Thymoquinone is a major bioactive compound found in the volatile oil of Nigella sativa (black seed). Scientific studies, primarily in vitro and in animal models, have explored its hepatoprotective effects. Several preclinical studies indicate that thymoquinone exhibits antioxidant, anti-inflammatory, and anti-apoptotic activities, which may protect liver tissue from various toxic insults. For example, research has shown that thymoquinone can reduce liver enzyme markers of damage (such as ALT and AST) and histopathological changes in rats exposed to hepatotoxins like carbon tetrachloride and paracetamol. The proposed mechanisms include scavenging of free radicals, inhibition of pro-inflammatory cytokines, and upregulation of antioxidant enzymes like superoxide dismutase and catalase.

While these findings are promising, robust clinical trials in humans are lacking. Most evidence comes from animal studies, and only a few small-scale human studies have evaluated Nigella sativa (with thymoquinone as a component) for liver support. These human studies have suggested some improvement in liver function markers, but the sample sizes and methodologies are limited. Therefore, while there is a scientific basis for considering thymoquinone as a potential hepatoprotective agent, more rigorous clinical research is needed to confirm its efficacy and safety in humans.