The Combination of Schisandrol B and Wedelolactone Synergistically Reverses Hepatic Fibrosis Via Modulating Multiple Signaling Pathways in Mice

Hepatic fibrosis represents an important event in the progression of chronic liver injury to cirrhosis, and is characterized by excessive extracellular matrix proteins aggregation. Early fibrosis can be reversed by inhibiting hepatocyte injury, inflammation, or hepatic stellate cells activation, so the development of antifibrotic drugs is important to reduce the incidence of hepatic cirrhosis or even hepatic carcinoma. Here we demonstrate that Schisandrol B (SolB), one of the major active constituents of traditional hepato-protective Chinese medicine, Schisandra sphenanthera, significantly protects against hepatocyte injury, while Wedelolactone (WeD) suppresses the TGF-β1/Smads signaling pathway in hepatic stellate cells (HSCs) and inflammation, the combination of the two reverses hepatic fibrosis in mice and the inhibitory effect of the combination on hepatic fibrosis is superior to that of SolB or WeD treatment alone. Combined pharmacotherapy represents a promising strategy for the prevention and treatment of liver fibrosis.

Schisandrol B and schisandrin B inhibit TGFβ1-mediated NF-κB activation via a Smad-independent mechanism

Aberrant transforming growth factor β1 (TGFβ1) signaling plays a pathogenic role in the development of vascular fibrosis. We have reported that Schisandra chinensis fruit extract (SCE), which has been used as a traditional oriental medicine, suppresses TGFβ1-mediated phenotypes in vascular smooth muscle cells (VSMCs). However, it is still largely unknown about the pharmacologic effects of SCE on various TGFβ1 signaling components. In this study, we found that SCE attenuated TGFβ1-induced NF-κB activation and nuclear translocation in VSMCs. Among the five active ingredients of SCE that were examined, schisandrol B (SolB) and schisandrin B (SchB) most potently suppressed TGFβ1-mediated NF-κB activation. In addition, SolB and SchB effectively inhibited IKKα/β activation and IκBα phosphorylation in TGFβ1-treated VSMCs. The pharmacologic effects of SolB and SchB on NF-κB activation were independent of the Smad-mediated canonical pathway. Therefore, our study demonstrates that SCE and its active constituents SolB and SchB suppress TGFβ1-mediated NF-κB signaling pathway in a Smad-independent mechanism. Our results may help further investigations to develop novel multi-targeted therapeutic strategies that treat or prevent vascular fibrotic diseases.

Comparative Phytochemical Analysis of Chinese and Bay Starvine (Schisandra spp.): Potential for Development as a New Dietary Supplement Ingredient

Schisandra chinensis (Chinese starvine) is a popular dietary supplement with a rich history of use in traditional Chinese medicine. Schisandra glabra (bay starvine) is the only North American representative of the genus, and little is known about its history of traditional use, chemistry, and potential biological activity. In this study, we conducted comparative high-performance liquid chromatography-diode array detector (HPLC-DAD) analysis on S. glabra and S. chinensis fruits. Additional characterization of S. glabra was performed by liquid chromatography-Fourier transform mass spectrometry (LC-FTMS). Quantitative analysis of four bioactive marker compounds revealed that S. glabra does not have statistically higher levels of schisandrin A or schisandrol B than S. chinensis. S. glabra has lower levels of schisandrol A and γ-schisandrin. Total phenolic contents of the two species' fruits were not statistically different. S. glabra had higher total tannin content than S. chinensis. We discuss the relevance of this analytical analysis to the study of S. glabra as a potential dietary supplement ingredient and give specific consideration to the conservation challenges involved in commercially developing a regionally threatened species, even in semicultivated conditions.

Schisandrol B protects against acetaminophen-induced hepatotoxicity by inhibition of CYP-mediated bioactivation and regulation of liver regeneration

Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Schisandra sphenanthera is a traditional hepato-protective Chinese medicine and Schisandrol B (SolB) is one of its major active constituents. In this study, the protective effect of SolB against APAP-induced acute hepatotoxicity in mice and the involved mechanisms were investigated. Morphological and biochemical assessments clearly demonstrated a protective effect of SolB against APAP-induced liver injury. SolB pretreatment significantly attenuated the increases in alanine aminotransferase and aspartate aminotransferase activity, and prevented elevated hepatic malondialdehyde formation and the depletion of mitochondrial glutathione (GSH) in a dose-dependent manner. SolB also dramatically altered APAP metabolic activation by inhibiting the activities of CYP2E1 and CYP3A11, which was evidenced by significant inhibition of the formation of the oxidized APAP metabolite NAPQI-GSH. A molecular docking model also predicted that SolB had potential to interact with the CYP2E1 and CYP3A4 active sites. In addition, SolB abrogated APAP-induced activation of p53 and p21, and increased expression of liver regeneration and antiapoptotic-related proteins such as cyclin D1 (CCND1), PCNA, and BCL-2. This study demonstrated that SolB exhibited a significant protective effect toward APAP-induced liver injury, potentially through inhibition of CYP-mediated APAP bioactivation and regulation of the p53, p21, CCND1, PCNA, and BCL-2 to promote liver regeneration.