Repurposing existing compounds for COVID-19 research is an area of study that has exploded. Antiviral therapy, cell therapy, immunotherapy and herbal medicines have shown variable efficacy. A large number of clinical trials for potential COVID-19 compounds are underway. The coronavirus SARS-CoV-2 infects the endothelium and causes immune cell recruitment that results in extensive endothelial dysfunction and apoptosis. These manifestations make the blood more viscous and result in thrombus formation.
Artemisinin and piperaquine (AP) is a new-generation artemisinin combination therapy-based antimalarials. Artemisinin was isolated from Artemisia annua L in 1972 by Youyou Tu at the Chinese Academy of Traditional Chinese Medicine. This antimalarial compound and its derivatives are not only potent antimalarials but also have antiviral properties. It is reported to reduce the proliferation of the Hepatitis B, Hepatitis C, and HIV viruses. Artemisinin and its derivatives have saved millions of lives across the globe, especially in developing world.
Piperaquine is a bisquinoline antimalarial compound. It was synthesized in the 1960s and used in China and Indochina as for the following 20 years. When piperaquine-resistant strains of Plasmodium falciparum emerged, along with the development of Artemisinin derivatives, its popularity declined during the 1980s. However, it was rediscovered by Chinese scientists when it was found that it was suitable in combination with Artemisinin derivative.
AP was used in a small clinical trial in China. In patients with mild-to-moderate COVID-19, the time to reach undetectable SARS-CoV-2 was significantly shorter in the AP group than in the control group. The study found that AP shortened the time the virus remained in the body. The mechanisms of how AP is improving the health of patients with COVID-19 is still being investigated.
References
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Hou L et al (2016) Immune suppressive properties of artemisinin family drugs. Pharmacol Ther 166:123-7. PMID: 27411673. Link
Li G et al (2021) Safety and efficacy of artemisinin-piperaquine for treatment of COVID-19: an open-label, non-randomised and controlled trial. Int. J. Antimicrob. Agents 57(1):106216 doi:10.1016/j.ijantimicag.2020.106216. Link