Broad-spectrum antiviral activity of Spatholobus suberectus Dunn against SARS-CoV-2, SARS-CoV-1, H5N1, and other enveloped viruses

The current COVID-19 pandemic caused by SARS-Cov-2 is responsible for more than 6 million deaths globally. The development of broad-spectrum and cost-effective antivirals is urgently needed. Medicinal plants are renowned as a complementary approach in which antiviral natural products have been established as safe and effective drugs. Here, we report that the percolation extract of Spatholobus suberectus Dunn (SSP) is a broad-spectrum viral entry inhibitor against SARS-CoV-1/2 and other enveloped viruses. The viral inhibitory activities of the SSP were evaluated by using pseudotyped SARS-CoV-1 and 2, HIV-1(ADA and HXB2), and H5N1. SSP effectively inhibited viral entry and with EC50 values ranging from 3.6 to 5.1 mu g/ml. Pre-treatment of pseudovirus or target cells with SSP showed consistent inhibitory activities with the respective EC50 value of 2.3 or 2.1 mu g/ml. SSP blocked both SARS-CoV-2 spike glycoprotein and the host ACE2 receptor. In vivo studies indicated that there was no abnormal toxicity and behavior in long-term SSP treatment. Based on these findings, we concluded that SSP has the potential to be developed as a drug candidate for preventing and treating COVID-19 and other emerging enveloped viruses.

Automated summary

The percolation extract of Spatholobus suberectus Dunn (SSP) was found to have broad-spectrum viral entry inhibitory activity against SARS-CoV-1/2 and other enveloped viruses. In vivo studies showed no abnormal toxicity or behavior in long-term SSP treatment. These findings suggest that SSP has the potential to be developed as a drug candidate for preventing and treating COVID-19 and other emerging enveloped viruses.