While New Zealand has been one of the most successful countries in the world at not letting Covid-19 (SARS-CoV-2) become a rampant infection throughout its communities, the global impact of this pandemic remains extremely high. Given how difficult an elimination strategy has been to execute, and the economic consequences of lockdowns, many countries are now in the process of developing and implementing policies that are based upon learning to live with rather than eliminate it.
The last 18 months have seen a whirlwind of change as this clever virus has caused so many deaths and disrupted so many lives. Over the next year or two we will undoubtedly continue to see further new developments, including the emergence of new variants and increased rates of vaccination, but also further increases in our understanding about how to best deal with the virus in different scenarios.
Recent experiences of our cousins over the ditch in Australia, highlight just how easy it is to tilt from living life largely as we used to, to being back in lockdown, as the more infectious delta variant runs through communities. New South Wales has just recorded 163 cases in the last 24 hours, its highest number of new cases since the latest outbreak began. Other nearby countries such as Fiji, are presently faring much worse, with 918 new cases and 15 more deaths confirmed in the 24 hours to 22nd July.
Apart from being more infectious, studies suggest the delta variant can also produce a much higher viral load within the respiratory system than the original strain of the virus. This combination of a higher viral load and more efficient transmission, makes this variant particularly worrisome.
While vaccination rates are increasing, supply shortfalls and differing levels of prophylactic efficacy, are concerns. Additionally, the duration of immune memory and thus protective immunity after contracting a Covid-19 infection, or after vaccination, are still unknowns that will take years to gather reliable data on(1). All of this and more, highlights just how challenging the battle against this virus is, and that its impact on our lives will continue for a long time yet.
New Zealand modelling has estimated that to ensure herd immunity, an overall vaccination rate of around 83 percent using the Pfizer vaccine will be required. With the more contagious delta variant however, a vaccination rate of 97%, is likely to be needed(2).
Discussing the pros and cons of vaccination is not the purpose of this article. But what now seems clear, is that achieving these levels of vaccination in our population, is very unlikely to happen. While most New Zealanders will probably opt for vaccination particularly as the global situation remains dire, I cant see more than 70% of the population being vaccinated anytime soon. The conclusion now being reached by epidemiologists and microbiologists is that in addition to relying heavily on vaccination, we’ll probably need to maintain and add a mix of other measures in order to achieve an acceptable level of population immunity. Ongoing border restrictions, mask wearing, social distancing and the need for differing levels of lockdown in the coming months or more, seems unavoidable. In addition to such measures, a focus on individual immunity and treatment interventions should an infection arise, is also important.
Plants have enormous potential to help optimise immunity in humans, and a healthy vegetable and fruit rich diet, is linked with favourable influences on the gut microbiome and immune function. Their complex phytochemistry including diverse polyphenolic molecules and fibre, and vitamins such as vitamin C, contribute to the healthy functioning of these bodily defence systems.
The use of herbal medicines or supplementation of the diet with immune enhancing herbs and spices for at least 14 days during periods of community outbreaks, is a recommendable component of a Covid-19 management strategy. Culinary herbs and spices such as ginger, blackseed and holy basil show potential as antiviral agents and immunity enhancers against viral infections, while others such as horseradish, cinnamon thyme, oregano and garlic, may be useful to help prevent or treat secondary bacterial infections that can contribute to patients becoming seriously unwell(3).
Variations in death rates from Covid-19 in different countries, may in fact partly relate to differences in diet. Associations have been suggested between several countries with low Covid-19 death rates, and traditional diets which incorporate large quantities of certain spices, or fermented vegetables (such as cassava in Africa, cabbage and other cruciferous vegetables in Germany and Korea)(4, 5).
Echinacea (Purple coneflower) is one of the most promising immune enhancers from both a traditional as well as evidence-based perspective, and has pronounced anti-inflammatory and immunomodulatory effects. Its immunomodulatory mode of action, whereby it enhances the immune system when taken in the absence of infection, but may reduce excessive and possibly damaging inflammation (the ‘cytokine storm’) during a viral infection, is of particular interest. These properties suggest both a useful prophylactic effect of Echinacea against unwanted viruses, but also a potential usefulness during upper respiratory tract viral infections(6).
While a Cochrane review found Vitamin C supplementation of at least 200mg per day to be associated with a 7.7% reduction in the duration of colds in adults(7), a recent clinical trial which investigated the effects of 8 grams a day of vitamin C or its combination with zinc on recovery from Covid-19 infection, was stopped early due to disappointing results(8). The methodology of this trial and rationale for its early termination, has however been challenged(9).
Vitamin D deficiency has been revealed as a significant risk factor for acute respiratory distress syndrome, heart failure and sepsis, as well as in critically ill Covid-19 patients(10, 11). Apart from addressing any deficiency as a prophylactic measure, supplementation and restoration to normal range of vitamin D in patients with Covid-19, has been reported to reduce inflammation and improve their immunologic state during antiviral drug treatment(12, 13).
Addressing weight loss when obesity is an issue, is also advisable. A retrospective study in China reported that 88% of non-survivors of Covid-19 with cardiovascular disease had a body mass index (BMI) over 25, as opposed to 18% in the survivor group(14). Similarly a study involving 124 hospitalised Covid-19 patients in France observed that patients with a BMI over 35 were 7 times more at risk of requiring invasive mechanical ventilation during their ICU stay than patients with a BMI less than 25(15)..
Some recent findings:
Despite all the grim news of late, there’s actually been a fair amount of encouraging research undertaken over the past year into plant-derived medicines and their influences on this cunning virus. Much of this has taken place in countries where the pandemic’s impact has been severe, and in others where traditional and plant-based medicines have for many years now been a focus of government health policies and research funding.
Herbal medicines can work well when combined appropriately with drug and other conventional therapies, and this is also the case with Covid-19 patients. In China, incorporation of traditional Chinese herbal treatments into the management of patients with Covid-19 has achieved additional benefits to those seen through drug-based treatment alone(16-20). Similar experiences have been reported through the use of traditional herbal medicines in India and other countries(21-23).
Another example of this is propolis, the resinous substance that bees produce from plant pollens, to help protect their hives. Propolis is full of powerful phytochemicals including many with antiviral properties, and results from a clinical trial involving patients hospitalized with Covid-19 in Brazil, are encouraging. Propolis administration alongside the various conventional drugs and treatments given to seriously ill Covid-19 patients, lead to a much faster recovery time and halving of the median duration of hospital stay, from 12 to 6 days(24, 25). The extent of kidney damage was also reduced in patients given propolis.
Separate clinical trials are also planned or underway in Iran into the use of ginger(26) or pomegranate juice(27) alongside standard hospital treatment for Covid-19, which will measure both inflammatory markers and clinical outcomes. In Saudi Arabia a trial is underway into adjunctive use of the popular middle eastern spice blackseed (Nigella sativa, or black cumin)(28). Several Nigella components have shown promise in in vitro studies as anti-viral agents(29-32).
Extracts of the medicinal fungus Ganoderma lucidum (Reishi), and the wild and culinary herbs Perilla frutescens (Perilla) and Mentha haplocalyx (Mint), have all recently been found to reduce the viral load in animal studies(33). Reishi exhibits antiviral activities also against herpes simplex, dengue fever, hepatitis B, and HIV (34). A combination of Reishi with another medicinal mushroom Lions Mane (Hericium erinaceus), significantly reduced bacteraemia and increased the survival in mice with pneumococcal sepsis(35). As with many other medicinal herbs, these mushroom extracts may exhibit preventive or therapeutic effects against severe bronchial infections and lung inflammation, that feature in severe Covid-19 infections.
In India, the highly regarded immunomodulatory and anti-inflammatory medicinal herb Andrographis paniculata, is being further researched by local scientists. Synergy has been shown between andrographolide and its other phytochemicals, in effects on upper respiratory tract infections and the ability to significantly decrease the production of pro-inflammatory cytokines in viral infections(36). Andrographolide seems to bind with crucial proteins to block the TNF-induced NFkB1 signaling pathway which contributes to the cytokine storm in Covid-19 patients(37). It also seems to inhibit the main protease and other key targets of the virus responsible for replication, transcription and host cell recognition(38, 39).
Sumac is the name given to many different species of Rhus, medicinal flowering plants that are endemic in temperate and tropical regions, including China (Rhus chinensis), the Middle east, and North America. Traditional uses in multiple countries include for antiviral, antimicrobial, antibacterial, antioxidant, and wound-healing properties. Molecular docking and drug-likeness studies have revealed potential protease inhibitory properties for various polyphenolic constituents of Rhus chinensis(40). Other Sumac extracts also exhibit organ-protective properties of relevance to Covid-19 pathology, and may also be useful during infections(41).
In South America, the highly regarded medicinal tree Cats Claw (Uncaria tomentosa), has also been reported to contain compounds which inhibit the virus’s main protease(42, 43). A hydroethanolic extract of its stem bark, also inhibited the virus(44).
Desperate times lead to desperate measures however, and in some instances there have been exaggerated claims of efficacy with little evidence basis, for the use of particular plant medicines in treating symptoms of Covid-19 infection.
What is evident from the many studies either completed or underway in numerous countries of the world, is that planning and funding for research into specific locally available plants and dietary interventions, seems to be paying dividends. In most cases, targeted investigations into relevant traditional and historical uses of some highly regarded local species, including the application of molecular docking and other modern research technologies, combined with the incorporation of learnings to date about how this virus replicates and causes harm, is proving to be a worthwhile approach.
- Sette A, Crotty S. Adaptive immunity to SARS-CoV-2 and COVID-19. Cell. 2021;184(4):861-880. doi:10.1016/j.cell.2021.01.007.
- A COVID-19 vaccination model for Aotearoa New Zealand (tepunahamatatini.ac.nz)
- Rasmussen PL, Culinary herbs and spices to know about, in infectious times. www.herbblurb.com Mar 20, 2020.
- Bousquet J, Czarlewski W, Zuberbier T, Mullol J, Blain H, Cristol JP, De La Torre R, Le Moing V, Pizarro Lozano N, Bedbrook A, Agache I, Akdis CA, Canonica GW, Cruz AA, Fiocchi A, Fonseca JA, Fonseca S, Gemicioğlu B, Haahtela T, Iaccarino G, Ivancevich JC, Jutel M, Klimek L, Kuna P, Larenas-Linnemann DE, Melén E, Okamoto Y, Papadopoulos NG, Pfaar O, Reynes J, Rolland Y, Rouadi PW, Samolinski B, Sheikh A, Toppila-Salmi S, Valiulis A, Choi HJ, Kim HJ, Anto JM. Spices to Control COVID-19 Symptoms: Yes, but Not Only…. Int Arch Allergy Immunol. 2021;182(6):489-495. doi: 10.1159/000513538. Epub 2020 Dec 22. PMID: 33352565; PMCID: PMC7900475.
- Bousquet J, Anto JM, Czarlewski W, Haahtela T, Fonseca SC, Iaccarino G, Blain H, Vidal A, Sheikh A, Akdis CA, Zuberbier T; ARIA group. Cabbage and fermented vegetables: From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19. Allergy. 2021 Mar;76(3):735-750. doi: 10.1111/all.14549. Epub 2020 Sep 15. PMID: 32762135; PMCID: PMC7436771.
- Rasmussen PL, Echinacea in the time of a pandemic. www.herbblurb.com Oct 20, 2020.
- Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013 Jan 31;2013(1):CD000980. doi: 10.1002/14651858.CD000980.pub4. PMID: 23440782; PMCID: PMC8078152.
- Thomas S, Patel D, Bittel B, Wolski K, Wang Q, Kumar A, Il’Giovine ZJ, Mehra R, McWilliams C, Nissen SE, Desai MY. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2021 Feb 1;4(2):e210369. doi: 10.1001/jamanetworkopen.2021.0369. PMID: 33576820; PMCID: PMC7881357.
- Hemilä H, Carr A. Comment on “Therapeutic target and molecular mechanism of vitamin C-treated pneumonia: a systematic study of network pharmacology” by R. Li, C. Guo, Y. Li, X. Liang, L. Yang and W. Huang, Food Funct., 2020, 11, 4765. Food Funct. 2021 Feb 15;12(3):1371-1372. doi: 10.1039/d0fo02189j. PMID: 33449981.
- Grant WB, Lahore H, McDonnell SL, Baggerly CA, French CB, Aliano JL, Bhattoa HP. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients. 2020 Apr 2;12(4):988. doi: 10.3390/nu12040988. PMID: 32252338; PMCID: PMC7231123.
- Tian Y, Rong L. Covid-19 and vitamin D – authors reply. Aliment Pharmacol Ther 51(10):995-996.
- Caccialanza R et al, Nutrition 2020; 110835.
- Annweiler G, Corvaisier M, Gautier J, Dubée V, Legrand E, Sacco G, Annweiler C. Vitamin D Supplementation Associated to Better Survival in Hospitalized Frail Elderly COVID-19 Patients: The GERIA-COVID Quasi-Experimental Study. Nutrients. 2020 Nov 2;12(11):3377. doi: 10.3390/nu12113377. PMID: 33147894; PMCID: PMC7693938.
- Peng YD, Meng K, Guan HQ, Leng L, Zhu RR, Wang BY, He MA, Cheng LX, Huang K, Zeng QT. [Clinical characteristics and outcomes of 112 cardiovascular disease patients infected by 2019-nCoV]. Zhonghua Xin Xue Guan Bing Za Zhi. 2020 Jun 24;48(6):450-455. Chinese. doi: 10.3760/cma.j.cn112148-20200220-00105. PMID: 32120458.
- Simonnet A, Chetboun M, Poissy J, Raverdy V, Noulette J, Duhamel A, Labreuche J, Mathieu D, Pattou F, Jourdain M; LICORN and the Lille COVID-19 and Obesity study group. High Prevalence of Obesity in Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Requiring Invasive Mechanical Ventilation. Obesity (Silver Spring). 2020 Jul;28(7):1195-1199. doi: 10.1002/oby.22831. Epub 2020 Jun 10. Erratum in: Obesity (Silver Spring). 2020 Oct;28(10):1994. PMID: 32271993; PMCID: PMC7262326.
- Deng JG, Hou XT, Zhang TJ, Bai G, Hao EW, Chu JJH, Wattanathorn J, Sirisa-Ard P, Soo Ee C, Low J, Liu CX. Carry forward advantages of traditional medicines in prevention and control of outbreak of COVID-19 pandemic. Chin Herb Med. 2020 Jul;12(3):207-213. doi: 10.1016/j.chmed.2020.05.003. Epub 2020 Jun 2. PMID: 32834811; PMCID: PMC7266592.
- Guo DA. Traditional Chinese medicine played a crucial role in battling COVID-19. Chin Herb Med. 2020 Jul;12(3):205-206. doi: 10.1016/j.chmed.2020.07.001. Epub 2020 Jul 9. PMID: 32834810; PMCID: PMC7343649.
- Wang Y, Li X, Zhang JH, Xue R, Qian JY, Zhang XH, Zhang H, Liu QQ, Fan XH, Cheng YY, Zhang BL. [Mechanism of Xuanfei Baidu Tang in treatment of COVID-19 based on network pharmacology]. Zhongguo Zhong Yao Za Zhi. 2020 May;45(10):2249-2256. Chinese. doi: 10.19540/j.cnki.cjcmm.20200325.401. PMID: 32495577.
- Hu K, Guan WJ, Bi Y, Zhang W, Li L, Zhang B, Liu Q, Song Y, Li X, Duan Z, Zheng Q, Yang Z, Liang J, Han M, Ruan L, Wu C, Zhang Y, Jia ZH, Zhong NS. Efficacy and safety of Lianhuaqingwen capsules, a repurposed Chinese herb, in patients with coronavirus disease 2019: A multicenter, prospective, randomized controlled trial. Phytomedicine. 2021 May;85:153242. doi: 10.1016/j.phymed.2020.153242. Epub 2020 May 16. PMID: 33867046; PMCID: PMC7229744.
- Zheng S, Baak JP, Li S, Xiao W, Ren H, Yang H, Gan Y, Wen C. Network pharmacology analysis of the therapeutic mechanisms of the traditional Chinese herbal formula Lian Hua Qing Wen in Corona virus disease 2019 (COVID-19), gives fundamental support to the clinical use of LHQW. Phytomedicine. 2020 Dec;79:153336. doi: 10.1016/j.phymed.2020.153336. Epub 2020 Sep 6. PMID: 32949888; PMCID: PMC7474845.
- Charan J, Kaur R, Bhardwaj P, Kanchan T, Mitra P, Yadav D, Sharma P, Misra S. Snapshot of COVID-19 Related Clinical Trials in India. Indian J Clin Biochem. 2020 Aug 10;35(4):1-5. doi: 10.1007/s12291-020-00918-1. Epub ahead of print. PMID: 32837035; PMCID: PMC7416656.
- Borse S, Joshi M, Saggam A, Bhat V, Walia S, Marathe A, Sagar S, Chavan-Gautam P, Girme A, Hingorani L, Tillu G. Ayurveda botanicals in COVID-19 management: An in silico multi-target approach. PLoS One. 2021 Jun 11;16(6):e0248479. doi: 10.1371/journal.pone.0248479. PMID: 34115763; PMCID: PMC8195371.
- Aldwihi LA, Khan SI, Alamri FF, AlRuthia Y, Alqahtani F, Fantoukh OI, Assiri A, Almohammed OA. Patients’ Behavior Regarding Dietary or Herbal Supplements before and during COVID-19 in Saudi Arabia. Int J Environ Res Public Health. 2021 May 11;18(10):5086. doi: 10.3390/ijerph18105086. PMID: 34064950; PMCID: PMC8151200.
- Silveira MAD, De Jong D, Berretta AA, et al. Efficacy of Brazilian green propolis (EPP-AF®) as an adjunct treatment for hospitalized COVID-19 patients: A randomized, controlled clinical trial. Biomed Pharmacother. 2021;138:111526. doi:10.1016/j.biopha.2021.111526.
- Rasmussen PL, Propolis: amazing stuff made by bees from nature. www.herbblurb.com Apr 9, 2021.
- Safa O, Hassaniazad M, Farashahinejad M, Davoodian P, Dadvand H, Hassanipour S, Fathalipour M. Effects of Ginger on clinical manifestations and paraclinical features of patients with Severe Acute Respiratory Syndrome due to COVID-19: A structured summary of a study protocol for a randomized controlled trial. Trials. 2020 Oct 9;21(1):841. doi: 10.1186/s13063-020-04765-6. PMID: 33036662; PMCID: PMC7545374.
- Yousefi M, Sadriirani M, PourMahmoudi A, Mahmoodi S, Samimi B, Hosseinikia M, Saeedinezhad Z, Panahande SB. Effects of pomegranate juice (Punica Granatum) on inflammatory biomarkers and complete blood count in patients with COVID-19: a structured summary of a study protocol for a randomized clinical trial. Trials. 2021 Apr 2;22(1):246. doi: 10.1186/s13063-021-05194-9. PMID: 33810808; PMCID: PMC8017515.
- Koshak AE, Koshak EA, Mobeireek AF, Badawi MA, Wali SO, Malibary HM, Atwah AF, Alhamdan MM, Almalki RA, Madani TA. Nigella sativa supplementation to treat symptomatic mild COVID-19: A structured summary of a protocol for a randomised, controlled, clinical trial. Trials. 2020 Aug 8;21(1):703. doi: 10.1186/s13063-020-04647-x. PMID: 32771034; PMCID: PMC7414256.
- Koshak DAE, Koshak PEA. Nigella sativa L as a potential phytotherapy for coronavirus disease 2019: A mini review of in silico studies. Curr Ther Res Clin Exp. 2020;93:100602. doi: 10.1016/j.curtheres.2020.100602. Epub 2020 Aug 25. PMID: 32863400; PMCID: PMC744515.
- Siddiqui S, Upadhyay S, Ahmad R, Gupta A, Srivastava A, Trivedi A, Husain I, Ahmad B, Ahamed M, Khan MA. Virtual screening of phytoconstituents from miracle herb nigella sativa targeting nucleocapsid protein and papain-like protease of SARS-CoV-2 for COVID-19 treatment. J Biomol Struct Dyn. 2020 Dec 8:1-21. doi: 10.1080/07391102.2020.1852117. Epub ahead of print. PMID: 33289456; PMCID: PMC7738213.
- Maideen NMP. Prophetic Medicine-Nigella Sativa (Black cumin seeds) – Potential herb for COVID-19? J Pharmacopuncture. 2020 Jun 30;23(2):62-70. doi: 10.3831/KPI.2020.23.010. Erratum in: J Pharmacopuncture. 2020 Sep 30;23(3):179. PMID: 32685234; PMCID: PMC7338708.
- Ahmad S, Abbasi HW, Shahid S, Gul S, Abbasi SW. Molecular docking, simulation and MM-PBSA studies of nigella sativa compounds: a computational quest to identify potential natural antiviral for COVID-19 treatment. J Biomol Struct Dyn. 2021 Aug;39(12):4225-4233. doi: 10.1080/07391102.2020.1775129. Epub 2020 Jun 12. PMID: 32462996; PMCID: PMC7298883.
- Jan JT, Cheng TR, Juang YP, Ma HH, Wu YT, Yang WB, Cheng CW, Chen X, Chou TH, Shie JJ, Cheng WC, Chein RJ, Mao SS, Liang PH, Ma C, Hung SC, Wong CH. Identification of existing pharmaceuticals and herbal medicines as inhibitors of SARS-CoV-2 infection. Proc Natl Acad Sci U S A. 2021 Feb 2;118(5):e2021579118. doi: 10.1073/pnas.2021579118. PMID: 33452205; PMCID: PMC7865145.
- Rai MK, Gaikwad S, Nagaonkar D, dos Santos CA. Current Advances in the Antimicrobial Potential of Species of Genus Ganoderma (Higher Basidiomycetes) against Human Pathogenic Microorganisms (Review). Int J Med Mushrooms. 2015;17(10):921-32. doi: 10.1615/intjmedmushrooms.v17.i10.20. PMID: 26756184.
- Hetland G, Johnson E, Bernardshaw SV, Grinde B. Can medicinal mushrooms have prophylactic or therapeutic effect against COVID-19 and its pneumonic superinfection and complicating inflammation? Scand J Immunol. 2021 Jan;93(1):e12937. doi: 10.1111/sji.12937. Epub 2020 Jul 29. PMID: 32657436; PMCID: PMC7404338.
- Banerjee S, Kar A, Mukherjee PK, Haldar PK, Sharma N, Katiyar CK. Immunoprotective potential of Ayurvedic herb Kalmegh (Andrographis paniculata) against respiratory viral infections – LC-MS/MS and network pharmacology analysis. Phytochem Anal. 2021 Jul;32(4):629-639. doi: 10.1002/pca.3011. Epub 2020 Nov 9. PMID: 33167083.
- Rehan M, Ahmed F, Howladar SM, Refai MY, Baeissa HM, Zughaibi TA, Kedwa KM, Jamal MS. A Computational Approach Identified Andrographolide as a Potential Drug for Suppressing COVID-19-Induced Cytokine Storm. Front Immunol. 2021 Jun 24;12:648250. doi: 10.3389/fimmu.2021.648250. PMID: 34248936; PMCID: PMC8264290.
- Murugan NA, Pandian CJ, Jeyakanthan J. Computational investigation on Andrographis paniculata phytochemicals to evaluate their potency against SARS-CoV-2 in comparison to known antiviral compounds in drug trials. J Biomol Struct Dyn. 2021 Aug;39(12):4415-4426. doi: 10.1080/07391102.2020.1777901. Epub 2020 Jun 16. PMID: 32543978.
- Enmozhi SK, Raja K, Sebastine I, Joseph J. Andrographolide as a potential inhibitor of SARS-CoV-2 main protease: an in silico approach. J Biomol Struct Dyn. 2021 Jun;39(9):3092-3098. doi: 10.1080/07391102.2020.1760136. Epub 2020 May 5. PMID: 32329419; PMCID: PMC7212536.
- Sherif YE, Gabr SA, Hosny NM, Alghadir AH, Alansari R. Phytochemicals of Rhus spp. as Potential Inhibitors of the SARS-CoV-2 Main Protease: Molecular Docking and Drug-Likeness Study. Evid Based Complement Alternat Med. 2021;2021:8814890. Published 2021 Feb 27. doi:10.1155/2021/8814890
- Korkmaz H. Could Sumac Be Effective on COVID-19 Treatment? J Med Food. 2021 Jun;24(6):563-568. doi: 10.1089/jmf.2020.0104. Epub 2020 Aug 18. PMID: 32816615.
- Yepes-Pérez AF, Herrera-Calderon O, Sánchez-Aparicio JE, Tiessler-Sala L, Maréchal JD, Cardona-G W. Investigating Potential Inhibitory Effect of Uncaria tomentosa (Cat’s Claw) against the Main Protease 3CLpro of SARS-CoV-2 by Molecular Modeling. Evid Based Complement Alternat Med. 2020 Sep 30;2020:4932572. doi: 10.1155/2020/4932572. PMID: 33029165; PMCID: PMC7532411.
- Yepes-Pérez AF, Herrera-Calderon O, Quintero-Saumeth J. Uncaria tomentosa (cat’s claw): a promising herbal medicine against SARS-CoV-2/ACE-2 junction and SARS-CoV-2 spike protein based on molecular modeling. J Biomol Struct Dyn. 2020 Oct 29:1-17. doi: 10.1080/07391102.2020.1837676. Epub ahead of print. PMID: 33118480; PMCID: PMC7657399.
- Yepes-Perez AF, Herrera-Calderón O, Oliveros CA, Flórez-Álvarez L, Zapata-Cardona MI, Yepes L, Aguilar-Jimenez W, Rugeles MT, Zapata W. The Hydroalcoholic Extract of Uncaria tomentosa (Cat’s Claw) Inhibits the Infection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) In Vitro. Evid Based Complement Alternat Med. 2021 Feb 24;2021:6679761. doi: 10.1155/2021/6679761. PMID: 33680061; PMCID: PMC7929665.