Establishment of a Method for Determination of Anemoside B4 Content in Pulsatilla Water Extract

[Objective] This study aimed to establish a new method for determination of anemoside B4 content in pulsatilla water extract. [Method] Using acetonitrile-water （28：72） as the mobile phase, the high performance liquid chromatography, equipped with UV detector, was used to determine the anemoside B4 content in pulsatilla water extract. [Result] In the concentration range of 300-800 μg/ml, anemoside B4 content showed a good linear relationship with peak area. The average recovery of anemoside B4 was 98.12% （n=-6; RSD=-1.37%）. [Conclusion] The established method meets the requirements by methodology, and it can be used to determine the anemoside B4 content in pulsatilla water extract.

Anemoside B4 inhibits SARS-CoV-2 replication in vitro and in vivo

Objective: Anemoside B4(AB4), the most abundant triterpenoidal saponin isolated from Pulsatilla chinensis, inhibited influenza virus FM1 or Klebsiella pneumoniae-induced pneumonia. However, the anti-SARS-CoV-2 effect of AB4 has not been unraveled. Therefore, this study aimed to determine the antiviral activity and potential mechanism of AB4 in inhibiting human coronavirus SARS-CoV-2 in vivo and in vitro.Methods: The cytotoxicity of AB4 was evaluated using the Cell Counting Kit-8(CCK8) assay. SARS-CoV-2 infected HEK293T, HPAEpiC, and Vero E6 cells were used for in vitro assays. The antiviral effect of AB4 in vivo was evaluated by SARS-CoV-2-infected hACE2-IRES-luc transgenic mouse model. Furthermore,label-free quantitative proteomics and bioinformatic analysis were performed to explore the potential antiviral mechanism of action of AB4. Type Ⅰ IFN signaling-associated proteins were assessed using Western blotting or immumohistochemical staining.Results: The data showed that AB4 reduced the propagation of SARS-CoV-2 along with the decreased Nucleocapsid protein(N), Spike protein(S), and 3C-like protease(3CLpro) in HEK293T cells. In vivo antiviral activity data revealed that AB4 inhibited viral replication and relieved pneumonia in a SARS-CoV-2 infected mouse model. We further disclosed that the antiviral activity of AB4 was associated with the enhanced interferon(IFN)-β response via the activation of retinoic acid-inducible gene Ⅰ(RIG-1) like receptor(RLP) pathways. Additionally, label-free quantitative proteomic analyses discovered that 17 proteins were significantly altered by AB4 in the SARS-CoV-2 coronavirus infections cells. These proteins mainly clustered in RNA metabolism.Conclusion: Our results indicated that AB4 inhibited SARS-CoV-2 replication through the RLR pathways and moderated the RNA metabolism, suggesting that it would be a potential lead compound for the development of anti-SARS-CoV-2 drugs.

Proteomic changes in rat kidney injured by adenine and the regulation of anemoside B4

Adenine is commonly used to establish the animal models for chronic kidney injury and its renal interstitial fibrosis. As an endogenous substance, adenine-induced kidney damage has not yet been fully studied and elucidated, except for inflammatory reaction. Here we analyzed the proteomics of kidney of rats after adenine overloading using LS-MS/MS assay, and observed the role of anemoside B4(B4). The results showed that adenine could down-regulate 285 proteins and up-regulate 164 proteins in rat kidney tissue compared with the normal group. Down-regulated proteins mainly affected related pathways, such as energy metabolism, while up-regulated proteins affected inflammatory response pathways and metabolic pathways. B4 could significantly reverse the down-regulation of about 40 proteins, which were involved in mitochondria, redox processes, extracellular exosomes, acetylation and other signaling pathways. Simultaneously, B4 could inhibit the up-regulation of five proteins caused by adenine, which were involved in cell cycle, oocyte meiosis, PI3 K-Akt and other signaling pathways. Further experimental results of mRNA expression using real-time PCR assay supported the proteomic analysis. Therefore, we proposed that the damage of rat kidney caused by adenine was more complicated, not only with an inflammatory reaction, but also with extensive effects to various metabolic processes in the body. This work provided a valuable clue for comprehensive understanding of adenine-induced renal damage.