On August 1, 2020, the team led by Zifeng Yang from Guangzhou Institute of Respiratory Disease and the SKLRD worked with the team led by Li Fu from Jilin Yatai TCM Innovation Institute to publish online at the journal of Phytomedicine an anti-coronavirus research paper, “Phillyrin,(KD-1) exerts anti-viral and anti-inflammatory activities against novel coronavirus (SARS-CoV-2) and human coronavirus 229E (HCoV-229E) by suppressing the nuclear factor kappa B (NF-κB) signaling pathway”, with Zifeng Yang and Li Fu as the corresponding authors and Dr. Qinhai Ma and assistant researcher Runfeng Li from Guangzhou Institute of Respiratory Disease as the first authors.

Forsythia suspensa (Thunb.) Vahl is a deciduous shrub of the genus forsythia of the family luteolinaceae, which is a commonest medicinal material in TCM and has been included in the Chinese Pharmacopoeia since 1963. With a slightly cold nature and a bitter taste, its effects work on the lungs, heart and small intestines, with pharmacological effects such as clearing heat and detoxification, removing swells and stasis, repelling wind-heat, it is often clinically used in the treatment of acute wind-heat cold. Lignans are the main chemical constituents of the medicine, of which KD-1 is lignan compound with a high content, which is named as an important indicator of quality control of the medicine by the 2010 edition of Chinese Pharmacopoeia. Chinese scholars have proven earlier that KD-1 has a good improvement effect on the expression and pathological changes of inflammatory factors caused by Influenza A virus and LPS infection on the lungs of mice.

Fig. 1 Plaque inhibition effect on Vero E6 cells infected by SARS-CoV-2

Based on the above discoveries, this paper studied the pharmacological activity of KD-1 on another kind of respiratory virus--coronavirus. Zifeng Yang et al have proven that KD-1 can obviously reduce the plaques formed by the common coronavirus HCoV-229E and SARS-CoV-2 in cell replication and can significantly inhibit the nucleic acid expression of inflammatory factors caused by viral infection of cells such as IL-1β, TNF-α, CXCL-10/IP-10, CCL-2/MCP-1 and IL-6. They have further discovered that KD-1 can obviously inhibit the nucleic acid expression of NF-κB p65 and IκBα triggered by the infection of cells by two kinds of coronavirus. The above results have provided a scientific basis for further exploring the effect in vivo of KD-1 in treating coronavirus and mining the potential of Forsythia suspensa in the treatment of coronavirus infection.

Fig. 2 Inhibition effect of KD-1 on the expression of inflammatory factors caused by infection of Huh-7 cell by SARS-CoV-2

Fig. 3 The blocking effect of the NF-κB signal channel of Huh-7 cell activated by HCoV-229E (A) and SARS-CoV-2 (B)