In Vitro study of several plant extracts, showing strong inhibition of SARS-CoV-2 3CLpro activity by turmeric rhizomes. Commercial curcumin also inhibited 3CLpro activity, but did not fully account for the inhibitory effect of turmeric rhizomes extracts, suggesting that other components of the turmeric extract also play a main role in inhibiting 3CLpro activity.
Guijarro-Real et al., 6/29/2021, peer-reviewed, 5 authors.
In Vitro studies are an important part of preclinical research, however results may be very different in vivo.