SOURCE:

Faculty: Biosences
Department: Applied Biochemistry

CONTRIBUTORS:

Enemali, M.O;
Udedi, S.C;

ABSTRACT:

The liver is the site for the metabolism of drugs and other xenobiotics and is directly affected by the toxicity of some metabolites, such as N-acetyl-p-benzoquinone imine, from acetaminophen, leading to some liver diseases. Some leafy vegetables have been implicated in the prevention and treatment of these liver diseases, but the veracity or otherwise of this claim has not been well documented. This study was conducted, to establish the protective effect of the aqueous and ethanol leaf extracts of Ocimum canum, Telfeiria occidentalis, Amarranthus viridis, Pterocarpus santalinoides, Vernonia amygdalina and Ocimum gratissimum on acetaminophen-induced acute liver toxicity in albino rats. Proximate and phytochemical compositions were determined using standard methods while antioxidant potentials and the biochemical parameters were determined using spectrophotometer. The hepatoprotective potentials of the leaf extracts were determined, using ninety (90) albino rats which were divided into fifteen (15) groups of six (6) animals each. The normal control received feed and water only, the negative control received feed and water while the standard control received feed, water and a pre-treatment with Silymarin. The other twelve groups received feed, water and pre-treatment with either aqueous or ethanol leaf extract of one of the vegetables. On the eighth (8) day all the animals except the normal control were administered with a 2g/kgbw of acetaminophen and sacrificed after nine (9) hours. Histopathological study on the rats were carried out to determine the integrity of the hepatocytes of the experimental rats, by the method of Haematoxylin and Eosin stain. The leaf of the vegetables had protein and ash contents of 13.26% - 28.88% and 11.12% - 17.77% respectively. Phenol was present in all ethanol extracts in the range of 2.8% - 13.8% but present in only four of the aqueous extracts in the range of 4% - 6.4%. Saponins were present in almost all the extracts but higher in the aqueous. The aqueous extracts showed a concentration dependent increase in their in vitro antioxidant property from 0.03mg/l to 0.5mg/l as against the ethanol extracts which did not show any pattern. The administration of a single dose of 2g/kgbw acetaminophen to the negative control, led to oxidative stress/liver disease/liver damage, evidenced by a marked elevation (p<0.05) of the activity of Alanine aminotransferase (ALT), significantly decreased (p<0.05) Serum albumin concentration, significantly reduced (p<0.05) activity of antioxidant enzymes (Superoxide Dismutase-SOD and Glutathione Peroxidase-GPx) as compared to the normal control. The pre-treatment with 400mg/kgbw of either ethanol or aqueous leaf extracts of the plants protected the livers as seen in the marked reduction (p<0.05) of the activity of ALT with the values between 27.34u/l - 73.4u/l and 41.00u/l - 66.36% respectively as compared to the negative control (117.30±57.50u/l). The activities of SOD in the liver homogenates were raised by the aqueous and ethanol leaf extracts from 0.02±0.01u/mg in the negative control up to a maximum of 0.12±0.17u/mg in ethanol leaf extract of Ocimum gratissimum. The activity of GPx was raised from 115.60±10.03u/mg of the negative control to between 233µ/mg - 391µ/mg and 143µ/mg - 313µ/mg by aqueous and ethanol extracts respectively as compared to that by the standard drug which was 184.60±23.60. The activity of Catalase was raised from moderate to significantly (p<0.05) among the groups pre-treated with either the aqueous or ethanol leaf extracts. The lobular architectures of the hepatocytes of animals pre-treated with these extracts were moderately/well preserved. It was concluded that the leaves, which are rich in protein, ash and bioactive compounds offered protection to the hepatic cells, by reducing the serum activities of ALT, raising the serum albumin concentration, increasing significantly the activities of CAT, SOD and GPx and preserving the hepatic lobular architectural structures. The vegetables can be sources of raw materials for the manufacturing of drugs for liver diseases and other pathological conditions associated with oxidative stress.