Affiliations 

  • 1 Department of Biotechnology & Genetic Engineering, University of Development Alternative, Lalmatia, Dhaka-1207, Bangladesh
  • 2 School of Allied Health Sciences, World Union for Herbal Drug Discovery (WUHeDD), and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Nakhon Si Thammarat 80160, Thailand
  • 3 CICECO - Aveiro Institute of Materials and Department of Medical Sciences, University of Aveiro, Aveiro 3810, Portugal
  • 4 School of Pharmacy, University of Nottingham Malaysia Campus, Semenyih 43500, Selangor Darul Ehsan, Malaysia
Trop Biomed, 2021 Sep 01;38(3):360-365.
PMID: 34508344 DOI: 10.47665/tb.38.3.079

Abstract

COVID-19, caused by the SARS-CoV-2 virus, can lead to massive inflammation in the gastrointestinal tract causing severe clinical symptoms. SARS-CoV-2 infects lungs after binding its spike proteins with alveolar angiotensin-converting enzyme 2 (ACE2), and it also triggers inflammation in the gastrointestinal tract. SARS-CoV-2 invades the gastrointestinal tract by interacting with Toll-like receptor-4 (TLR4) that induces the expression of ACE2. The influx of ACE2 facilitates cellular binding of more SARS-CoV-2 and causes massive gastrointestinal inflammation leading to diarrhea. Diarrhea prior to COVID-19 infection or COVID-19-induced diarrhea reportedly ends up in a poor prognosis for the patient. Flavonoids are part of traditional remedies for gastrointestinal disorders. Preclinical studies show that flavonoids can prevent infectious diarrhea. Recent studies show flavonoids can inhibit the multiplication of SARS-CoV-2. In combination with vitamin D, flavonoids possibly activate nuclear factor erythroid-derived-2-related factor 2 that downregulates ACE2 expression in cells. We suggest that flavonoids have the potential to prevent SARS-CoV-2 induced diarrhea.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.