Traditional herbal remedy cuts COVID-19 virus levels by 73%, study finds

A traditional herbal prescription long used to treat hemorrhoid-related inflammation has shown the ability to suppress COVID-19 virus replication, according to new research. In animal experiments, viral protein levels fell by up to about 73%, and survival rates in some infection models rose from zero to 60%.

The Korea Institute of Oriental Medicine announced Tuesday that a research team led by Jin Young-hee of its Herbal Medicine Application Center had confirmed the potential of the herbal formula Euljatang — a traditional prescription for hemorrhoid-related inflammation — to inhibit coronavirus. The team worked jointly with Professor Lee Sang-myung of Chungbuk National University and Professor Kim Tae-hoon of Kyung Hee University's Korean Medicine Hospital.

The research team has received approval from the Ministry of Food and Drug Safety for a clinical trial plan and has moved into the patient-testing phase.

Euljatang is a traditional herbal prescription used to treat inflammation caused by hemorrhoids. To determine whether it could be applied to COVID-19 treatment beyond its conventional use, the team conducted cell and animal experiments and analyzed its mechanism of action.

The researchers first applied Euljatang to cells infected with HCoV-OC43 — one of the viruses responsible for the common cold — as well as SARS-CoV-2, the virus that causes COVID-19, and the Omicron variant.

As a result, the expression of viral RNA and proteins decreased, and cell damage caused by infection was also reduced.

The team also identified the mechanism by which the formula suppresses viral replication. Euljatang was found to inhibit the activity of the viral proteases Mpro and PLpro, as well as RdRp, the RNA polymerase involved in replicating the virus's genetic material.

Antiviral effects were also observed in animal experiments.

When the team administered Euljatang to mice and hamsters infected with the COVID-19 virus and the Omicron variant, viral RNA and protein levels fell by about 53% and 73%, respectively. Lung tissue damage caused by infection also improved.

In some infection models, survival rates climbed from 0 to 60 percent. However, these are animal experiment results, and whether the same therapeutic effects occur in humans must be confirmed through clinical trials.

The team also identified the key compounds responsible for the antiviral effect. Four components — baicalein, liquiritigenin, emodin and rhein — were found to be involved in reducing COVID-19 viral protein expression.

Building on these findings, the research team has registered related patents in South Korea, Japan and Europe, and has received a patent registration decision in the United States as well.

The Ministry of Food and Drug Safety approved a clinical trial plan targeting mild COVID-19 patients with symptoms including sore throat and muscle pain. The team plans to administer Euljatang to actual patients to verify its efficacy and safety. Approval of a clinical trial plan is distinct from authorization to market a treatment.

"This research is significant in that it confirmed Euljatang's potential to inhibit coronavirus in cell and animal experiments and advanced that work to the stage of clinical trials in patients," Jin said. "We will continue to rigorously verify the efficacy and safety of Euljatang through clinical research."

The findings were published online in the Journal of Traditional and Complementary Medicine, an international academic journal in the field of traditional and complementary medicine.