title: In vitro evaluation of antiviral activity of tea seed saponins against porcine reproductive and respiratory syndrome virus.
abstract: BACKGROUND
  Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the major swine pathogens. This virus causes immune suppression and other secondary infections, leading to significant economic losses in the swine industry. Tea seed saponins (TS) are a natural extract from tea seeds with anti-cancer, anti-inflammatory and antiviral activity. In this study, we demonstrated that TS possessed anti-PRRSV activity.
  
  
  METHODS
  MTT assay and trypan blue staining were used to evaluate the cytotoxicity and antiviral ability of TS in cell culture. Apoptosis was measured to assess the safety of TS on Marc-145 cells. Time-of-addition assay, entry inhibition assay and virucidal assay were used to assess the antiviral action of TS. The effect of TS on host cellular gene expression was analysed by real-time PCR. Absolute quantification RT-PCR and western blot were used to study the inhibitory effect of TS on PRRSV N gene and protein expression.
  
  
  RESULTS
  Our results showed that 50% cytotoxic concentrations (CC50) and 50% effective concentration (EC50) of TS were 59.86 ±0.3841 µg/ml and 24.29 ±1.194 μg/ml, respectively. The maximum non-cytotoxic concentration of TS on Marc-145 cells was 30 μg/ml. TS inhibited PRRSV-induced cell apoptosis and effectively inhibited PRRSV replication by reducing the expression of host cellular gene PABP, and significantly inhibited virus N gene/protein expression.
  
  
  CONCLUSIONS
  TS possessed anti-PRRSV activity in vitro and could serve as a potential antiviral drug for PRRSV prevention and control.
authors.affiliation: College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, PR China.
authors.forename: E
authors.initials: E
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Sun
authors.forename: Jun-Xing
authors.initials: JX
authors.lastname: Zhao
authors.forename: Yao-Gui
authors.initials: YG
authors.lastname: Sun
authors.forename: Jian-Gang
authors.initials: JG
authors.lastname: Huang
authors.forename: Hai-Min
authors.initials: HM
authors.lastname: Lei
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Guo
authors.forename: Yuan-Liang
authors.initials: YL
authors.lastname: Hu
authors.forename: Wen-Kui
authors.initials: WK
authors.lastname: Wang
authors.forename: Hong-Quan
authors.initials: HQ
authors.lastname: Li
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology* / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004305:Dose-Response Relationship, Drug; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology* / Q000633:toxicity; D019316:Porcine respiratory and reproductive syndrome virus / Q000187:drug effects* / Q000502:physiology; D012503:Saponins / Q000494:pharmacology* / Q000633:toxicity; D012639:Seeds / Q000737:chemistry*; D013552:Swine; D013662:Tea / Q000737:chemistry*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D010936:Plant Extracts; D012503:Saponins; D013662:Tea; D014764:Viral Proteins