Characteristics of Milk Thistle (Silybum marianum) and the Association with Liver Diseases: A Review of In Vitro and In Vivo Studies

Abstract

Milk thistle (Silybum marianum) belongs to the Asteraceae family. This family is noted for its composite flower heads and its broad distribution. This plant boasts glossy green leaves featuring marbled white veins and vibrant purple blooms and has been used in traditional medicine for over 2,000 years, particularly to treat liver disorders. This study aims to determine the characteristics of milk thistle and its association with liver diseases. The biochemical properties of milk thistle are attributed mainly to its complex mixture of bioactive compounds, particularly flavonolignans, collectively known as silymarin. Silymarin complex includes silybin, isosilybin, silychristin, and silydianin. Another active compound in milk thistle is a flavonoid. Flavonoids comprise taxifolin, quercetin, dihydrokaempferol, kaempferol, apigenin, naringin, eriodyctiol, and chrysoeriol. Furthermore, milk thistle contains macronutrients and micronutrients, making it highly nutritious. Milk thistle and its active components help reduce the incidence of liver disease through their anti-inflammatory, antioxidant, and anti-fibrotic effects. These actions are achieved by regulating the levels and activity of the nuclear factor erythroid 2-related factor 2 (NRF2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), superoxide dismutase (SOD), glutathione peroxidase (GPx), interleukin one beta (IL-1β), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), catalase (CAT), aspartate aminotransferase (AST), bilirubin, cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C).

Main Points: The biochemical properties of milk thistle are largely attributed to bioactive compounds, particularly flavonolignans, collectively known as silymarin. Milk thistle and its active components play a role in decrease the incidence of liver diseases through their anti-inflammatory, antioxidant, and anti-fibrotic effects.