Effects of plant-derived polyphenols on the coronavirus treatment and prevention: a review
Effects of plant-derived polyphenols on the coronavirus treatment and prevention: a review
Mehdi Dehghani Kazemi,1,*
1. Department of Biology, Faculty of Science, University of Zabol, Zabol, Iran
Introduction: Polyphenols are non-flavonoids or flavonoids plant-derived metabolites with wide verities of biological properties including antioxidant, anti-inflammatory, anticancer, antidiabetic, prebiotic, hepatoprotective, neuroprotective and antiviral. This study aims at reviewing the literature concerning to the antiviral potentials of polyphenols in prevention or treatment of COVID-19 infection.
Methods: An extensive literature search was conducted from the onset of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) or the 2019 novel coronavirus at the end of 2019, using various databases including Google Scholar, and Scopus. Using different combinations of several keywords including COVID-19, infection, prevention and polyphenols. A total of 16 papers were selected for conducting this review.
Results: Like other coronaviruses, SARS-CoV-2, which is the seventh coronavirus infecting humans, is a 150–160 nm virus with positive single-stranded RNA, nucleoprotein, capsid, matrix, and S-protein, but unlike other coronaviruses it possesses an extra glycoprotein with acetylesterase and hemagglutination properties. The virus induces a spectrum of manifestations and affects respiratory, gastrointestinal, hematological, nervous, renal, and the immune systems, affecting more than 219 million people with 4.55 million deaths by September tenth 2021. There are several vaccines developed against the virus, while none of them provide complete protection due to consecutive mutations in its genetic material. Currently, only supportive care and non-specific treatment is available for this lethal disease. For these reasons, a complementary treatment or preventive strategy via biologically active natural products is highly necessary. The main protease of SARS CoV-2 is the key enzyme for the virus replication and transcription, thus serves as an important drug target for inhibiting the virus growth inside the hose. A comparison between six polyphenols of Broussonetia papyrifera with two anti HIV drugs (lopinavir and darunavir) against SARS CoV-2 main protease, showed that natural polyphenols are superior in inhibition of protease catalytic activity and halt of the virus replication, suggesting them as promising anti-COVID-19 drugs. Currently, various natural polyphenols from medicinal plants are extensively employed alone or as an adjunct to antiviral drugs against the virus worldwide. However, there are evidences that medicinal plants rich in resveratrol, quercetin, and kaempferol show a high efficacy against SARS-CoV-2, via interfering with the virus replication, inflammation, chemokine production, vascular permeability, and virus-induced apoptosis. These three polyphenols show anti-oxidant, anti-inflammatory and autophagy induction effects synergistically and counteract the virus replication. The phenolic compounds sinigrin and hesperetin extracted from Isatis indigotica root, have also showed anti-SARS-CoV main protease activity. This prohibition has been attributed to floronates, flavonoids, and pseudo-peptides. There are other phenolic compounds counteracting SARS-CoV-2 through interacting with the receptor binding site and catalytic dyad of the main protease including pedunculagin, tercatain, castalin phacelianin, gentiodelphin, cyanodelphin, and tecophilin. The strongest SARS-CoV-2 inhibitors are among florotannin group (8,8′ -Bieckol, 6,6′ -Bieckol, Dieckol) and oligomers of phloroglucin (1,3, 5- trihydroxybenzene) extracted from the algae Ecklonia cava and Sargassum spinuligerum, respectively (Phaeophyceae). A study recommended daily consumption of Rubus idaeus, Rubus fruticosus, Punica granatum and specially Camellia sinensis (black tea) in early stages of the virus infection due to their high content of effective polyphenols against SARS-CoV-2 including Sanguiin H-6, Theaflavin 3,3'-Odigallate, Theaflavin 3-O-gallate, Kaempferol 3-Oglucuronide, Protocatechuic acid 4-Oglucoside, and Punicalagin.
Conclusion: The natural plant derived polyphenols represent a valuable potential for combating the multisystem COVID-19 pathogenesis due to their multi-system, multi-target, anti-inflammatory, antioxidant, antiviral, and immune promotor impacts along with low toxicity at recommended doses. Therefore, the potential Antiviral polyphenolic-based drugs will hopefully constrain the SARS-CoV-2 infection and duplication by mitigating the virus enzymes.