Antioxidant, hepatoprotective and ameliorative potentials of aqueous leaf extract of Gazania krebsiana (Less.) against carbon tetrachloride (CCl₄)-induced liver injury in Wistar rats

Abstract

Gazania krebsiana (Less.), a member of Asteraceae family, is locally used in the treatment of various ailments mostly among the Basotho tribe of eastern Free State Province, South Africa. The study examines the antioxidant and hepatoprotective potentials of the plant extract on feed and water intake, biochemical parameters such as alanine transaminase (ALT), aspartate transaminase (AST), catalase (CAT), glutathione peroxidase (GP), lipid peroxidation and organ histology. Various concentrations (1.56–25 µg/ml) of aqueous leaf extract of G. krebsiana (ALEG) were tested in in vitro assays. Hepatic injury was induced in the rats by administering 1 ml/kg body weight (BW) CCl₄ in olive oil except in the control group. The effects of treatment with 125, 250 and 500 mg/kg ALEG was investigated in vivo during the 15-day study. Water extract exhibited the best activity against four of the six tested free radicals with an IC₅₀ of 3.32 ± 0.06, 5.00 ± 0.06, 0.60 ± 0.04 and 0.70 ± 0.10 µg/ml in 1,1-diphenyl-2-picryl hydrazyl (DPPH), metal chelating, superoxide anion and 2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, respectively, when compared with standards. Pre- and post-treatment with different concentrations of ALEG significantly (p<0.05) attenuated the elevated serum activities of AST, ALT and thiobarbituric acid reactive substances (TBARS) levels while increasing the activities of CAT and GP. The histopathological micrographs revealed extensive liver damage characterised by vacuolar as well as severe necrosis with cytoplasmic degeneration in the hepatotoxic and pre-treatment groups, however, such liver damages were not observed in the ALEG-treated groups. The results proved the hepatoprotective potential of ALEG versus CCl₄-induced oxidative stress.

Keywords:

• antioxidants
• Gazania krebsiana
• hepatoprotective
• liver injury
• oxidative stress

ACKNOWLEDGEMENTS

The authors acknowledge Dr O.T. Ojuromi, Dr T. Ogundajo, Dr (Mrs) R. Daudu, Mr S. Sabiu and Ms G. Mehanke for the thorough reading of the manuscript, animal handling as well as taking care of the animal house, respectively. The authors also gratefully thank the research committee of the University of the Free State, Qwaqwa Campus for financing the study.