Abstract
The recent appearance of COVID-19 virus has created a global crisis due to
unavailability of any vaccine or drug that can effectively and
deterministically work against it. Naturally, different possibilities
(including herbal medicines having known therapeutic significance) have been
explored by the scientists. The systematic scientific study (beginning with in
silico study) of herbal medicines in particular and any drug in general is now
possible as the structural components (proteins) of COVID-19 are already
characterized. The main protease of COVID-19 virus is $\rm{M^{pro}}$ or
$\rm{3CL^{pro}}$ which is a key CoV enzyme and an attractive drug target as it
plays a pivotal role in mediating viral replication and transcription. In the
present study, $\rm{3CL^{pro}}$ is used to study drug:3CLpro interactions and
thus to investigate whether all or any of the main chemical constituents of
Tinospora cordifolia (e.g., berberine $\rm{(C_{20}H_{18}NO_{4})}$,
$\beta$-sitosterol $\rm{(C_{29}H_{50}O)}$, choline $\rm{(C_{5}H_{14}NO)}$,
tetrahydropalmatine $\rm{(C_{21}H_{25}NO_{4})}$ and octacosanol
$\rm{(C_{28}H_{58}O))}$ can be used as an anti-viral drug against SARS-CoV-2.
The in silico study performed using tools of network pharmacology, molecular
docking including molecular dynamics have revealed that among all considered
phytochemicals in Tinospora cordifolia, berberine can regulate $\rm{3CL^{pro}}$
protein's function due to its easy inhibition and thus can control viral
replication. The selection of Tinospora cordifolia was motivated by the fact
that the main constituents of it are known to be responsible for various
antiviral activities and the treatment of jaundice, rheumatism, diabetes, etc.