TWiV covers trials of hydroxychloroquine and convalescent plasma therapy for COVID-19, and answers listener questions on blood tests for antibodies, cross-protection among coronaviruses, acquiring infection from food or the gas pump, face masks containing copper, and much more.
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Quercetin: an alternative to chloroquine ?
Increasing the intracellular Zn++ concentrations can inhibit SARS-COV RNA-dependent RNA polymerase (RdRp) (1). As choloroquine (CQ) and hydroxychloroquine (HCQ) are both zinc ionophores this may be one of the mechanisms by which these compounds act to inhibit RNA viral replication.
However CQ and HCQ have side effects such as QT prolongation and hepatotoxicity which can limit its use.
Quercetin is a flavonoid found in many fruits and vegetables, notably in elderberries (Sambucus nigra)
Studies that have used commercial elderberry extracts such as Sambucol, have demonstrated efficacy against influenza viruses (3, 4, 5,6)
Similar to CQ and HCQ, quercetin is a zinc ionophore (7).
Also quercetin exhibits immunomodulatory effects by increasing cytokine production (8)
Perhaps Dr. Griffin and fellow TWiV team members could speak to this.
Thank You All
1. te Velthuis AJW, van den Worm SHE, Sims AC, Baric RS, Snijder EJ, van Hemert MJ (2010) Zn2+ Inhibits Coronavirus and Arterivirus RNA Polymerase Activity In Vitro and Zinc Ionophores Block the Replication of These Viruses in Cell Culture. PLoS Pathog 6(11): e1001176. https://doi.org/10.1371/journal.ppat.1001176
2. Xue J, Moyer A, Peng B, Wu J, Hannafon BN, Ding WQ. Chloroquine is a zinc ionophore. PLoS One. 2014;9(10):e109180. Published 2014 Oct 1. doi:10.1371/journal.pone.0109180.
https://pubs.acs.org/doi/10.1021/jf5014633
3. Zakay-Rones, Z., Thom, E., Wollan, T., & Wadstein, J. (2004). Randomized Study of the Efficacy and Safety of Oral Elderberry Extract in the Treatment of Influenza A and B Virus Infections. Journal of International Medical Research, 132–140. https://doi.org/10.1177/147323000403200205
4. J. Hawkins, C. Baker, L. Cherry, E. Dunne. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: a meta-analysis of randomized, controlled clinical trials. Complement Ther Med, 42 (2019 February), pp. 361-365
5. Krawitz, C., Mraheil, M.A., Stein, M. et al. Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses. BMC Complement Altern Med 11, 16 (2011).
https://doi.org/10.1186/1472-6882-11-16
6. Professor Zichria Zakay-Rones, Noemi Varsano, Moshe Zlotnik, Orly Manor, Liora Regev, Miriam Schlesinger, and Madeleine Mumcuoglu. The Journal of Alternative and Complementary Medicine.Dec 1995.361-369.
http://doi.org/10.1089/acm.1995.1.361
7. Husam Dabbagh-Bazarbachi, Gael Clergeaud, Isabel M. Quesada, Mayreli Ortiz, Ciara K. O’Sullivan, and Juan B. Fernández-Larrea. Zinc Ionophore Activity of Quercetin and Epigallocatechin-gallate: From Hepa 1-6 Cells to a Liposome Model. Journal of Agricultural and Food Chemistry 2014 62 (32), 8085-8093 DOI: 10.1021/jf5014633 https://dx.plos.org/10.1371/journal.ppat.1001176
8. 27 Barak V, Halperin T, Kalickman I. The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines: I. Inflammatory cytokines. Eur Cytokine Netw. 2001; 12 290-296
My bad
Correction:
Also quercetin exhibits immunomodulatory effects by increasing cytokine production ….
8. 27 Barak V, Halperin T, Kalickman I. The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines: I. Inflammatory cytokines. Eur Cytokine Netw. 2001; 12 290-296
Should read
In addition quercetin can inhibit viral replication at different stages of the viral lifecycle (8,9)
And has immunomodulatory effects that it exerts through a number of different mechanisms (10)
8. Liu, Z., Zhao, J., Li, W. et al. Computational screen and experimental validation of anti-influenza effects of quercetin and chlorogenic acid from traditional Chinese medicine. Sci Rep 6, 19095 (2016). https://doi.org/10.1038/srep19095
9. Wu, W.; Li, R.; Li, X.; He, J.; Jiang, S.; Liu, S.; Yang, J. Quercetin as an Antiviral Agent Inhibits Influenza A Virus (IAV) Entry. Viruses 2016, 8, 6.
https://www.mdpi.com/1999-4915/8/1/6
10. Li, Y.; Yao, J.; Han, C.; Yang, J.; Chaudhry, M.T.; Wang, S.; Liu, H.; Yin, Y. Quercetin, Inflammation and Immunity. Nutrients 2016, 8, 167.
https://www.mdpi.com/2072-6643/8/3/167
Again thank you all for the great work you are doing.
Truly a pleasure to listen to your podcasts, and the blog posts.