Sub-acute toxicity study on the aqueous extract of <i>Albizia zygia</i> stem bark

Abstract

Albizia zygia DC (Fabaceae) is widely used in herbal medicine for the treatment of bronchial diseases, fever (including malaria), diarrhea, sores, wounds and toothache. This study was aimed at determining the sub-acute toxicity of the aqueous extract of Albizia zygia stem bark. The sub-acute toxicity was evaluated after administering daily oral doses of 100, 200 and 500 mg/kg of extract for 42 days to rats. Morphological (body weight and organ weight indices), haematological {white blood cell (WBC), red blood cell (RBC), haemoglobin, haematocrit, and platelet counts}, biochemical {alanine aminotransferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP), total protein, total bilirubin (TB), creatinine, urea} and histopathological parameters were assessed using standard procedures. There was no mortality up to the highest dose of 5000 mg/kg in both mice and rats on oral acute administration of A. zygia. Administration of A. zygia (500 mg/kg/day) for 42 days caused a significant (p<0.05) increase in WBC count, decrease in creatinine and no significant changes in relative organ weights or serum concentrations of ALT, ALP, TB, albumin and urea in the treated rats compared to the control. Histologic analysis of the various organs showed mild activation of the lymphocytes of the lungs and the liver, sinus histiocytes of the spleen and mild interstitial congestion in the kidneys, indicating activation of the local immune system of the lungs, liver, kidney and spleen. The results of the study suggest that the aqueous extract of Albizia zygia stem bark can be considered relatively safe on sub-acute exposure.

Keywords: Albizia zygia; Acute toxicity; Histopathology; Spleen