Silibinin induces the generation of nitric oxide in human breast cancer MCF-7 cells.

Increasing research has concentrated on the anti-tumour efficacy of silibinin, a flavonolignan that is clinically used as an hepatoprotectant. However, previous work has found that silibinin-induced apoptosis is accompanied by protective superoxide (O(2)*-) generation in MCF-7 cells. This study further reports the formation of reactive nitrogen species (RNS) in the same system. It finds that silibinin induces nitric oxide (*NO) generation in a time- and concentration-dependent manner. Moreover, the results support that there exists an inter-regulation pattern between RNS and reactive oxygen species (ROS) generation. In addition, silibinin is also found to induce RNS and ROS generation in the isolated populations of mouse peripheral blood mononuclear cells (PBMCs) and a simple in vivo model of Caenorhabditis elegans.