Int J Biol Sci 2022; 18(12):4669-4676. doi:10.7150/ijbs.74676 This issue


Natural tannins as anti-SARS-CoV-2 compounds

Shao-Chun Wang1,2,3,4*✉, I-Wen Chou3*, Mien-Chie Hung1,2,3,4✉

1. Graduate Institute of Biomedical Sciences, College of Medicine, China Medical University, Taichung, Taiwan, 40402
2. Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, 40447
3. Research Center for Cancer Biology, China Medical University, Taichung, Taiwan, 40402
4. Department of Biotechnology, Asia University, Taichung, Taiwan, 41354
*These two authors contributed equally.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Wang SC, Chou IW, Hung MC. Natural tannins as anti-SARS-CoV-2 compounds. Int J Biol Sci 2022; 18(12):4669-4676. doi:10.7150/ijbs.74676. Available from

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Graphic abstract

Tannins are polyphenols enriched in wood, bark, roots, leaves, seeds and fruits of a variety of plants. Over the last two decades, there has been an increasing interest in understanding the biological functions of tannins and their applications as antioxidants, anticancer drugs, and food additives. Since the outbreak of the COVID-19 pandemic, much effort has been devoted to finding an expedient cure. Tannins have been put forward as having possible anti-COVID-19 properties; however, owing to the profuse nature of the structurally diverse derivatives of tannins, the tannin species in the family associated with an indication of anti-COVID-19 have been poorly defined, compounded by frequent terminology misnomers. This article reviews the tannin family in fruits and the current knowledge about the activities of the compounds with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It will aid molecular and cellular biologists in developing natural anti-viral chemicals as means of overcoming the current and future pandemics.