RT Journal Article
SR Electronic
T1 <em>Artemisia annua</em> L. extracts prevent <em>in vitro</em> replication of SARS-CoV-2
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.01.08.425825
DO 10.1101/2021.01.08.425825
A1 M.S. Nair
A1 Y. Huang
A1 D.A. Fidock
A1 S.J. Polyak
A1 J. Wagoner
A1 M.J. Towler
A1 P.J. Weathers
YR 2021
UL http://biorxiv.org/content/early/2021/01/08/2021.01.08.425825.abstract
AB SARS-CoV-2 (Covid-19) globally has infected and killed millions of people. Besides remdesivir, there are no approved small molecule-based therapeutics. Here we show that extracts of the medicinal plant, Artemisia annua L., which produces the antimalarial drug artemisinin, prevents SARS-CoV-2 replication in vitro. We measured antiviral activity of dried leaf extracts of seven cultivars of A. annua sourced from four continents. Hot-water leaf extracts based on artemisinin, total flavonoids, or dry leaf mass showed antiviral activity with IC50 values of 0.1-8.7 μM, 0.01-0.14 μg, and 23.4-57.4 μg, respectively. One sample was &gt;12 years old, but still active. While all hot water extracts were effective, concentrations of artemisinin and total flavonoids varied by nearly 100-fold in the extracts and antiviral efficacy was inversely correlated to artemisinin and total flavonoid contents. Artemisinin alone showed an estimated IC50 of about 70 μM, and antimalarial artemisinin derivatives artesunate, artemether, and dihydroartemisinin were ineffective or cytotoxic at elevated micromolar concentrations. In contrast, the antimalarial drug amodiaquine had an IC50 = 5.8 μM. The extracts had minimal effects on infection of Vero E6 or Calu-3 cells by a reporter virus pseudotyped by the SARS-CoV-2 spike protein. There was no cytotoxicity within an order of magnitude of the antiviral IC90 values. Results suggest the active component in the extracts is likely something besides artemisinin or is a combination of components acting synergistically to block post-entry viral infection. Further studies will determine in vivo efficacy to assess whether A. annua might provide a cost-effective therapeutic to treat SARS-CoV-2 infections.Competing Interest StatementThe authors have declared no competing interest.