Effects of Exogenous Antioxidants on Dietary Iron Overload

In dietary iron overload, excess hepatic iron promotes liver damage. The aim was to attenuate free radical-induced liver damage using vitamins. Four groups of 60 Wistar rats were studied: group 1 (control) was fed normal diet, group 2 (Fe) 2.5% pentacarbonyl iron (CI) followed by 0.5% Ferrocene, group 3 (Fe + V gp) CI, Ferrocene, plus vitamins A and E (42× and 10× RDA, respectively), group 4 (Fe – V gp) CI, Ferrocene diet, minus vitamins A and E. At 20 months, glutathione peroxidase (GPx), superoxide dismutase (SOD), Oxygen Radical Absorbance Capacity (ORAC), Ames mutagenicity test, AST, ALT and 4-hydroxynonenal (4-HNE) immunohistochemistry were measured. 8OHdG levels of the Fe + V and Fe – V groups were 346 ± 117 and 455 ± 151, ng/g w.wt, respectively. Fe + V and Fe – V differences were significant (p<0.005). A positive correlation between DNA damage and mutagenesis existed (p<0.005) within the iron-fed gps. AST levels for Fe + V and Fe – V groups were 134.6 ± 48.6 IU and 202.2 ± 50.5 IU, respectively. Similarly, ALT levels were 234.6 ± 48.3 IU and 329.0 ± 48.6 IU, respectively. However, Fe – V and Fe + V groups transaminases were statistically insignificant. 4-HNE was detected in Fe + V and Fe – V gp livers. Vitamins A and E could not prevent hepatic damage

Antioxidant and oxidative stress status in type 2 diabetes and diabetic foot ulcer

ABSTRACT Objectives: Oxidative stress (OS) has been implicated in the aetiology and progression of diabetic complications including diabetic foot ulcer. In the present study, the levels of lipid peroxides (LPO), a marker of lipid peroxidation and 8-hydroxy-2’-deoxyguanosine (8-OHdG), a marker of DNA damage as well as the enzymatic antioxidant activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in type 2 diabetes mellitus and diabetic foot ulcer subjects were assessed and compared with apparently healthy normal subjects in order to understand the involvement of OS in diabetic foot ulcer subject. Design: The above-mentioned OS markers were measured in 50 subjects for each of the following groups: type 2 diabetes mellitus (DM), diabetic foot ulcer (DF) and non diabetic control (NC). Results: Significant elevated values of LPO and 8-OHdG were found in DM subjects: 39.86% and 45.53% increase respectively compared to the NC subjects. This increase in both parameters was greater for DF subjects: 80.23% and 53.91% respectively. SOD activities were significantly reduced in DM (14.82%) and DF (4.09%) subjects in contrast with elevated activities of GPx observed in DM (21.87%) and DF (20.94%) subjects. In this study, positive correlations between glycated hemoglobin/fasting plasma glucose (HbA1c/FPG) and the following OS parameters: LPO, 8-OHdG and GPx were observed. However, correlation between the above glycemic components and SOD was found to be negative. Conclusion: Increased oxidation subsequent to diabetic conditions induces an overexpression of GPx activity suggesting a compensatory mechanism by the body to prevent further tissue damage in these subjects

Indigenous African foods plants: vehicles of disease or sources of protection?

The impact of recurring droughts and endemic poverty-related chronic diseases reduces the ability of poor rural households to cope with the demands of providing health sustaining food for the family. The dietary safety and health-supporting qualities of traditional staples are important factors in consumer health. Because all crops are subject to fungal infestation, mycotoxin contamination of food has become a global problem. Homegrown foods of rural communities are not evaluated for consumer safety, and data pertaining to their health benefits are limited. This study determines the mycological quality of traditional leafy vegetables, commonly referred to as morogo, and investigates the folate content of such crops, as well as the antimutagenic and anticarcinogenic potential of indigenous rooibos tea and other traditional food and medicinal plants. Results showed that a notable number of fungi isolated from morogo belonged to genera with known toxigenic species. Morogo plants were shown to be relatively folate-rich, and varying degrees of antimutagenic and anticarcinogenic activity were demonstrated for extracts from white and black Bambara groundnut, rooibos, cancer bush and devil\'s claw. Possible health-injuring impacts associated with chronic dietary exposure to certain mycotoxins, as well as health-supportive qualities of some functional foods and medicinal plants, are discussed. Keywords: Traditional morogo, edible plants, mycological stability, healthprotecting qualities Indilinga: African Journal of Indigenous Knowledge Systems (IAJIKS) Vol. 4(1) 2005: 270-27

Antioxidant and oxidative stress status in type 2 diabetes and diabetic foot ulcer

Objective. Oxidative stress (OS) has been implicated in the aetiology and progression of diabetic complications including diabetic foot ulcer. In this study, the levels of lipid peroxides (LPO) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as well as the enzymatic antioxidant activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in type 2 diabetes mellitus and diabetic foot ulcer subjects were assessed and compared with apparently healthy normal subjects to understand the involvement of OS in the subjects. Method. The abovementioned OS markers were measured in 50 subjects for each of the following groups: type 2 diabetes mellitus (DM), diabetic foot ulcer (DF) and non-diabetic control (NC). Results. Significant elevated values of LPO (39.86%) and 8-OHdG (45.53%) were found in DM subjects compared with the NC subjects. This increase in both parameters was greater for DF subjects: 80.23% and 53.91% respectively. SOD activities were significantly reduced in DM (14.82%) and DF (4.09%) subjects in contrast with elevated activities of GPx observed in DM (21.87%) and DF (20.94%) subjects. Glycated haemoglobin/fasting plasma glucose (HbA1c/FPG) correlated positively with LPO, 8-OHdG and GPx, whereas a negative correlation was observed for SOD. Conclusion. Increased oxidation subsequent to diabetic conditions induces an over-expression of GPx activity suggesting a compensatory mechanism by the body to prevent further tissue damage in the subjects. JEMDSA Vol. 13 (2) 2008: pp. 58-6

Inhibition of phorbol ester-induced COX-2 expression by some edible African plants

Cancer bush (CB, Sutherlandia frutescens), Devil's claw (DEV, Harpagophytum procumbens), Rooibos tea (RT, Aspalathus linearis), and Bambara groundnut (BB, Vignea subterranean) have been used to treat some malignancies and inflammatory disorders in Africa. However, biochemical basis for chemopreventive effects of these medicinal plants remains unclear. An abnormally elevated expression of cyclooxygenase-2 (COX-2) has been implicated in pathogenesis and progression of carcinogenesis. In the present study, we found that the methanol extracts of CB, DEV, RT, and BB inhibited, to a different extent, 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced COX-2 expression in human breast epithelial (MCF10A) cells and in mouse skin in vivo. To determine the molecular mechanism of COX-2 inhibition by the above medicinal plants, we examined their effects on activation of NF-kappaB which is one of the major transcription factors responsible for regulating COX-2 expression. Methanol extracts of both CB and BB inhibited the DNA binding of NF-kappaB activated by TPA in MCF10A cells in a dose-dependent manner. Based on above findings, CB and BB are likely to inhibit TPA-induced COX-2 expression through suppression of DNA binding of NF-kappaB, which may contribute to the chemopreventive or chemoprotective activity of these African plants

Inhibitory effects of the extracts of Sutherlandia frutescens (L.) R. Br. and Harpagophytum procumbens DC. on phorbol ester-induced COX-2 expression in mouse skin: AP-1 and CREB as potential upstream targets

Numerous anti-nflammatory agents have been shown to exert chemopreventive activity by targeting cyclooxygenase (COX)2, a rate-limiting enzyme involved in the inflammatory process. Sutherlandia frutescens (L.) R. Br. and Harpagophytum procumbens DC., which are commonly known as Cancer bush (CB) and Devil's claw (DC), respectively, have long been used in South Africa for the management of pain and inflammation. In the present study, we investigated the effects of methanolic extracts of CB and DC on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced COX-2 expression in mouse skin. Topical application of both extracts inhibited TPA-induced COX-2 expression. As an underlying mechanism of COX-2 inhibition, these extracts diminished TPA-stimulated catalytic activity of extracellular signal-regulated protein kinase (ERK), which is known to regulate the activation of eukaryotic transcription factors mediating COX-2 induction. While TPA-induced activation of nuclear factor-kappaB remained unaffected by both extracts, they inhibited TPA-induced activation of activator protein-1 (AP-1) and attenuated the expression of its key component c-Fos. In another study, topical application of TPA induced DNA binding of cyclic AMP response element binding (CREB) protein in mouse skin in vivo, which was abrogated by pretreatment with either CB or DC. (C) 2004 Elsevier Ireland Ltd. All rights reserved