Solanum fastigiatum is a medicinal plant widely distributed in the south of Brazil and has been used mainly to treat hepatitis, spleen disorders, uterine tumors, irritable bowel syndrome and chronic gastritis. The present research was aimed to evaluate the potential antioxidant and hepatoprotective activity of aqueous extracts of leaves using in vitro and in vivo models to validate the folkloric use of the plant.

Antioxidant activity was evaluated by different assays, including thiobarbituric acid reactive species (TBARS), total antioxidant, 2,2-diphenlyl-1-picrylhydrazyl (DPPH) radical and metal ion-chelating activities. The hepatoprotective activity of the aqueous extracts was studied on mice liver damage induced by paracetamol (250mg/kg) by monitoring biochemical parameters.

The extract showed inhibition against TBARS, induced by 10μM FeSO₄ and 5μM sodium nitroprusside in rat liver, brain and phospholipid homogenates from egg yolk. The plant exhibited strong antioxidant activity in the DPPH (IC₅₀, 68.96±1.25μg/ml) assay. The aqueous extract also showed significant hepatoprotective activity that was evident by enzymatic examination and brought back the altered levels of TBARS, non-protein thiol and ascorbic acid to near the normal levels in a dose dependent manner. Acute toxicity studies revealed that the LD₅₀ value of the extract is more than the dose 4g/kg body weight of mice.

The results indicate that this plant possesses potential antioxidant and hepatoprotective properties and has therapeutic potential for the treatment of liver diseases.