Detoxifying enzymes are present in most epithelial cells of the human gastrointestinal tract where they protect against xenobiotics which may cause cancer. Induction of examples such as glutathione S-transferase (GST) and its thiol conjugate, glutathione (GSH) as well as NAD(P)H: quinoneoxidoreductase (NQO1) facilitate the excretion of carcinogens and thus preventing colon carcinogenesis. Pterostilbene, an analogue of resveratrol, has demonstrated numerous pharmacological activities linked with chemoprevention. This study was conducted to investigate the potential of pterostilbene as a chemopreventive agent using the HT-29 colon cancer cell line to study the modulation of GST and NQO1 activities as well as the GSH level. Initially, our group, established the optimum dose of 24 hours pterostilbene treatment using MTT assays. Then, effects of pterostilbene (0-50 μM) on GST and NQO1 activity and GSH levels were determined using GST, NQO1 and Ellman assays, respectively. MTT assay of pterostilbene (0-100 μM) showed no cytotoxicity toward the HT-29 cell line. Treatment increased GST activity in the cell line significantly (p<0.05) at 12.5 and 25.0 μM. In addition, treatment at 50 μM increased the GSH level significantly (p<0.05). Pterostilbene also enhanced NQO1 activity significantly (p<0.05) at 12.5 μM and 50 μM. Hence, pterostilbene is a potential chemopreventive agent capable of modulation of detoxifiying enzyme levels in HT-29 cells.
The protective effect of methanol extracts of Cassia fistula (flowers, leaves and bark) was examined in vitro in human umbilical vein endothelial cells (HUVEC) against toxicity induced by glycated protein (GFBS) in vitro. The experiments consisted of eight groups of HUVEC with five flasks in each group. Group I was treated with 15% FBS, group II with GFBS (70 microM) alone, and the other six groups were treated with GFBS plus 25 and 50 microg of each of the three types of C. fistula extracts. After 72 h of incubation, cells were collected and tested for lipid peroxidation, antioxidant enzyme activities and glutathione S-transferase (GST). The protective effect of C. fistula extracts against GFBS-induced cytotoxicity was examined in HUVEC by using trypan blue exclusion and MTT assays. Results showed that HUVEC incubated with GFBS alone showed a significant (P < 0.001) elevation of lipid peroxidation accompanied by depletion of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione reductase (GR), in addition to decreased cytosolic GST. Treatment of HUVEC with C. fistula extracts at a concentration of 25 and 50 microg significantly decreased lipid peroxidation and normalized the activities of the antioxidant enzymes and GST levels in a concentration-dependent manner. Morphological changes of HUVEC were compared with respective controls; in addition, the C. fistula extracts increased the viability of HUVEC damaged by GFBS. A protective effect of C. fistula extracts on HUVEC against GFBS-induced toxicity suggested a potential beneficial effect of the extract in preventing diabetic angiopathies.
Several environmental toxins with toxic effects to the bone marrow have been identified. Pathology associated with lead intoxication is due to the cellular damage mediated by free radicals. In the current study, we examined the effect of Etlingera elatior extract on lead-induced changes in the oxidative biomarkers and histology of bone marrow of rats. Sprague-Dawley rats were exposed to 500 ppm lead acetate in their drinking water for 14 days. E. elatior extract was treated orally (100mg/kg body weight) in combination with, or after lead acetate treatment. The results showed that there was a significant increase in lipid hydroperoxide, protein carbonyl content and a significant decrease in total antioxidants, super oxide dismutase, glutathione peroxidase and glutathione--S-transferase in bone marrow after lead acetate exposure. Treatment with E. elatior decreased lipid hydroperoxides and protein carbonyl contents and significantly increased total antioxidants and antioxidant enzymes. Treatments with E. elatior extract also reduced, lead-induced histopathological damage in bone marrow. In conclusion, these data suggest that E. elatior has a powerful antioxidant effect, and it protects the lead acetate-induced bone marrow oxidative damage in rats.
Glucoraphanin is the main glucosinolate found in broccoli and other cruciferous vegetables (Brassicaceae). The objective of the study was to evaluate whether glucoraphanin and its breakdown product sulforaphane, are potent modulators of various phase I and phase II enzymes involved in carcinogen-metabolising enzyme systems in vitro. The glucosinolate glucoraphanin was isolated from cruciferous vegetables and exposed to human hepatoma cell line HepG2 at various concentrations (0-25 μM) for 24 hours. Glucoraphanin at higher concentration (25 μM) decreased dealkylation of methoxyresorufin, a marker for cytochrome P4501 activity; supplementation of the incubation medium with myrosinase (0.018 U), the enzyme that converts glucosinolate to its corresponding isothiocyanate, showed minimal induction in this enzyme activity at concentration 10 μM. Quinone reductase and glutathione S-transferase activities were unaffected by this glucosinolate; however, supplementation of the incubation medium with myrosinase elevated quinone reductase activity. It may be inferred that the breakdown product of glucoraphanin, in this case sulforaphane, is superior than its precursor in modulating carcinogen- metabolising enzyme systems in vitro and this is likely to impact on the chemopreventive activity linked to cruciferous vegetable consumption.
Chlamydia trachomatis is the leading causative agent of bacterial sexually transmitted infections worldwide which can lead to female pelvic inflammatory disease and infertility. A greater understanding of host response during chlamydial infection is essential to design intervention technique to reduce the increasing incidence rate of genital chlamydial infection. In this study, we investigated proteome changes in epithelial cells during C. trachomatis infection by using an isobaric tags for relative and absolute quantitation (iTRAQ) labeling technique coupled with a liquid chromatography-tandem mass spectrometry (LC-MS(3) ) analysis. C. trachomatis (serovar D, MOI 1)-infected HeLa-229 human cervical carcinoma epithelial cells (at 2, 4 and 8 h) showed profound modifications of proteome profile which involved 606 host proteins. MGST1, SUGP2 and ATXN10 were among the top in the list of the differentially upregulated protein. Through pathway analysis, we suggested the involvement of eukaryotic initiation factor 2 (eIF2) and mammalian target of rapamycin (mTOR) in host cells upon C. trachomatis infection. Network analysis underscored the participation of DNA repair mechanism during C. trachomatis infection. In summary, intense modifications of proteome profile in C. trachomatis-infected HeLa-229 cells indicate complex host-pathogen interactions at early phase of chlamydial infection.
This study was conducted to investigate the growth performance, biomarkers of oxidative stress, catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST) as well as the haematological response of African catfish after being fed with fish feed containing different levels of cricket meal. The juvenile fish were assigned to three different treatments with isonitrogenous (35 %) and isoenergetic (19 kJ g(-1)) diets containing 100 % cricket meal (100 % CM), 75 % cricket meal (75 % CM), and 100 % fishmeal (100 % FM) as control groups for 7 weeks. The results indicated that a diet containing 100 % CM and 75 % CM improved growth performance in terms of body weight gain and specific growth rate, when compared to 100 % FM. The feed conversion ratio (FCR) and protein efficiency ratio (PER) did not differ significantly between all diets, but reduced FCR and increased PER were observed with a higher inclusion of cricket meal. A haematological examination of fish demonstrated no significant difference of red blood cells in all diets and white blood cells showed a significantly higher value in fishmeal-fed fish. On the other hand, haemoglobin and haematocrit significantly increased with increasing amounts of cricket meal in the diet. Antioxidant activity of CAT was higher in the 100 % CM group compared to fish fed other diets, whereas GST and SOD showed increasing trends with a higher incorporation of cricket, although insignificant differences were observed between all diets. These results suggest that cricket meal could be an alternative to fishmeal as a protein source in the African catfish diet.
This study investigated the dose-dependent and time-course effects of intramuscular (i.m.) and intraperitoneal (i.p.) injection of benzo[a]pyrene (BaP) on the biomarkers EROD activity, GST activity, concentrations of BaP metabolites in bile, and visceral fat deposits (Lipid Somatic Index, LSI) in African catfish (Clarias gariepinus). Intraperitoneal injection resulted in 4.5 times higher accumulation of total selected biliary FACs than i.m. injection. Hepatic GST activities were inhibited by BaP via both injection methods. Dose-response relationships between BaP injection and both biliary FAC concentrations and hepatic GST activities were linear in the i.p. injected group but nonlinear in the i.m. injected fish. Hepatic EROD activity and LSI were not significantly affected by BaP exposure by either injection route. We conclude that i.p. is a more effective route of exposure than i.m. for future ecotoxicological studies of PAH exposure in C. gariepinus.
Octylphenol (OP) is one of ubiquitous pollutants in the environment. It belongs to endocrine-disrupting chemicals (EDC). It is used in many industrial and agricultural products. Pectin is a family of complex polysaccharides that function as a hydrating agent and cementing material for the cellulose network. The aim of this study was to evaluate the therapeutic effect of pectin in kidney dysfunction, oxidative stress and apoptosis induced by OP exposure. Thirty-two male albino rats were divided into four equal groups; group 1 control was injected intraperitoneally (i.p) with saline [1 ml/kg body weight (bwt)], groups 2, 3 & 4 were injected i.p with OP (50 mg/kg bwt) three days/week over two weeks period where groups 3 & 4 were injected i.p with pectin (25 or 50 mg/kg bwt) three days/week over three weeks period. The results of the present study revealed that OP significantly decreased glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT), reduced glutathione (GSH), glutathione reductase (GR) and superoxide dismutase (SOD) levels while increased significantly lipid peroxidation (MDA), nitric oxide (NO) and protein carbonyls (PC) levels in the kidney tissues. On the other hand, OP increased serum urea and creatinine. Furthermore, OP increased significantly serum uric acid but decreased significantly the kidney weight. Moreover, OP decreased p53 expression while increased bcl-2 expression in the kidney tissue. The treatment with either dose of pectin to OP-exposed rats restores all the above parameters to approach the normal values where pectin at higher dose was more effective than lower one. These results were supported by histopathological investigations. In conclusion, pectin has antioxidant and anti-apoptotic activities in kidney toxicity induced by OP and the effect was dose-dependent.
This study examined the potential of Pseudomonas aeruginosa abundance in the intestines of fish as an indicator of exposure to benzo[a]pyrene (BaP). P. aeruginosa populations were enumerated in juvenile African catfish (Clarias gariepinus) injected intramuscularly three days previous with 0, 10, 30, 40, 50 or 70mg/kg of BaP. Hepatic EROD and GST activities and biliary fluorescent aromatic compounds (FACs) 1-OH BaP, 3-OH BaP, 7,8-D BaP and BaP were quantified to investigate agreements between the new indicator and established fish biomarkers. The shape of bacterial population (logarithm of colony-forming unit) dose-response curve generally matched those of biliary FACs concentrations. Conversely, the EROD and GST dose-response curves were generally the mirror images of the bacterial population curve. Changes in intestinal P. aeruginosa population appear to be an indirect effect of BaP exposure because exposure to 0-100μg/ml BaP had no effect on P. aeruginosa populations grown on agar plates containing BaP. Using intestinal P. aeruginosa population of fish as a universal indicator of BaP pollution in aquatic environments is discussed.Conversely, the EROD and GST dose-response curves were generally the mirror images of the bacterial population curve.
The effects of vitamin C and aloe vera gel extract supplementation on induced hepatocarcinogenesis in male Sprague-Dawley rats (120-150 g) by diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) was investigated. The severity of the carcinogenesis process was determined by measuring gamma-glutamyl transpeptidase (GGT) and the placental form of glutathione S-transferase (GSTP) histochemically in situ and in plasma and liver fractions. In addition, plasma alkaline phosphatase (ALP) and liver microsomal uridine diphosphate glucuronyl transferase (UDPGT) activity were also determined. Administration of DEN/AAF caused an increase in the surface area and number of enzyme-positive foci (both GGT and GSTP) compared with control. Supplementation of vitamin C or aloe vera gel extract to the cancer-induced rats suppressed this increase significantly (P < 0.05; P < 0.001). Increases in liver UDPGT, GGT, and GSTP activities were also observed with cancer induction that were again suppressed with either vitamin C or aloe vera gel supplementation. Plasma GGT in the DEN/AAF rats were determined monthly for the duration of the experiment and found to be reduced as early as 1 mo with aloe vera gel supplementation and 2 mo with vitamin C supplementation. In conclusion, vitamin C and aloe vera gel extract supplementation were found to be able to reduce the severity of chemical hepatocarcinogenesis.
1. The effects of alpha-tocopherol and gamma-tocotrienol on glutathione S-transferase (GST) and gamma-glutamyl transpeptidase (gamma-GT) activities in cultured hepatocytes prepared from rats treated with diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) were investigated. 2. Both the alpha-tocopherol and gamma-tocotrienol treated hepatocytes showed significantly higher (P < 0.05) GST activities than untreated hepatocytes prepared from the carcinogen treated rats in the first 3 days of culture. Treatment with alpha-tocopherol and gamma-tocotrienol generally resulted in a tendency to increase the GST activities above that in the untreated hepatocytes. 3. Treatment with high doses (125-250 microM) of alpha-tocopherol and low doses (12.5-25 microM) of gamma-tocotrienol generally resulted in a significant reduction in gamma-GT activities at 1-3 days. gamma-GT activities are reduced as the dose of alpha-tocopherol and gamma-tocotrienol are increased.