Medicinal herbal extracts of Sophorae radix, Acanthopanacis cortex, Sanguisorbae radix and Torilis fructus inhibit coronavirus replication in vitro.
BACKGROUND
Cimicifuga rhizome, Meliae cortex, Coptidis rhizome and Phellodendron cortex have been previously shown to exhibit anti-coronavirus activity. Here, an additional 19 traditional medicinal herbal extracts were evaluated for antiviral activities in vitro.


METHODS
A plaque assay was used to evaluate the effects of 19 extracts, and the concentration of extract required to inhibit 50% of the replication (EC(50)) of mouse hepatitis virus (MHV) A59 strain (MHV-A59) was determined. The 50% cytotoxic concentration (CC(50)) of each extract was also determined. Northern and western blot analyses were conducted to evaluate antiviral activity on viral entry, viral RNA and protein expression, and release in MHV-infected DBT cells.


RESULTS
Sophorae radix, Acanthopanacis cortex and Torilis fructus reduced intracellular viral RNA levels with comparable reductions in viral proteins and MHV-A59 production. The extracts also reduced the replication of the John Howard Mueller strain of MHV, porcine epidemic diarrhoea virus and vesicular stomatitis virus in vitro. Sanguisorbae radix reduced coronavirus production, partly as a result of decreased protein synthesis, but without a significant reduction in intracellular viral RNA levels. The EC(50) values of the four extracts ranged from 0.8 to 3.7 microg/ml, whereas the CC(50) values ranged from 156.5 to 556.8 microg/ml. Acanthopanacis cortex and Torilis fructus might exert their antiviral activities in MHV-A59-infected cells by inducing cyclooxygenase-2 expression via the activation of extracellular signal-related kinase (ERK) and p38 or ERK alone, respectively.


CONCLUSIONS
Sophorae radix, Acanthopanacis cortex, Sanguisorbae radix and Torilis fructus might be considered as promising novel anti-coronavirus drug candidates.
Kim
Hye-Young
HY
Department of Microbiology, Ajou University School of Medicine, Suwon, South Korea.
Eo
Eun-Young
EY
Park
Hyun
H
Kim
Youn-Chul
YC
Park
Sun
S
Shin
Ho-Joon
HJ
Kim
Kyongmin
K
D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D017934:Coronavirus / Q000187:drug effects / Q000502:physiology; D007887:Fabaceae / Q000737:chemistry*; D051379:Mice; D006517:Murine hepatitis virus / Q000187:drug effects* / Q000502:physiology; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D014709:Vero Cells; D014779:Virus Replication / Q000187:drug effects*
D010936:Plant Extracts