Acute and sub-lethal toxicological evaluation of flavonoid fraction of Monodora myristica Geartn Dunnel seeds

Abstract

This study investigated acute toxicity of flavonoid fraction of Monodora myristica in mice and sub lethal toxicity in rabbits. Powdered seed of M. myristica (312 g) was extracted with 2.5 L of 70% (v/v) ethanol for 24 h followed by concentration under reduced pressure at 40 oC to obtain a brown residue termed ethanolic extract (EE). The EE was subjected to solvent-solvent partitioning with ethyl acetate to obtain the flavonoid fraction (FF). The acute toxicity test involved oral administration of graded doses of FF of M. myristica to six groups of mice. Biochemical changes as a result of sub lethal exposure of FF to rabbits were investigated at 500 mg/kg bwt and 1000 mg/kg bwt for 28 days. The effects of the extract of M. myristica on total protein, albumin, bilirubin, creatinine, urea, as well as the activities on specific marker enzymes (L-alanine and Laspartate aminotransferases, alkaline and acid phosphatases and gamma  glutamyltransferase) were evaluated in the plasma and liver homogenates of rabbits. The histopathological evaluation of the liver, brain, heart, lungsand kidney of rabbits were carried out. FF of M. myristica was observed to be non toxic in mice with LD50 greater than 5000 mg/kg bwt. There were no significant differences (p > 0.05) in the total protein, albumin, bilirubin, creatinine, uric acid, urea levels in the liver and plasma of treated animals. Moreover, some activities of specific marker enzymes such as L-alanine and L-aspartate aminotransferases, acid and alkaline phosphatases and gamma glutamytransferase were not adversely affected. Histopathological findings showed no significant differences between control and the treated groups and revealed that the brain, lungs, heart, liver and kidney tissues of rabbit were not adversely affected.Keywords: Ethanolic extracts (EE), flavonoid fraction (FF), toxicity, Monodora myristica (MM).