Hepatoprotective Activity Evaluation

Hepatoprotective evaluation assesses a candidate extract's ability to prevent or reverse chemically induced liver injury, most commonly using the carbon tetrachloride (CCl4)-induced hepatotoxicity model in Wistar rats, in which CCl4 (administered intraperitoneally as a dilute solution in olive oil) is metabolised by hepatic cytochrome P450 to a reactive free radical that initiates lipid peroxidation and centrilobular hepatocellular necrosis. Hepatoprotection is assessed through serum liver enzymes — alanine aminotransferase (ALT), the most liver-specific marker of hepatocellular injury; aspartate aminotransferase (AST); and alkaline phosphatase (ALP), elevated specifically in cholestatic injury — together with serum total bilirubin and total protein, reflecting hepatic synthetic and excretory function. Oxidative stress within liver tissue is assessed biochemically through malondialdehyde (MDA) as a marker of lipid peroxidation and through the activity of endogenous antioxidant enzymes including superoxide dismutase, catalase, and glutathione peroxidase, while histopathological examination of liver sections stained with haematoxylin and eosin provides direct morphological confirmation of hepatocellular necrosis, inflammatory infiltrate, and steatosis, graded using a standardised scoring system. Silymarin, the standardised flavonolignan extract of Silybum marianum (milk thistle), serves as the conventional positive reference hepatoprotective standard against which candidate herbal extracts are benchmarked.