Emodin has shown pharmacological effects in the treatment of infection with severe acute respiratory syndrome coronavirus-2, which leads to COVID-19.

Emodin, an anthraquinone compound derived from genus Rheum and Polygonum, significantly blocked the S protein and ACE2 interaction in a dose-dependent manner. It also inhibited the infectivity of S protein-pseudotyped retrovirus to Vero E6 cells. These findings suggested that emodin may be considered as a potential lead therapeutic agent in the treatment of SARS [1].

Natural products can inhibit different coronavirus targets such as S protein (emodin, baicalin) and viral enzymes replication such as 3CLpro (Iguesterin), PLpro (Cryptotanshinone), helicase (Silvestrol), and RdRp (Sotetsuflavone) [2].

1. Emodin blocks the SARS coronavirus spike protein and angiotensin-converting enzyme 2 interaction. Antiviral Res. 2007;74(2):92-101. doi:10.1016/j.antiviral.2006.04.014

2. Natural products for COVID-19 prevention and treatment regarding to previous coronavirus infections and novel studies. Phytother Res. 2021 Feb;35(2):864-876. doi: 10.1002/ptr.6873.


Several molecules, including curcumin, daidzein, diosmin, epigallocatechin-gallate, emodin, hesperidin, kaempferol, lycorine, tanshinone I, taxifolin, rhoifolin, etc. isolated from plants could also be potential drug candidates against COVID-19. Moreover, these could also show promising inhibitory effects against influenza-parainfluenza viruses, respiratory syncytial virus, SARS CoV1, and MERS-CoV [1].

• Preliminary conformational analysis of the receptor (ACE2) binding site of the spike protein is carried out suggesting that while it is somewhat conserved. However compounds like emodin that inhibit SARS entry, apparently by binding ACE2, might also have functions at several different human protein binding sites [2].


1. Potential roles of medicinal plants for the treatment of viral diseases focusing on COVID-19: A review. Phytother Res. 2021 Mar;35(3):1298-1312. doi: 10.1002/ptr.6893.

2. COVID-19 Coronavirus spike protein analysis for synthetic vaccines, a peptidomimetic antagonist, and therapeutic drugs, and analysis of a proposed achilles’ heel conserved region to minimize probability of escape mutations and drug resistance. Comput Biol Med. 2020 Jun;121:103749. doi: 10.1016/j.compbiomed.2020.103749.