title: Identification of 23-(s)-2-amino-3-phenylpropanoyl-silybin as an antiviral agent for influenza A virus infection in vitro and in vivo.
abstract: It has been reported that autophagy is involved in the replication of many viruses. In this study, we screened 89 medicinal plants, using an assay based on the inhibition of the formation of the Atg12-Atg5/Atg16 heterotrimer, an important regulator of autophagy, and selected Silybum marianum L. for further study. An antiviral assay indicated that silybin (S0), the major active compound of S. marianum L., can inhibit influenza A virus (IAV) infection. We later synthesized 5 silybin derivatives (S1 through S5) and found that 23-(S)-2-amino-3-phenylpropanoyl-silybin (S3) had the best activity. When we compared the polarities of the substituent groups, we found that the hydrophobicity of the substituent groups was positively correlated with their activities. We further studied the mechanisms of action of these compounds and determined that S0 and S3 also inhibited both the formation of the Atg12-Atg5/Atg16 heterotrimer and the elevated autophagy induced by IAV infection. In addition, we found that S0 and S3 could inhibit several components induced by IAV infection, including oxidative stress, the activation of extracellular signal-regulated kinase (ERK)/p38 mitogen-activated protein kinase (MAPK) and IκB kinase (IKK) pathways, and the expression of autophagic genes, especially Atg7 and Atg3. All of these components have been reported to be related to the formation of the Atg12-Atg5/Atg16 heterotrimer, which might validate our screening strategy. Finally, we demonstrated that S3 can significantly reduce influenza virus replication and the associated mortality in infected mice. In conclusion, we identified 23-(S)-2-amino-3-phenylpropanoyl-silybin as a promising inhibitor of IAV infection.
authors.affiliation: Department of Microbiology and Immunology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Dai
authors.forename: Li-Qi
authors.initials: LQ
authors.lastname: Wu
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Xiang-Feng
authors.initials: XF
authors.lastname: Zhao
authors.forename: Qian-Ying
authors.initials: QY
authors.lastname: Wan
authors.forename: Xiao-Xuan
authors.initials: XX
authors.lastname: Chen
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Li
authors.forename: Ge-Fei
authors.initials: GF
authors.lastname: Wang
authors.forename: Kang-Sheng
authors.initials: KS
authors.lastname: Li
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D001343:Autophagy / Q000187:drug effects; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D004285:Dogs; D005786:Gene Expression Regulation; D057166:High-Throughput Screening Assays; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000254:growth & development; D061985:Madin Darby Canine Kidney Cells; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020944:Silybum marianum / Q000737:chemistry*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry*; D010957:Plasmids; D055503:Protein Multimerization / Q000187:drug effects; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D012838:Silymarin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology; D025841:Small Ubiquitin-Related Modifier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D014709:Vero Cells
chemical_list: C587548:23-(s)-2-amino-3-phenylpropanoylsilybin; C466624:ATG12 protein, human; C518959:ATG16L1 protein, human; C502778:ATG5 protein, human; D000998:Antiviral Agents; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D008869:Microtubule-Associated Proteins; D010936:Plant Extracts; D034741:RNA, Small Interfering; D012838:Silymarin; D025841:Small Ubiquitin-Related Modifier Proteins; D020928:Mitogen-Activated Protein Kinases