Attenuation of potassium dichromate and sodium arsenite toxicities by methanol extract of Rauvolfia vomitoria in mice.

OBJECTIVES: Exposure to arsenic and hexavalent chromium is a major public health concern especially in the developing part of the world and there is paucity of information on reliable treatment modalilities. It is in this regard that this study evaluates the efficacy of methanol leaf extract of Rauvolfia vomitoria (MRV) when used as pretreatment agent against potassium dichromate (K2Cr2O7) and sodium arsenite (NaAsO2) exposure. METHODS: Swiss albino mice between 7 and 10 weeks old were divided into eight cohorts of five animals each. Treatment groups consisted of a distilled water control, MRV alone (275 mg/kg po daily), K2Cr2O7 (12.0 mg/kg, single ip injection) +/- MRV pretreatment, NaAsO2 (2.5 mg/kg, single ip injection) +/- MRV pretreatment, Na2AsO2 + K2Cr2O7 +/- MRV pretreatment. MRV was given for seven consecutive days, while K2Cr2O7 and NaAsO2 were injected on day seven of the experiment. The frequency of micronucleated polychromatic erythrocytes (mPCEs) was determined in bone marrow cells, while aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were assessed in the plasma. Hepatic glutathione (GSH), malondialdehyde (MDA), catalase (CAT) and glutathione-S-transferase (GST) levels were also determined. RESULTS: The NaAsO2 and K2Cr2O7 significantly (p<0.05) increased mPCE formation, AST, ALT, and CAT when compared with the control. Simultaneous exposure to NaAsO2 and K2Cr2O7 further increased the levels of the markers. Furthermore, GSH and GST were significantly reduced by NaAsO2 or K2Cr2O7 or their combination. Pretreatment with MRV reversed the markers towards that of control. CONCLUSIONS: Methanol extract of Rauvolfia vomitoria may therefore ameliorate NaAsO2 and K2Cr2O7-induced toxicities via reduction of oxidative stress and fortification of anti-oxidant system.

Potassium Dichromate Toxicities: Protective Effect of Methanol Extract of Corchorus olitorius in Albino Rats.

Exposure to hexavalent chromate compounds such as other human carcinogens is unavoidable in the developing countries of the world. Research efforts are being directed toward minimizing exposure to them, intercepting their activity in vivo, and/or prophylaxis. The present study therefore evaluates the effect of methanol extract of the leafy vegetable, Corchorus olitorius (MECO), against potassium dichromate (K2Cr2O7)-induced toxicities. Negative control animals were fed distilled water, while the positive control rats received 12 mg/kg body weight K2Cr2O7 once a week for 6 weeks. Test rats were exposed daily to 25, 50, and 100 mg/kg body weight MECO alone for 6 weeks and 12 mg/kg body weight of K2Cr2O7 once a week for 6 weeks before sacrifice. The frequency of micronucleated polychromatic erythrocytes (mPCEs) was monitored in bone marrow cells, while induction of aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine levels, and hematological parameters were assessed in the plasma. The phytochemical analysis of MECO was also carried out. K2Cr2O7 significantly (P < .05) increased the levels of mPCEs, AST, ALT, creatinine, total white blood cells, and lymphocytes compared with the control. The percentage pack cell volume and neutrophils were, however, reduced. In contrast, MECO at different doses restored the markers toward the levels of the negative control. MECO is rich in flavonoids, saponins, anthraquinones, terpenoids, and phenols, and they might be responsible for the protective effect observed in this study. Our results suggest that MECO has a promising potential in the treatment/management of chromate-induced toxicities.

Comparative hepatotoxicity and clastogenicity of sodium arsenite and three petroleum products in experimental Swiss Albino Mice: the modulatory effects of Aloe vera gel.

Petroleum products (PPs) consist of complex chemical mixtures, mainly hydrocarbons. Their composition varies considerably with source and use. Inappropriate manual handling and use of PPs, in countries like Nigeria, results in excessive skin contact with the possibility of hazard to health. There has been inadequate evidence to classify diesel, kerosene and hydraulic oil as human carcinogens and there is limited evidence for their toxicity and carcinogenicity in experimental animals. We compared the hepatotoxicity and clastogenicity of diesel, petrol or hydraulic oil with that of sodium arsenite (Na(2)AsO(2)) in mice. Our findings showed that these PPs are capable of inducing gamma-glutamyl transferase (gammaGT) activity in the serum and liver to levels comparable with that induced by Na(2)AsO(2). Mice treated with individual PPs have elevated mean liver and serum gammaGT at levels that are significantly different from the values observed for the negative control group. Also, the individual PPs alone have micronuclei formation induction activity similar to Na(2)AsO(2). We found that treatment with Aloe vera gel before the PPs significantly reduced mean liver and serum gammaGT, and the mean number of micronuclei scored when compared with groups administered each of the PPs alone, supporting the presence of hepatoprotective components in Aloe vera.

Exposure of laboratory mice to domestic cooking gas: implications for toxicity.

The ability of domestic cooking gas to induce hepatotoxicity and clastogenicity in mice was studied. The mice were exposed to domestic gas for twenty-one days at doses of 100 mg/kg, 200 mg/kg and 300 mg/kg respectively. The positive control group of mice were given sodium arsenite intraperitoneously at a dose of 2.5 mg/kg body weight. While the negative control group had only distilled water, sodium arsenite significantly (p < 0.05) induced the formation of micronucleated polychromatic erythrocytes (mPCEs), serum and liver gamma glutamyl transferase (gammaGT) and alkaline phosphatase (AP) activities respectively as compared with the observations made in the negative control group. Similarly, the domestic gas significantly (p<0.05) induced mPCEs formation, serum and liver, gammaGT and AP activities. The degree of induction was in the order of 100 mg/kg < 200 mg/kg < 300 mg/kg. However, when compared with the positive control group, the domestic cooking gas at the tested doses was not as potent as sodium arsenite in its ability to induce enzyme activity and mPCEs formation. Limited histopathological analysis of liver samples from treated and untreated mice showed distended blood vessels, necrosis and hepatocellular degeneration in the groups treated with high doses of domestic gas or sodium arsenite as compared with the untreated group. Our findings suggest that the domestic cooking gas has some degree of clastogenic and hepatotoxic activities in mice. Health risks may therefore be associated with long-term occupational and/or domestic exposure in humans.