Plants and Surgery: The Protective Effects of Thymoquinone on Hepatic Injury-A Systematic Review of In Vivo Studies

Multimodal treatment concepts including liver transplantation for hepatocellular carcinoma (HCC), extended resection methods and neoadjuvant chemotherapy for colorectal liver metastasis significantly improve patients' outcome. However, surgery-induced hepatic ischemia-reperfusion injury (IRI) and chemotherapy-associated hepatotoxicity result in hepatocellular damage and compromised liver function. Activation of common key pathways in ischemic liver and hepatotoxic injury results in oxidative stress, inflammatory responses and apoptosis causing organ damage. Controlling liver damage before and during surgery is essential for the postoperative outcome. Nigella sativa has a long tradition as a natural remedy. In the essential oil, Thymoquinone (TQ) was identified as the main component and responsible for most of the therapeutic effects. Therefore, this systematic review aimed to summarize the hepatoprotective effects of TQ and its potential suitability to improve surgical outcome by reducing surgical ischemic injury and hepatotoxicity of neoadjuvant chemotherapy. The key findings can be summarized as TQ having strong antioxidant, anti-inflammatory, antifibrotic, anti-/proapoptotic and anticarcinogenic effects. Almost no side effects were reported irrespective of a large dose range, suggesting a wide therapeutic window. These results give rise to the expectation that TQ could evolve to a novel powerful drug to reduce hepatic injury.