ABSTRACT

Callichilia subsessilis (Apocynaceae) is a medicinal plant usually seen along the coast of West Africa. The hepatoprotective and curative effect of the methanol fraction of C. subsessilis (MFCS) leaves in rats were evaluated. The leaves were extracted with 80% methanol for 48 hrs using cold maceration method. The hepatoprotective and curative activities of MFCS at 12.5, 25 and 50 mg/kg and Silymarin at 50 mg/kg was evaluated using carbon tetrachloride and paracetamol as hepatotoxic agents. Functionality of the liver was assessed using AST, ALP, ALT, total protein, bilirubin, albumin, cholesterol and Triglyceride assays. The antioxidant activity was determined using both in vitro (2-2 diphenyl-1-picrylhydrazyl photometric assay and Ferric Reducing Antioxidant Power) and in vivo (Malondialdehyde, Catalase and Superoxide dismutase) assays. The animals showed no signs of toxicity or death in acute toxicity test with LD50 of the extract >2000 mg/kg. Seventy-two (72) mature albino Wister rats were randomly distributed into 6 groups (A-F) in two batches. Groups A served as the normal control (received distilled water only), group B served as negative control and received distilled water and no hepatoprotective agent, group C was the positive control and received Silymarin (50 mg/kg) while Groups D,E & F were the treatment groups at 12.5, 25 and 50 mg/kg body weight of the extract, respectively. Batch 1 was given 20% CCl4 in liquid paraffin while batch 2 received 2000 mg/kg of Paracetamol as their hepatotoxic agents in Groups B-F. After 10 days pretreatment with Silymarin and MFCS extract, three rats from each group were sacrificed after 48 hrs of intoxication and the remaining animals kept for 5 more days for the antihepatotoxic study.  Statistical analysis was performed using One Way analysis of Variance and significant means separated using Tukey’s multiple comparism tests. The extract (12.5 and 25 mg/kg) and Syrimarin produced a significant (p < 0.05) dose-dependent decrease in the levels of ALT, AST and ALP when compared with the negative control group. There was no significant (p > 0.05) difference in the serum levels of Total protein, Albumin and bilirubin across the groups. The cholesterol, triglyceride and HDL-C levels of the treatment groups were significantly (p < 0.05) lower than the negative control group in the antihepatotoxic model. MFCS and Silymarin showed a dose-dependent decrease in the MDA and SOD levels. The catalase level of the antihepatotoxic model showed a significant (p < 0.05) increase in the negative control group when compared to the treatment group in Paracetamol model. The extract (25-400 μg/ml) produced a concentration dependent increase in antioxidant activity and equipotent value at 200 and 400 μg/ml in 2-2 diphenyl-1- picrylhydrazyl (DPPH) assay. The FRAP value showed an increase in a concentration-dependent manner. The study demonstrated that the methanolic fraction of C. subsessilis have a potent hepatoprotective effect, especially the lower doses (12.5 and 25 mg/kg), probably by reducing oxidative stress, as evidenced by the in vivo and in vitro assays and supported by the histopathological studies.