-galactopyranoside (3), quercetin 3-O-(2 ''-O-galloyl)-beta-glucopyranoside (4), quercetin 3-O-(2 ''-O-galloyl)-beta-galactopyranoside (5), quercetin 3-O-(6 ''-O-galloyl)-beta-glucopyranoside (6), quercetin 3-O-(6 ''-O-galloyl)-beta-galactopyranoside (7), quercetin-3-O-alpha-arabinofuranoside (8), and quercetin-3-O-alpha-rhamnopyranosyl-(1 -> 6)-beta-glucopyranoside (9)] and a simple phenolic compound (methyl gallate) (10). The structures of the compounds were elucidated by 1- and 2-dimensional NMR techniques (H-1, C-13, COSY, HMBC, and HMQC) and ESI-TOF-MS spectrometry. H2O2-induced lipid peroxidation inhibitor effects in human red blood cells of different extracts of G. tuberosum L. subsp. tuberosum aerial parts were also investigated. All the compounds tested showed antioxidant activity

Evaluation of skin irritation potentials of different cosmetic products in Turkish market by reconstructed human epidermis model

Human skin is a protective barrier against the toxic effects of cosmetics. Marketing of cosmetic products with ingredients tested on animals was prohibited in 2013. Since then, safety evaluation of cosmetic products is performed by using alternative in vitro toxicity tests. In vitro 3-D reconstructed human epidermis (RhE) tissue models are now used to define skin irritation/corrosion potentials of cosmetic ingredients and end-products. The main aim of this study was to evaluate skin irritation potentials of topically used cosmetic end-products which were marketed in Turkey during 2015-2017, by using the EpiDerm in vitro 3D-human skin model. Sixty widely used cosmetic products were collected from different markets/cosmetic shops. Among hair care products, only one shampoo was found to be strong/severe skin irritant/possible corrosive while 22 shampoos were moderate skin irritant and 11 shampoos were moderate to mild skin irritant. Among 6 skin care products, one was found to be moderate to mild skin irritant. We can suggest that alternative in vitro tests should continuously be used to test both the ingredients and the final cosmetic formulations

Antioxidant Effects of Secondary Metabolites from Geranium psilostemon

An investigation was made of the effects on endogenous antioxidant enzyme activities and H2O2-induced lipid peroxidation inhibition in human red blood cells of the crude MeOH extract and its EtOAc, n-BuOH, and H2O sub-extracts obtained from aerial parts of Geranium psilostemon Ledeb., as well as compounds isolated from the most active EtOAc extract. Gallic acid (1), methyl gallate (2), pusilagin (3), 1,3,6-tri-O-galloyl-beta-glucopyranoside (4), 1,2,3,4,6-penta-O-galloyl-beta-glucopyranoside (5), kaempferol (6), quercetin (7), kaempferol 7-O-alpha-rhamnopyranoside (8), and quercetin 7-O-alpha-rhamnopyranoside (9) were isolated from the aerial parts of the title plant, and their structures identified from spectroscopic (UV, 1D- and 2D- NMR) and spectrometric (TOF-MS) data. All extracts and isolated compounds inhibited H2O2-induced lipid peroxidation and also enhanced the activity of superoxide dismutase (SOD) and catalase (CAT)

Flavonoid Derivatives From The Aerial Parts Of Trifolium Trichocephalum M. Bieb. And Their Antioxidant And Cytotoxic Activity

Trifolium L. species with a rich isoflavone content have been used as expectorant, analgesic, antiseptic, tonic, and wound- healer in folk medicine. The aim of the study is to evaluate pharmacological properties of the extracts and isolated compounds of T. tricocephalum. Phytochemical investigation of the aerial parts of T. trichocephalum led to the isolation of daidzein, genistein, quercetin, and daidzein 4'-O-beta-glucoside for the first time from this species. Isolated compounds along with the methanol extract, water, ethyl acetate and chloroform subextracts were tested for their radical scavenging and cytotoxic activity which was evaluated by MTT assay. According to the results of activity tests, extracts showed a concentration-dependent radical scavenging activity as well as cytotoxic effect on HepG2 cells at 400 mu g/mL, whereas the compounds did not exert any obvious cytotoxic effect at tested concentrations.Wo