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

Abstract

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. Swiss albino mice between 7 and 10weeks old were divided into eight cohorts of five animals each. Treatment groups consisted of a distilled water control, MRV alone (275mg/kg po daily), K2Cr2O7 (12.0mg/kg, single ip injection) +/- MRV pretreatment, NaAsO2 (2.5mg/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. 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. Methanol extract of Rauvolfia vomitoria may therefore ameliorate NaAsO2 and K2Cr2O7-induced toxicities via reduction of oxidative stress and fortification of anti-oxidant system.