Antiviral Potential of Cistus L. against Infectious Bronchitis Virus and SARS-CoV-2

Cistus L. (Cistus) is distributed in Türkiye by 5 species including Cistus creticus L. (C. creticus), Cistus monspeliensis L. (C. monspeliensis), Cistus laurifolius L. (C. laurifolius), Cistus parviflorus L. (C. parviflorus) and Cistus salviifolius L. (C. salviifolius). In this study, antiviral activity of 5 Cistus extracts were investigated against Infectious bronchitis virus (IBV) using the in ovo antiviral activity assay, which measures both embryo viability and agglutination of chicken red blood cells. In further experiments, antiviral potential of C. creticus extract was also examined against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected Vero-E6 cells. In ovo antiviral activity assays displayed that C. parviflorus and C. monspeliensis extracts caused more antiviral activity against IBV-D274 strain than other extracts. Further asssays showed that C. creticus extract led to dose and time dependent antiviral activity against SARS-CoV-2. The results proposed that C. parviflorus and C. monspeliensis extracts might have a potential for the treatment of virus-mediated diseases. Increasing incubation time and concentration of C. creticus extract led to increase of antiviral activity against SARS-CoV-2, which means that C. creticus extract had potent antiviral activity.