Acetonic extract of Vernonia amygdalina (Del.) attenuates Cd-induced liver injury: Potential application in adjuvant heavy metal therapy

Abstract

Exposure to cadmium (Cd), even at low doses, is of serious health concern because it does not undergo metabolic degradation to less toxic metabolite. Liver injury/disease, with a world-wide increasing incidence, is one of the consequences of exposure to Cd toxicity. This study aimed at determining the effects of acetonic extract of Vernonia amygdalina leaf (AEVAL) in a Wistar rat model of Cd-induced liver injury. Phytochemical screening of the extract was carried out and its oral LD₅₀ was determined to guide the choice of therapeutic doses. Thereafter, thirty male Wistar rats were recruited for this study. The experimental groups received 4 weeks oral graded doses of the extract (100, 200 and 400 mg/kg) following Cd-induced liver injury. Cd-induced liver injury (5 mg/kg i.p for 5 consecutive days) was characterized by deleterious alterations in the levels of AST, ALT, ALP, total bilirubin and hepatic total protein (p ˂ 0.05). Also, deleterious alteration of oxidative stress indicators (GSH, SOD and CAT) and lipid peroxidation index (TBARS) was observed in the liver homogenates. Histopathological examination showed evidence of degenerated hepatocytes as well as inflammation with disseminated steatosis. These conditions were significantly attenuated (p ˂ 0.05) following treatment with graded doses of the extract, with the highest dose expressing least therapeutic effects. This study concluded that AEVAL attenuated Cd-induced liver injury and is, potentially, a suitable option in adjuvant therapy for heavy metal toxicity.

Keywords: Cadmium; Liver function biomarkers; Liver injury; Oral LD50; Oxidative stress indicators; Vernonia amygdalina leaf; Wistar rats.

Graphical abstract

Fig. 1

Experimental Protocol. G1 = Group 1 (2 ml/kg of distilled water, both i.p and orally); G2 = Group 2 (First 5 rats = 5 mg/kg Cd; Remaining 5 rats = 5 mg/kg Cd + Recovery); G3 = Group 3 (Cd + 100 mg/kg AEVAL); G4 = Group 4 (Cd + 200 mg/kg AEVAL); G5 = Group 5 (Cd + 400 mg/kg AEVAL); n = number of rats in the group.

Fig. 2

Graph Showing the Effects of AEVAL on Plasma AST Level of Wistar Rats with Cd-induced Liver Injury. Each bar represents mean ± standard error of mean (p < 0.05). * = significantly different from control group; a = significantly different from Cd group; and b = significantly different from Cd + recovery group.

Fig. 3

Graph Showing the Effects of AEVAL on Plasma ALT Level of Wistar Rats with Cd-induced Liver Injury. Each bar represents mean ± standard error of mean (p < 0.05). * = significantly different from control group; a = significantly different from Cd group; and b = significantly different from Cd + recovery group.

Fig. 4

Graph Showing the Effects of AEVAL on Plasma ALP Level of Wistar Rats with Cd-induced Liver Injury. Each bar represents mean ± standard error of mean (p < 0.05). * = significantly different from control group; a = significantly different from Cd group; and b = significantly different from Cd + recovery group.

Fig. 5

Graph Showing the Effects of AEVAL on Plasma Total Bilirubin Level of Wistar Rats with Cd-induced Liver Injury. Each bar represents mean ± standard error of mean (p < 0.05). * = significantly different from control group; a = significantly different from Cd group; and b = significantly different from Cd + recovery group.

Fig. 6

Graph Showing the Effects of AEVAL on Liver Total Protein Level of Wistar Rats with Cd-induced Liver Injury. Each bar represents mean ± standard error of mean (p < 0.05). * = significantly different from control group; a = significantly different from Cd group; and b = significantly different from Cd + recovery group.

Fig. 7

Photomicrographs Showing the Histological Effects of AEVAL on the Liver of Wistar Rats Exposed to Cd Toxicity. Red arrow = peri-portal infiltration by inflammatory cells; Yellow arrow = focal area of steatosis; Black dotted circle = aggregate of inflammatory cells; Black broken arrow = mild distribution of inflammatory cells; Green arrow = mild disseminated steatosis.