**4. Flavonoids and phenolic compounds in COVID-19**

Various studies have shown that the use of some natural substances with antiinflammatory properties can prevent inflammation-induced tissue damage [58–65]. Flavonoids are one of these natural ingredients. Flavonoids and phenolic compounds have significant anti-oxidant, anti-bacterial, anti-cancer, immunomodulatory, and anti-inflammatory abilities [66–71]. Additionally, flavonoids and phenolic compounds exhibit a strong anti-viral capability in multiple pathologies [72–75]. More importantly, flavonoids and phenolic compounds have been determined to exhibit immunomodulatory and anti-viral activities against coronaviruses [76, 77]. Therefore, the anti-viral abilities of flavonoids and phenolic compounds may also apply in the current Covid-19 pandemic. The potentially beneficial role of polyphenols in the Covid-19 pandemic is currently a widely debated topic [78–80]. One of the recommended targets of SARS-CoV-2 treatments is the ACE-2 receptor [81]. Moreover, the biological activity of flavonoids and phenolic compounds predetermines their efficacy in the modulation of the immune and inflammatory pathways of the pathology associated with SARS-CoV-2.
