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Context: Ultraviolet radiation (UV) was reported to cause oxidative stress. Hibiscus sabdariffa L. (Malvaceae) calyx is commonly used in traditional Asian and African medicines and possesses strong antioxidant capacity due to its anthocyanin (ANTH) content. Objective: This study researched the possible protective role of Hibiscus sabdariffa calyx extract (HSCE) in UVC exposure of rats. Material and methods: Levels of serum enzymes, renal function tests, and some oxidant/antioxidant biomarkers of skin, lens, and retina tissues were monitored. Rats were exposed to UVC 4 h daily for 40 d and simultaneously received HSCE containing 2.5, 5, and 10 mg doses of ANTH in drinking water. Results: Significant ( p < 0.05) increases in the levels of serum aminotransferases, lactate dehydrogenase, urea, creatinine, and uric acid were noted after UVC exposure. In skin, lens, and retina tissues, total oxidant status, oxidative stress index, lipid peroxidation, and protein oxidation escalated markedly ( p < 0.05) whereas total antioxidant status, reduced glutathione, and superoxide dismutase decreased dramatically ( p < 0.05) related to UVC. Co-administration of HSCE with each ANTH dose significantly ( p < 0.05) reversed aforementioned parameters (except total oxidant status) almost in all tissues. The LD50 of HSCE in rats was determined to be above 5000 mg/kg. Discussion and conclusion: Our data revealed that HSCE has a remarkable potential to counteract UVC-caused impairments, probably through its antioxidant and free radical-defusing effects. Therefore, HSCE could be useful against some cutaneous and ocular diseases in which UV and oxidative stress have a role in the etiopathogenesis. [ABSTRACT FROM AUTHOR]

Objectives: There are only a few earlier studies suggesting relationship between isotretinoin treatment and oxidative stress however, their results are conflicting. Therefore we aimed to concretize the influence of isotretinoin treatment on oxidant/antioxidant status together with paraoxonase-1 (PON1) activity for the first time. Methods: The study was performed on serum samples obtained from 35 acne vulgaris patients before and after three months of isotretinoin treatment. PON1 activity, total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI) and some routine biochemical parameters were monitored. Results: Dramatically decreased PON1 activity ( p < 0.001), increased TOS level and OSI value ( p < 0.001 and p < 0.001; respectively) as well as slightly diminished TAC level were noted in posttreatment stage. Moreover significant increases were observed in lactate dehydrogenase and gamma glutamyl transpeptidase activities and levels of total cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol, triglycerides, low density lipoprotein cholesterol/high density lipoprotein cholesterol ratio respectively ( p < 0.05, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001 and p < 0.001) while marked decrease was seen in high density lipoprotein cholesterol ( p < 0.01). Conclusion: This study revealed that decreased PON1 activity and increased oxidative stress may have a crucial role in the pathogenesis of isotretinoin's side effects. Further studies on a large number of patients are needed to verify these results. [ABSTRACT FROM AUTHOR]

Cisplatin (CP) is a widely used cytotoxic agent against cancer, and high doses of CP have been known to cause nephrotoxicity and hepatotoxicity. Some reports claim that antioxidants can reduce CP-induced toxicity. This study investigated the hepatoprotective, nephroprotective, and antioxidant activity of Urtica dioica L methanolic extract (UDME) against CP toxicity in Erhlich ascites tumor (EAT)-bearing mice. Levels of serum hepatic enzymes, renal function markers, and oxidant/antioxidant parameters of liver tissue were measured. Mice were inoculated with EAT on day 0 and treated with nothing else for 24 hours. After a single dose of CP administration on day 1, the extract was given at the doses of 50, 100, 200, and 400 mg/kg body weight daily during 6 days. Almost all doses of UDME performed a significant ( P < 0.05) preventive role against CP toxicity by decreasing aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, blood urea nitrogen, creatinine, lipid peroxidation, protein oxidation levels, and myeloperoxidase activity, as well as increasing reduced glutathione content, superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase activities. This suggests that UDME has a protective capacity and antioxidant activity against CP toxicity in EAT-bearing mice, probably by promoting antioxidative defense systems. [ABSTRACT FROM AUTHOR]

Human studies suggest that free radicals and antioxidant enzymes can alter according to age, lifestyle, environment, and habits. Individuals having a marked circadian preference, that is, morning type or evening type, differ on a number of psychological, behavioral, and biological variables. The aim of this study was to determine whether chronotype impacts some parameters of oxidant and antioxidant status. For this purpose, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and myeloperoxidase (MPO) activities and the levels of reduced glutathione (GSH) and malondialdehyde (MDA) were measured in 96 healthy volunteers (including 32 morning-type, 32 intermediate-type, and 32 evening-type individuals), aged between 21 and 26 years. There were no significant relationships between the chronotypes with regard to oxidant and antioxidant parameters. Our results indicated that the levels of GSH and MDA as well as the activities of GSH-Px, MPO, and SOD were not influenced by the individual circadian differences in our sample. These results were discussed using the theoretical concepts of age-related factors, and suggestions for further research presented. [ABSTRACT FROM AUTHOR]

In the present study, the influence of subchronic effects of two plant growth regulators (PGRs) [Abcisic acid (ABA) and Gibberellic acid (GA3)] on antioxidant defense systems [reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation level (malondialdehyde = MDA) in various tissues of the rat were investigated during treatment as a drinking water model. 75 ppm of ABA and GA3 in drinking water were continuously administered orally to rats (Sprague-Dawley albino) ad libitum for 50 days. The PGRs treatments caused different effects on the antioxidant defense systems and MDA content of dosed rats compared to controls. The lipid peroxidation end product MDA significantly increased in the lungs, heart and kidney of rats treated with GA3 without significant change in the spleen. ABA caused also a significant increase in MDA content in the spleen, lungs, heart and kidney. The GSH levels were significantly depleted in the spleen, lungs and stomach of rats treated with ABA without any change in the tissues of rats treated with GA3 except the kidney where it increased. Antioxidant enzyme activities such as SOD significantly increased in the lungs and stomach and decreased in the spleen and heart tissues of rats treated with GA3. Meanwhile, SOD significantly decreased in the spleen, heart and kidney and increased in the lungs of rats treated with ABA. While CAT activity significantly decreased in the lungs of rats treated with GA3, a significant increase occurred in the heart of rats treated with both PGRs. On the other hand, the ancillary enzyme GR activity in the tissues were either significantly depleted or not changed with PGRs treatment. The drug metabolizing enzyme GST activity significantly decreased in the lungs of rats treated with ABA but increased in the stomach of rats treated with both PGRs. As a conclusion, the rats resisted oxidative stress via the antioxidant mechanism. But the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat's tissues. This data, along with changes, suggests that PGRs produced substantial systemic organ toxicity in the spleen, lungs, stomach, heart and kidney during a 50-day period of subchronic exposure. [ABSTRACT FROM AUTHOR]