SARS‐CoV‐1 Mpro inhibitors were also discovered from medicinal plants. In 2011, Ryu et al. 187  disclosed a range of inhibitors obtained from Torreya nucifera leaves. Of all the isolated chemicals, the biflavone, amentoflavone (138; Figure 33), was identified as a potent noncompetitive inhibitor with an IC50 of 8.3 µM. Docking studies of 138 identified the interactions of Val186 and Gln192 as major sites at the target.