Silybin, the Main Active Component of Silybum marianum, Affects Blood Coagulation: An In Vitro Pilot Study

: The health-promoting properties of Silybum marianum have been acknowledged since antiquity. This plant is credited with substantial hepatoprotective properties and is also protective in cardiovascular diseases, diabetes mellitus, and neurodegeneration, mainly for its anti-inflammatory and antioxidant effects. Only a few experimental studies have described the impact of Silybum marianum extract on the blood coagulation process; furthermore, these data are unsatisfactorily fragmented and need to be supplemented to understand the plant’s properties better. The predominant biologically active flavonolignan extracted from Silybum marianum is silybin, a mixture of two diastere-omers, silybin A and silybin B, in approximately equimolar ratio. This study investigated the effect of silybin on the fundamental laboratory parameter for blood coagulation, namely prothrombin time (PT), an assay used to assess the extrinsic and common coagulation pathways. To evaluate the effect of silybin on PT, we prepared three solutions of silybin (Silybin (A + B mixture), PhytoLab GmbH & Co. KG, Vestenbergsgreuth, Germany) in 0.1% dimethylsulfoxide (DMSO, Sigma-Aldrich, Co., St. Louis, MO, USA): 10 µ M, 50 µ M, and 100 µ M. PT was measured on a Coag 4D coagulometer (DIAGON Kft., Budapest, Hungary) using rabbit calcium thromboplastin (Dia-PT, DIAGON Kft., Budapest, Hungary) and control plasma, which is pooled plasma obtained from healthy donors (Dia-CONT, DIAGON Kft., Budapest, Hungary). A total of 10 µ L of silybin solution was added to 40 µ L of plasma; the sample was incubated for two minutes at 37 ◦ C, and then 100 µ L of thromboplastin, pre-warmed to 37 ◦ C, and was added to the mixture. The coagulometer automatically gives the PT result in seconds (s). At the same time, PT was measured in the control plasma both without additional solutions and with the addition of tris-buffered saline (TBS) and 0.1% DMSO (10 µ L of TBS or DMSO + 40 µ L of plasma). Each measurement was