Toxicity of triptolide and the molecular mechanisms involved

Triptolide (TP), a major active and toxic ingredient isolated from the traditional Chinese herb Tripterygium wilfordii Hook f. (TWHF). A widespread application of TP raises the question on the safety of its use in clinical settings. The metabolism of TP is mediated by hepatic cytochrome P450s, and a strong correlation exists between TP toxicity and CPY3A. Toxicity of TP and the molecular mechanisms of its toxic effects have been studied in recent years. Studies have demonstrated that TP exposure results in injury of various organs, including the liver, kidney, testes, ovary, and heart in animals and even in humans, according to clinical case reports. Moreover, on the cellular level, TP has been reported to be associated with diverse toxic effects, encompassing membrane damage, mitochondrial disruption, metabolism dysfunction, endoplasmic reticulum stress, oxidative stress, apoptosis and autophagy. This review presents an overview of the current findings related to TP toxicity with an emphasis on biological targets and the molecular mechanisms that may be involved, thus providing a systematic understanding of the mechanisms by which TP affects cells and tissues in vitro and in vivo.