Identification of bioactive compounds in ethylacetate fraction of Tapinanthus bangwensis leaves that ameliorate CCl4-induced hepatotoxicity in Wistar rats

The pharmacological effects of medicinal plants are due to the presence of certain chemical compounds present in them. Previous studies have shown that crude extracts of Tapinanthus bangwensis (T. bangwensis) possess hepatocurative potential. However, the present study aims on evaluating the antioxidant activity as well as identifying the chemical compounds in ethylacetate fraction of T. bangwensis that ameliorate carbon tetrachloride-induced hepatotoxicity in Wistar rats. Six subfractions of ethylacetate fraction were obtained by column chromatography. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazine (DPPH), biochemical assay determined by spectrophotometry, and compound elucidation by liquid chromatography–mass spectroscopy (LC-MS) analysis. The DPPH result shows that subfraction F0 exhibited the strongest antioxidant activity followed by F4 while F1 exhibited the lowest. Oral administration of 100 mg/kg body weight of the subfractions of ethylacetate fraction of T. bangwensis increases superoxide dismutase and catalase activities and also glutathione level and decreases malondialdehyde level compared to the positive control group. Subsequently, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total bilirubin, and conjugated bilirubin were reduced while albumin and total protein levels increased compared to the positive control group. However, there were no significant differences between the positive control group and the group induced and treated with the subfractions at p < 0.05. The histopathology study shows normal hepatocyte distribution with no fat deposit in the induced and treated groups while fatty liver was observed in the positive group. The anti-hepatotoxic effect was higher in F4 than in other subfraction treated groups. Hence, the LC-MS analysis of F4 reveals the presence of 8-hydroxyluteolin-8-glucoside, Avicularin, Fisetin-7-glucoside, Isoscutellarein-7-xyloside, and Isovitexin, respectively, and has been reported to exhibit antioxidant and hepatocurative activities. It can be concluded that the hepatocurative effect could be due to the chemical compounds identified above.