key: cord-0300388-9q4kyntj
authors: Nicolussi, S.; Ardjomand-Woelkart, K.; Stange, R.; Gancitano, G.; Klein, P.; Ogal, M.
title: Echinacea as a Potential Force against Coronavirus Infections? A Mini-Review of Randomized Controlled Trials in Adults and Children
date: 2021-12-24
journal: nan
DOI: 10.1101/2021.12.23.21267893
sha: 443f7b74026c81fd5002641e5176ed66ee40e009
doc_id: 300388
cord_uid: 9q4kyntj

Echinacea purpurea was shown to broadly inhibit coronaviruses and SARS-CoV-2 in vitro. This review discusses the available clinical evidence from randomized, blinded and controlled human studies. Two RCTs with results on enveloped viruses, respectively coronavirus infections during prevention treatment were detected. Incidence and/or viral loads were measured by RT-PCR and symptom severity was recorded. Jawad et al. (2012) collected nasopharyngeal swabs from adults (N=755) over 4 months of continuous prevention. Overall, 24 and 47 enveloped virus infections occurred, including 21 and 33 coronavirus detections [229E; HKU1; OC43] with Echinaforce extract [2400mg daily] and placebo, respectively (p=0.0114). Ogal et al. (2021) administered the same extract [1200mg] or control for 4 months to children (4-12 years) (N=203). Echinacea reduced the incidence of enveloped virus infections from 47 to 29 (p=0.0038) whereas 11 and 13 coronavirus detections [229E, OC43, NL63] were counted (p>0.05). Respiratory symptoms during coronavirus infections were significantly lower with area-under-curve AUC=75.8 (+/-50.24) versus 27.1 (+/-21.27) score points (p=0.0036). Importantly, viral loads in nasal secretions were significantly reduced by 98.5%, with Ct-values 31.1 [95% CI 26.3; 35.9] versus 25.0 [95% CI 20.5; 29.5] (p = 0.0479). Results from clinical studies confirm the antiviral activity found for Echinacea in vitro, embracing enveloped respiratory pathogens and therefore coronaviruses as well. Substantiating results from a new completed study seems to extrapolate these effects to the prevention of SARS-CoV-2 infection. As hypothesized, the testified broad antiviral activity of Echinacea extract appears to be inclusive for SARS-CoV-2.

Echinacea purpurea was shown to broadly inhibit coronaviruses and SARS-CoV-2 in vitro. 18 This review discusses the available clinical evidence from randomized, blinded and controlled hu- 19 man studies. Two RCTs with results on enveloped viruses, respectively coronavirus infections dur-20 ing prevention treatment were detected. Incidence and/or viral loads were measured by RT-PCR 21 28 infections were significantly lower with area-under-curve AUC=75.8 (+/-50.24) versus 27.1 (+/-21.27) 29 score points (p=0.0036). Importantly, viral loads in nasal secretions were significantly reduced by 30 98.5%, with Ct-values 31.1 [95% CI 26.3; 35.9] versus 25.0 [95% CI 20.5; 29 .5] (p = 0.0479). Results 31 from clinical studies confirm the antiviral activity found for Echinacea in vitro, embracing enveloped 32 respiratory pathogens and therefore coronaviruses as well. Substantiating results from a new com-(H1N1), Asia (H2N2) or Hong Kong (H3N2) flu epidemic as well as the more recent bird 46 flu caused by avian H5N1 virus [1] . 47 The 21st century has seen another zoonotic thread, coronaviruses, with successfully con-48 tained outbreaks of SARS-CoV in 2002/2003 or Middle East Respiratory Syndrome CoV) occurring from 2012 to 2015 [2] . Most coronaviruses could be traced back to be of 50 animal origin whereas camels, bats or civet cats are likely natural hosts or vectors [3, 4] . 51 Evidence exists that even the Russian flu was not caused by influenza but by coronavirus 52 strain OC43, due to its highly similar symptomatology to current Covid-19 [5] . Notably, 53 most endemic coronaviruses we know today, originally spilled over from other species as 54 reviewed elsewhere [6] . Due to their high pathogenicity and rather short incubation pe-55 riod, previous coronavirus outbreaks were relatively easy to curb and thus limited to re-56 stricted areas. In contrast, SARS-CoV-2 is much trickier to contain due to its ability to dis-57 seminate through "silent transmitters" during the extended incubation period of up to 14 58 days [7] . Since the newly emerging SARS-CoV-2 was classified as a high-risk pathogen on 59 February 29th 2020 reaching pandemic status in March 11th 2020 the world's endeavors 60 strive to control the dissemination of the virus [8] . 61 Vaccines are a highly efficient means for disease prevention in general and their develop-62 ment nowadays has tremendously been shortened. Nevertheless, from first occurrence 63 (patient zero), virus isolation and determination to large-scale production, distribution of 64 vaccines and final attainment of herd immunity valuable time passes. As the pandemic 65 lingers on, new SARS-CoV-2 variants emerge through inaccurate genetic replication with 66 altered biological behavior and fitness. Several of those variants-of-concern (VOC's) have 67 meanwhile been discovered which display in comparison to the original WUHAN strain 68 more severe pathogenicity and immune evasion potential (e.g. delta variant B.1.671.2 or 69 Omicron B.1.1.529) [9] [10] [11] [12] . 70 Because the preventive potential of vaccination is never complete and depending on cir-71 culating variants, the time point of immunization or an individual's immune status, the 72 demand for novel antivirals for containment of coronavirus infections remains high [13] . 73 Some preparations and practices claim to bolster the immune defense to keep at bay and 74 overcome any potential viral infection. Despite lacking proof of effectiveness for the par-75 ticular pathogen these preparations are intensely consumed. 76 In 2020 scientists have speculated whether usage of minerals, vitamins or herbal prepara-77 tions would be of any help for preventing or treating Covid-19 illness, but recommenda-78 tions mostly relied on theoretical considerations, epidemiological observations, in vitro 79 experiments rather than appropriately controlled intervention trials and therefore re-80 mained speculative [14] [15] [16] [17] . Echinacea, known as the immune herb was highly demanded 81 during the current pandemic and sales steeply increased from 2019 to 2020 by 36.8% in the 82 US [18] . In 2020, Signer et al. published in vitro data revealing a broad virucidal activity 83 for Echinacea purpurea (hydroethanolic extract (65% v/v) of freshly harvested Echinacea pur-84 purea herb and roots manufactured in GMP quality) against all kinds of coronaviruses 85 ranging from the typical common cold CoV-229E to highly pathogenic SARS-CoV-2 vi-86 . CC-BY-ND 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint . Clinical relevance of findings however remained uncertain, because direct con-87 tact of pathogen with the extract was prerequisite for full activity, which was thought to 88 be the case upon sucking tablets/gargling tincture in the pharynx. 89 Besides being antiviral, Echinacea influences the immune system in a manner best de-90 scribed as adaptive immune-modulation, rather than pure immune stimulation. Echinacea 91 significantly reduced the inflammatory cytokines TNF-alpha and IL-1-beta by up to 24% 92 compared to baseline and increased the anti-inflammatory cytokine IL-10. In addition, 93 there was an increase of up to 50% IFN-γ [20, 21] . Further immunomodulatory mechanisms 94 of Echinacea were shown to involve potent activation of the endocannabinoid system (ECS) 95 by specific alkylamides via the CB2 receptor [22, 23] . Several of these bioactive N-alkyla-96 mide principles are structurally similar to endocannabinoids (e.g. anandamide) which in-97 fluence the cytokine milieu in human whole blood at low nanomolar concentrations [24] . 98

During COVID-19 progression, activation of the endocannabinoid system (ECS) could be 99 an additional approach against systemic inflammation and the cytokine storm [25] . Echina-100 cea could therefore reduce inflammatory processes through synergistic immunopharma-101 cological targeting of CB-receptors, mild inhibition of the fatty acid amide hydrolase 102 (FAAH) or endocannabinoid transport [26, 27] . In addition to immunoinflammatory 103 changes, during viral infections, macrophages and neutrophils can produce numerous 104 ROS including hydrogen peroxide (H2O2), superoxide (O2•-) and hydroxyl (OH•) radi-105 cals, which further activate several signaling pathways and institute inflammation and cell 106 death in multiple organs, including the lungs [28] . 107 Preclinical studies thus attribute pharmacological actions to Echinacea, which could be ben-108 eficial for the prevention and treatment of viral diseases. fections AND terms related to study design (RCTs). A detailed search strategy is shown in 117 Appendix 1. 118 Obtained articles were further selected for clinical trials studying respiratory tract infec-119 tions in humans and detection of respiratory viruses independently by SN and GG. In case 120 of discrepancy regarding eligibility of articles, consensus was sought between all authors 121 prior to inclusion or rejection. The research outcome was to be presented in a flow chart as 122 requested by PRISMA [29] . In case of inconsistencies or missing information, the corre-123 sponding authors of the published article was contacted for further information. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. ; https://doi.org/10.1101/2021.12.23.21267893 doi: medRxiv preprint Data extraction was undertaken using a pre-defined form retrieving the following infor-128 mation: primary author's name, publication date, country, study design, sample size, re-129 searched plant species and preparation, duration of treatment (prevention vs acute treat-130 ment), dosage, incidence of coronavirus virus infections and virus concentration (Ct-val-131 ues), information regarding symptomatic development (e.g., total symptom score, episode 132 duration, area-under-curve or similar). The methodological quality of included studies 133 was assessed using the criteria as proposed by Jadad [30] . Results are provided for safety 134 (SAF), intention-to-treat (ITT) or as indicated for the per protocol (PP) populations. 135 

A total of N=1687 articles were identified through database searching including PubMed 137 and EMBASE using a combination of keywords, which includes Medical Subject Headings 138 (MeSH)/Emtree terms (Embase Subject Headings). For further details see Appendix 1. 139 N=988 articles were excluded at the initial screening due to duplicated and irrelevant arti-140 cles. Sixty potentially relevant articles were selected for the full text assessment, of which 141 58 were further excluded due to studies that were not reporting respiratory tract -or coro-142 navirus infections, Echinacea species, non-RCT and human studies (n= 57) or combination 143 of Zingiber officinale and Echinacea (N=1), which is detailed in PRISMA flow chart ( Figure 144 1). Finally, two studies selected for the systematic review, which met the eligibility criteria 145 of the current study (Table 1) . 146 Due to the low number of referenced studies we abstained from carrying out a quantitative 147 meta-analysis. Instead, we decided to qualitatively discuss the observed findings from the 148 two contributions, which are detailed in the following. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint Overall, N=755 subjects were randomized to E. purpurea or placebo and N=717 subjects 173 were eligible for analysis as per safety collective (SAF). Preventive benefits were reported 174 on the level of total cold episodes, cumulative cold days and recurrent episodes. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. ; https://doi.org/10.1101/2021.12.23.21267893 doi: medRxiv preprint 6 of 16 and NL63). The methodological quality according to Jadad was with 4 points again high 210 [30] . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. ; https://doi.org/10.1101/2021.12.23.21267893 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint 

Country Jadad Score is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. ; https://doi.org/10.1101/2021.12.23.21267893 doi: medRxiv preprint harvested Echinacea purpurea and an obvious specificity towards enveloped pathogens 263 could be verified [39] . The extract appears to block interaction of viral docking receptors 264 (e.g. hemagglutinin on influenza) with structures on the target cell and is thus expected to 265 prevent infection, although the detailed mechanism of action still has to be elucidated 266 [37] . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint scribed blinding, randomization, were appropriately controlled and referred to data set 278 from almost 1000 patients treated over a period of 4 months with either tincture or tablets 279 from the same 65% (v/v) ethanolic extract from Echinacea purpurea. Due to the low number 280 of included studies, we abstained from pooling results, but to qualitatively describe out-281 comes from the studies. 282 Preventive antiviral effects for Echinacea for coronavirus infections were seen in both stud-283 ies by varying parameters. 4-months supplementation with Echinacea in adults and chil-284 dren reduced the incidence of coronaviruses as part of its effect on enveloped virus infec-285 tions and virus concentration in nasopharynx in the latter, respectively. Jawad did not 286 measure virus concentrations (Ct-value), and this information was therefore lacking. Ogal 287 employed a newer, more sensitive method for detection that was able to detect as few as 288 100 viral genome copies. We presume that Echinacea's antiviral effects generally reduced 289 the amount of viruses, that in Jawad study suppressed below detection limits resulting in 290 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. significantly reduced fever days (1 day vs. 11 days, Chi square test, p=0.003) [40] . 340 Findings still await publication in peer-reviewed journal and need to be treated with ap-341 propriate caution. They were nevertheless mentioned in the current review for the sake of 342 completeness and because they seem to confirm applicability of antiviral benefits of 343 Echinacea to a broad range of coronaviruses, including SARS-CoV-2. 344 Despite limitations associated with this review (e.g. low number of studies) we believe that 345 our findings are highly relevant as they provide a rather consistent picture on antiviral and 346 preventive benefits of Echinacea in coronavirus infections overall. Also, they provide im-347 portant implications for the preventive use of Echinacea during Covid-19 epidemic. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. ; https://doi.org/10.1101/2021.12.23.21267893 doi: medRxiv preprint extract may be key to inactivate respiratory viruses at the main entry site prior to infection 359 [19] . Further could any viral attenuation in this region prevent further dissemination of 360 nasal infections to the lungs, as seen with severe progressions of Covid-19. Indeed, a recent 361 meta-analysis found a significant prevention of pneumonia secondary to viral respiratory 362 tract infections upon 2 to 4 months Echinacea prevention [45]. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted December 24, 2021. ; https://doi.org/10.1101/2021.12.23.21267893 doi: medRxiv preprint

Thrusting Coronaviruses into the Spotlight. Viruses

History and recent advances in coronavirus discovery

S223-7, discussion S226

SARS-CoV-2 jumping the species barrier: Zoonotic lessons from SARS, MERS and recent advances to 401 combat this pandemic virus

Delta variants of SARS-CoV-2 cause significantly increased vaccine breakthrough 404 COVID-19 cases in

Resurgence of SARS-CoV-2 in India: Potential role of the B.1.617.2 (Delta) 407 variant and delayed interventions

SARS-CoV-2 Variants and Their Relevant Mutational Profiles: Update Summer 2021

Heavily mutated Omicron variant puts scientists on alert

The search for antivirals for covid-19

Role of vitamin D in preventing of COVID-19 infection, progression and severity

Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19)

Mini-Review on the Roles of Vitamin C, Vitamin D, and Selenium in the Immune System 420 against COVID-19

The effect of Echinacea spp. on the prevention or treatment of COVID-19 and other respiratory tract 423 infections in humans: A rapid review

US Herbal Supplement Sales Increase by Record-breaking 17

Effects of Echinaforce® treatment on ex vivo-stimulated blood 431 cells

Moench treatment of monocytes promotes tonic interferon signaling, increased innate immunity gene 434 expression and DNA repeat hypermethylated silencing of endogenous retroviral sequences

Echinacea alkylamides modulate TNF-alpha gene expression via 437 cannabinoid receptor CB2 and multiple signal transduction pathways

The endocannabinoid system as a target 440 for alkamides from Echinacea angustifolia roots

Alkylamides 442 from Echinacea are a new class of cannabinomimetics. Cannabinoid type 2 receptor-dependent and -443 independent immunomodulatory effects

Use of Cannabinoids to Treat Acute Respiratory Distress Syndrome 445 and Cytokine Storm Associated with Coronavirus Disease-2019

Synergistic 448 immunomopharmacological effects of N-alkylamides in Echinacea purpurea herbal extracts

27. Nicolussi, S.; Gertsch

Identification of oxidative stress and Toll-like receptor 4 signaling as a key 453 pathway of acute lung injury

Preferred reporting items for systematic reviews and meta-455 analyses: the PRISMA statement

Assessing the 457 quality of reports of randomized clinical trials: is blinding necessary?

V Transmission of the common cold to volunteers under 463 controlled conditions. I. The common cold as a clinical entity

Efficacy and safety of Echinaforce® in respiratory tract infections

Echinacea reduces antibiotic usage in children through respiratory 468 tract infection prevention: a randomized, blinded, controlled clinical trial

Development of a symptom score for clinical 471 studies to identify children with a documented viral upper respiratory tract infection

Echinacea as an antiinflammatory agent: the influence of physiologically 474 relevant parameters

Anti-viral properties and mode of action of standardized 476

Echinacea purpurea extract against highly pathogenic avian influenza virus (H5N1, H7N7) and swine-origin 477

Induction of multiple pro-inflammatory cytokines by 481 respiratory viruses and reversal by standardized Echinacea, a potent antiviral herbal extract

Echinacea purpurea for the Long-term Prevention of Viral Respiratory Tract Infections during COVID-485 19 Pandemic: A Randomized, Open, Controlled, Exploratory Clinical Study. medRxiv 2021

Higher Viral Load Drives Infrequent Severe Acute Respiratory Syndrome Coronavirus

Transmission Between Asymptomatic Residence Hall Roommates

We would like to thank Roland Schoop from the A.Vogel AG company for 377 providing us with study details on coronavirus infections. 

The search strategy and results are detailed in Appendix 1. 381