Therapeutic agents can be transformed into reactive metabolites under the action of various metabolic enzymes in vivo and then covalently combine with biological macromolecules (such as protein or DNA), resulting in increasing toxicity. The screening of reactive metabolites in drug discovery and development stages and monitoring of biotransformation in post-market drugs has become an important research field. Generally, reactive metabolites are electrophilic and can be captured by small nucleophiles. Glutathione (GSH) is a small peptide composed of three amino acids (i.e., glutamic acid, cysteine, and glycine). It has a thiol group which can react with electrophilic groups of reactive metabolic intermediates (such as benzoquinone, N-acetyl-p-benzoquinoneimine, and Michael acceptor) to form a stable binding conjugate. This paper aims to provide a review on structure-based reactivity profiles of reactive metabolites with GSH. Furthermore, this review also reveals the relationship between drugs' molecular structures and reactive metabolic toxicity from the perspective of metabolism, giving a reference for drug design and development.

Lapses in the graft-vs.-host disease (GVHD) prophylaxis and side effects of current standard care following allogeneic hematopoietic stem cell transplantation (allo-HSCT) call for novel regimens. Traditional approaches targeting T cells showed limited success in preventing acute GVHD (aGVHD). System medicine showed promising results treating complex diseases such as sepsis and multi-organ dysfunction syndrome (MODS). Adapting established network pharmacology analysis methods, we aimed to develop novel integrative regimens to prevent aGVHD. Our network pharmacology analysis predicted that Xuebijing injection (XBJ) targets a series of key node proteins in aGVHD network. It also unveiled that Salviae miltiorrhizae (Danshen), an herb in Xuebijing formula, which prevented aGVHD in rats, shares five out of six key GVHD node proteins targeted by XBJ. Interestingly, network pharmacology analysis indicated Xuebijing may share multiple aGVHD targets with Cyclosporin A (CsA), a first-line drug for preventing aGVHD in the clinic. Based on current information, we hypothesized that combination of XBJ and CsA may yield superior results in aGVHD prevention than either drug alone. We performed in vitro and in vivo assays to validate the predictions by the network pharmacology analysis. In vitro assays revealed XBJ prevented platelet aggregation and NF-κB nuclear translocation in macrophages. XBJ also promoted angiogenesis in tube-formation assay. Importantly, the combination of CsA and XBJ was effective in rescuing mice subjected to lethal GVHD. XBJ contributed to the rescue through preventing NF-κB nuclear translocation, attenuating inflammation and maintaining viability of macrophages. Overall, network pharmacology is a powerful tool to develop novel integrative regimens. Combination of XBJ and CsA may shed light on preventing aGVHD.

Ethnopharmacological relevance: Plants of the genus Cimicifuga have long been used as an ethnomedicine in China, Europe, and North America for its high medicinal value and health benefits. Their dried rhizomes are widely used for treating wind-heat headache, toothache, aphtha, sore throat, measles, spot poison, archoptosis, and uterine prolapse. In addition, it is used as a dietary supplement for preventing women menopausal symptoms and osteoporosis. Aim of the review: This paper aims to provide up-to-date information on the genus Cimicifuga, including botanical characterization, medicinal resources, traditional medicinal uses, phytochemistry, quality control, pharmacological research as well as the toxicology. The possible structural-activity relationships and molecular mechanisms of the bioactive constituents are discussed in ways that contribute to the structural optimization and preclinical safety assessment for further drug design. Materials and methods: The relevant information on Cimicifuga was collected from scientific databases (such as Google Scholar, PubMed, SciFinder Scholar, Science Direct, CNKI, Baidu Scholar, Web of Science, China Knowledge Resource Integrated Database), Chinese herbal classics, ethnobotanical books, PhD and MSc dissertations, Chinese Pharmacopoeia, published articles in peer-reviewed journals, local magazines, and unpublished materials. In addition, the Plant List (TPL, www.thoplant:ist.org) was also used to validate the scientific names and synonyms of this plant. The literature cited in this review dated from 1953 to 2017. Results: The majority of chemical constituents of this plant include triterpenoid glycosides, phenylpropanoids, nitrogenous compounds, chromones, flavonoids and 4 alpha-methyl steroid. Among them, the primary bioactive constituents are believed to be present in the triterpene glycoside fraction. To date, investigation of seven Cimicifuga spp. plants led to the identification of more than 457 compounds. Years of pharmacological research proved that the crude extracts and certain pure compounds obtained from Cimicifuga exhibited menopausal syndrome-treatment, anti-osteoporosis, antiviral, antitumor, antioxidant and antiangiogenic activities. On the other hand, Cimicifuga plant-induced toxicities of liver, cardiovascular, central and peripheral nervous systems have also been reported. Therefore, safety consideration should be placed into a high priority for herbal medicine Cimicifuga therapy in the early stages of development and clinical trials. Conclusions: This review presents information on botany, medicinal resources, and traditional medicinal history of some Cimicifuga plants. Modern pharmacology researchers have validated many traditional uses of Cimicifuga species. As the quality control and safety assessment of Cimicifuga plants is still incomplete, only a small part of the plant is permitted to be used as medicines. Expansion of medicinal resources in Cimicifuga is urgently needed to enable its full use. Currently research primarily focuses on the triterpenoid glycosides but there are many other types of compounds which may possess new biological activities however the systematic studies of these compounds are lacking. Extensive study is required on Cimicifuga plant before it can be fully used in clinics as a potent drug candidate.