Select Global Immune-Boosting Plants Used in Folklore Medicine

There are numerous foods and herbal plants that boost the immune system. They stimulate the activity of cells responsible for fighting infections. In fact, over centuries, people have relied on herbs and other plants for treating medical conditions and boosting immunity. Considering the worldwide coronavirus pandemic, natural immune boosters are being sought after in the current war against this viral infection. Most likely, immune-boosting plants help human health by tackling viruses, bacteria, and abnormal cells in the form of prevention, to support and strengthen the body's natural immune system. In this chapter, we review several terrestrial species and plants from various sources including China, India, Europe, and Africa, which have long folklore use, and we provide information on the chemistry and biological activity where available. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.

Sambucus ebulus (Elderberry) Fruits Modulate Inflammation and Complement System Activity in Humans.

Sambucus ebulus (SE) fruits are used for immune stimulation and amelioration of gastrointestinal inflammatory conditions. Currently, there is no scientific evidence of their effects on various aspects of the immune response mechanisms in humans. The purpose of this study was to evaluate the immunomodulatory potential of SE fruit infusion intake in healthy humans. Anthocyanin content was determined with UPLC-ESI-MS/MS. Fifty-three volunteers enrolled in a 4-week SE infusion intake intervention. Blood count, serum total protein, Interleukin 1 beta (IL-1ß), Interleukin 6 (IL-6), Tumor Necrosis Factor Alpha (TNFα), High-sensitivity C-reactive protein (hs-CRP), C3, and C4 levels were measured on automatic analyzers, and Interleukin 8 (IL-8) was measured manually with an ELISA kit. Cyanidin-3-O-galactoside (48.15 mg/g DW), followed by cyaniding-3-sambubioside (43.41 ± 1.07 mg/g DW), were the most abundant anthocyanins in SE samples. A significant decrease in total protein (2.82%), IL-6 (20.15%), TNFα (5.38%), IL-8 (5.50%), C3 (4.16%), and C4 (14.29%) was established in the whole group. Total protein, IL-8, TNFα, and C4 decreased in women (3.11%, 4.76%, 5.09%, and 11.11%), and IL-6 decreased (40.61%) in men. Hb (1.20%) and hematocrit (1.55%) levels decreased in the whole group and in the women group (1.61% and 2.20%). SE fruits exert immune-modulatory activity as revealed by decreased pro-inflammatory status and complement activity markers in healthy volunteers after a 4-week intervention.

Elderberry Extracts: Characterization of the Polyphenolic Chemical Composition, Quality Consistency, Safety, Adulteration, and Attenuation of Oxidative Stress- and Inflammation-Induced Health Disorders.

Elderberry is highly reputed for its health-improving effects. Multiple pieces of evidence indicate that the consumption of berries is linked to enhancing human health and preventing or delaying the onset of chronic medical conditions. Compared with other fruit, elderberry is a very rich source of anthocyanins (approximately 80% of the polyphenol content). These polyphenols are the principals that essentially contribute to the high antioxidant and anti-inflammatory capacities and the health benefits of elderberry fruit extract. These health effects include attenuation of cardiovascular, neurodegenerative, and inflammatory disorders, as well as anti-diabetic, anticancer, antiviral, and immuno-stimulatory effects. Sales of elderberry supplements skyrocketed to $320 million over the year 2020, according to an American Botanical Council (ABC) report, which is attributable to the purported immune-enhancing effects of elderberry. In the current review, the chemical composition of the polyphenolic content of the European elderberry (Sambucus nigra) and the American elderberry (Sambucus canadensis), as well as the analytical techniques employed to analyze, characterize, and ascertain the chemical consistency will be addressed. Further, the factors that influence the consistency of the polyphenolic chemical composition, and hence, the consistency of the health benefits of elderberry extracts will be presented. Additionally, adulteration and safety as factors contributing to consistency will be covered. The role of elderberry in enhancing human health alone with the pharmacological basis, the cellular pathways, and the molecular mechanisms underlying the observed health benefits of elderberry fruit extracts will be also reviewed.

A CROSS-SECTIONAL STUDY: PERCEPTION AND CONSUMPTION BEHAVIOR ABOUT IMMUNITY BOOSTER SAMBUCUS SP. PRODUCTS (AZERBAIJAN, GEORGIA, UZBEKISTAN)

Objective: The aim of this cross-sectional study was to measure and determine the difference between perception and consumption changes of elderberry products in Azerbaijan (AZ), Georgia (GEO) and Uzbekistan (UZB) countries. Material and Method: A questionnaire based, cross-sectional, multi country study was conducted by using an online based with consumers of pharmacies, drug stores and shops where had food supplement category between April and August 2021. Result and Discussion: The majority of responders belong to 31-50 age group, and higher gender profile was on female part, 85%. The results showed that end users of consumed products were children (51%) and older family members (39%) in the average data of 3 countries. Elderberry products were classified as expensive products but were consumed high amount during the pandemic. During the pandemic, immune boosting had been in prior place of individual healthcare, and prophylactic approach had become more important than earlier. This is the first study in Azerbaijan, Georgia and Uzbekistan as a digital survey based, cross- sectional study. © 2022 Authors. All rights reserved.

Plant lectins as versatile tools to fight coronavirus outbreaks.

The S protein forming the homotrimeric spikes of pathogenic beta-coronaviruses, such as MERS-CoV, SARS-CoV and SARS-CoV-2, is a highly glycosylated protein containing mainly N-glycans of the complex and high-mannose type, as well as O-glycans. Similarly, the host cell receptors DPP4 for MERS-CoV and ACE2 for SARS-CoV and SARS-CoV-2, also represent N- and O-glycosylated proteins. All these glycoproteins share common glycosylation patterns, suggesting that plant lectins with different carbohydrate-binding specificities could be used as carbohydrate-binding agents for the spikes and their receptors, to combat COVID19 pandemics. The binding of plant lectins to the spikes and their receptors could mask the non-glycosylated receptor binding domain of the virus and the corresponding region of the receptor, thus preventing a proper interaction of the spike proteins with their receptors. In this review, we analyze (1) the ability of plant lectins to interact with the N- and O-glycans present on the spike proteins and their receptors, (2) the in vitro and in vivo anti-COVID19 activity already reported for plant lectins and, (3) the possible ways for delivery of lectins to block the spikes and/or their receptors.

The Pros and Cons of Using Elderberry (Sambucus nigra) for Prevention and Treatment of COVID-19.

Background: The novel severe acute respiratory syndrome coronavirus 2 emerged in 2019. Health-care systems around the world are looking for alternative prevention and treatment remedies. Herbal supplements are popular among consumers as a complementary method to prevent and treat illnesses. One of them is Sambucus nigra. Methods: We searched for related articles in Scopus, Web of Science, PubMed, Google Scholar, and the Directory of Open Access Journals using the following keywords: elderberry, S. nigra, and COVID-19. Results: Elderberry has antiviral properties due to its ability to modulate inflammatory cytokines. The current evidence suggests elderberry is appropriate for the prevention and initial treatment of viral disease. Concerns have been raised that elderberry may overstimulate the immune system, increasing the risk of a cytokine storm. There is not yet enough evidence to support this claim. Conclusions: For COVID-19 patients, further research is required since elderberry may provoke a cytokine storm if administered therapeutically.

Attitudes and approaches towards COVID-19 management among the public and pharmacists in Northern Cyprus

Purpose: To study the attitudes and approaches towards COVID-19 management among the public and pharmacists in Northern Cyprus. Method: Questionnaire were administered face-to-face and online to volunteer pharmacists and other members of the public, after receiving approval from the Near East University Ethics Boards. Responses to the questionnaire were evaluated statistically.

Inhibition of Human Respiratory Influenza A Virus and Human Betacoronavirus-1 by the Blend of Double-Standardized Extracts of Aronia melanocarpa (Michx.) Elliot and Sambucus nigra L.

Viral and bacterial diseases are among the greatest concerns of humankind since ancient times. Despite tremendous pharmacological progress, there is still a need to search for new drugs that could treat or support the healing processes. A rich source of bioactive compounds with antiviral potency include plants such as black chokeberry and elderberry. The aim of this study was to assess the in vitro antiviral ability of an originally designed double-standardized blend of extracts from Aronia melanocarpa (Michx.) Elliot and Sambucus nigra L. (EAM-ESN) or separated extracts of A. melanocarpa (EAM) or S. nigra (ESN) against four human respiratory tract viruses: influenza A virus (A/H1N1), betacoronavirus-1 (HCoV-OC43) belonging to the same ß-coronaviruses as the current pandemic SARS-CoV-2, human herpesvirus type 1 (HHV-1), and human adenovirus type 5 (HAdV-5). Antiviral assays (AVAs) were used to evaluate the antiviral activity of the plant extracts in a cell-present environment with extracts tested before, simultaneously, or after viral infection. The virus replication was assessed using the CPE scale or luminescent assay. The EAM-ESN blend strongly inhibited A/H1N1 replication as well as HCoV-OC43, while having a limited effect against HHV-1 and HAdV-5. This activity likely depends mostly on the presence of the extract of S. nigra. However, the EAM-ESN blend possesses more effective inhibitory activity toward virus replication than its constituent extracts. A post-infection mechanism of action of the EAM-ESN make this blend the most relevant for potential drugs and supportive treatments; thus, the EAM-ESN blend might be considered as a natural remedy in mild, seasonal respiratory viral infections.

Therapeutic potential of plant secondary metabolites in treatment of respiratory viral diseases: A review

Respiratory viral infections are a major public health concern because of their global occurrence, ease of spread and considerable morbidity and mortality. Medical treatments for viral respiratory diseases primarily involve providing relief from symptoms like pain and discomfort rather than treating the infection. Very few antiviral medications have been approved with restrictive usage, high cost, unwanted side effects and limited availability. Plants with their unique metabolite composition and high remedial values offer unique preventive and therapeutic efficacy in treatment of viral infections. The present review is focused on the types and mode of action of plant secondary metabolites that have been used successfully ί in the treatment of infections caused by respiratory viruses like Influenza, SARS, MERS, RSV etc. Plant metabolites such as phenolics, alkaloids, terpenoids and oligosaccharides inhibit attachment and entry of the virus. Others such as flavonoids, viz quercetin and baicalein, alkaloids viz sanguinarine, berberine and emetine, specific lipids and fatty acids prevent viral replication and protein synthesis. These metabolites have the potential to be used as lead molecules that can be optimized to develop potent drugs for effectively combating pandemics caused by respiratory viruses.

Antiviral activity of plant juices and green tea against SARS-CoV-2 and influenza virus.

Respiratory viruses pose a significant threat to global health. They initially infect the naso- and oropharyngeal regions, where they amplify, cause symptoms, and may also be transmitted to new hosts. Preventing initial infection or reducing viral loads upon infection might soothe symptoms, prevent dissemination into the lower airways, or transmission to the next individual. Several natural products have well-described direct antiviral activity or may ameliorate symptoms of respiratory infections. We thus analyzed the potential of plant-derived products to inactivate respiratory viral pathogens and determined the antiviral activity of black chokeberry (Aronia melanocarpae [Michx.] Elliott), elderberry (Sambucus nigra L.), and pomegranate (Punica granatum L.) juice, as well as green tea (Camellia sinensis [L.] Kuntze) on the infectivity of the surrogate-modified vaccinia virus Ankara, and the respiratory viruses severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (IAV), and adenovirus Type 5. Black chokeberry and pomegranate juice, and green tea reduced SARS-CoV-2 and IAV titers by ≥80% or ≥99%. This suggests that oral rinsing with these products may reduce viral loads in the oral cavity which might prevent viral transmission.

Primary care experience on Stimunex® gocce in children with recurrent respiratory infections: a real-world study during the COVID-19 pandemic era.

BACKGROUND: Respiratory infections (RI) significantly burden society, mainly when there are recurrent respiratory infections (RRI). Thus, there is a need to prevent RI in clinical practice. In this regard, the modulation of the immune system and resolution of the inflammatory cascade could represent an ideal way to prevent RI. Stimunex® gocce, a multicomponent food supplement, contains Sambucus nigra extract, ß-glucan, Zinc, and Vitamin D3. This study investigated its ability to prevent RRI in children using a real-world setting: the pediatric primary care. MATERIALS AND METHODS: Two hundred and ninety-eight children with RRI were enrolled in the current study. The food supplement was randomly prescribed to 160 children with RRI daily for 4 months (Active group); the remaining 138 children with RRI were treated only with standard therapy for RI (Control group). The number and duration of RI, parental perception of symptom severity and treatment efficacy, use of medications, and school and working absence were evaluated. RESULTS: Children treated with Stimunex® gocce had significantly less RI than the Control group, both concerning upper and lower RI (p˂0.001 and 0.003, respectively) during the follow-up period. Moreover, children in the Active group experienced shorter RI duration during the treatment and follow-up phases (p˂0.001 for both). In addition, parents of treated children perceived less severe symptoms and better treatment efficacy during the first and follow-up phases (p˂0.001 for all). The food supplement was well tolerated and there was no adverse event. CONCLUSIONS: The current real-world study demonstrated that Stimunex® gocce supplementation in children with RRI might safely prevent RI episodes and reduce RI duration. These outcomes should be highlighted as obtained during the COVID-19 pandemic era, characterized by a dramatic reduction of RI.

Natural Products and Their Promise Against COVID 19: Review

Background: Since the beginning of medical history, plants have been exemplary sources of a variety of pharmacological compounds that are still used in modern medication. Respiratory infections are a serious and persistent global health problem, most acute and chronic respiratory infections are caused by viruses, whose ability to mutate rapidly may result in epidemics and pandemics, as seen recently with MERS-COV (2012) and SARS-COV-2 (2019), the latter causing coronavirus disease 2019 (COVID-19). Methods: This study aims to highlight the tremendous benefits of plants that have been widely used as dietary supplements or traditional treatment for various respiratory infections, with a focus on the most effective constituents and studies that revealed their activities against COVID-19. Results: Several traditional plants and their phytoconstituents have shown activity against respiratory viruses, including SARS-COV-2. The presented plants are Nigella sativa, Punica granatum, Panax ginseng, Withania somnifera, Glycyrrhiza glabra, Curcuma longa, Zingiber officinale, Camellia sinensis, Echinacea purpurea, Strobilanthes cusia, Stephania tetrandra, and genus Sambucus. Conclusion: The data discussed in this review can encourage carrying out in-vivo studies that may help in the discovery of herbal leads that can be feasibly used to alleviate, prevent or treat COVID-19 infection.

A cross-sectional survey of herbal remedy taking to prevent COVID-19 in Turkey. (COVID-19 dedicated issue.)

The Coronavirus disease 2019 (Covid-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has led to unprecedented challenges for human life. During this pandemic, Turkish people have used various herbal remedies for both the prevention of Covid-19 and the alleviate of its symptoms. The present study aimed to investigate the herbal remedies used to prevent Covid-19 in Turkey and to determine whether the usage of herbal remedies was associated with sociodemographic properties. A cross-sectional study using an online questionnaire was conducted between November and December 2020. A total of 871 individuals (15 years of age or older) who lived in various provinces of Turkey participated in this study. Analysis was made in SPSS version 26.0 software using the descriptive statistics and appropriate tests of statistical significance for the comparisons. About 54.4% (n=474) of the participants reported that they have used herbal remedies during the pandemic period. We identified a total of 45 plant species, the most frequently cited were ginger (Zingiber officinale Roscoe), linden (Tilia spp.), elderberry (Sambucus nigra L.), sage (Salvia spp.), and rosehip (Rosa canina L.), respectively. It has been found that the usage of herbal remedies was associated with several demographic variables. A considerable proportion of the participants reported the use of herbal remedies in order to prevent disease. This paper demonstrated the potential herbal remedies that can be used against Covid-19. Further research should be carried out to evaluate the efficacy of these medicinal plants and should control the flow of misleading information.

Potential immunomodulatory and antiviral food effect in the context of COVID-19 pandemic

Background: Up to date drug-based treatments for COVID-19 have not been approved. The most effective way to face this public health problem is prevention with adequate nutrition, hygiene, and protection measures. Food has historically been used by people to improve their nutrition and complement the treatment or prevention of diseases. The various bioactive compounds of some foods are known, which in experimental studies demonstrated their antiviral and immunomodulatory action.

Medicinal plants preferences for the treatment of COVID-19 symptoms in Central and Eastern Anatolia

Aim of study: This study aimed to determine the medicinal plant use preferences of herbalists' customers against the COVID-19 symptoms during pandemic period. Area of study: The study was carried out in nine provinces located in the Central and Eastern Anatolia Region of Turkey and the herbalists selling medicinal plants. Material and methods: Data on 35 plants from 373 customers and 49 herbalists were collected between April 2020 and December 2020. Relative Frequency of Citation (RFC) and Fidelity Level (FL) quantitative indices were used to measure the use, cultural significance, and specificity of plants. Main results: The highest RFC was found for Thymus spp. (0.59). It was followed by Ceratonia siliqua L. (0.56), Zingiber officinale Roscoe (0.56), and Mentha pulegium L. (0.50), respectively. The plants in the study area with a high FL were Zingiber officinale (84.83%) for cough, Thymus spp. (80.95%) for fever, Mentha pulegium (76.47%) for nausea-vomiting. Sambucus nigra L., Echinacea angustifolia DC., and Thymus spp. were the plants whose sales/demand increased the most during the pandemic period. Highlights: It was understood that there was a significant increase in the sales of species such as Sambucus nigra, Echinacea angustifolia, and Thymus spp., during the pandemic period. This situation showed that there was a consensus among the public that these plants were effective against COVID-19 symptoms.

An Exploratory Review of Potential Adjunct Therapies for the Treatment of Coronavirus Infections.

OBJECTIVE: The purpose of this exploratory review was to examine vitamin D, zinc, vitamin A, elderberry (Sambucus nigra), garlic (Allium sativum), licorice (Glycyrrhiza glabra), stinging nettle (Urtica dioica), N-acetylcysteine, quercetin, and selenium as potential adjunct therapies for the treatment of coronavirus infections. METHODS: A search of PubMed was performed for articles published from 2005 to 2021. Keywords searched were "zinc," "vitamin A," "vitamin D," "Sambucus nigra," "Allium sativum," "Glycyrrhiza glabra," "Urtica dioica," "N-acetylcysteine," "quercetin," "selenium," and "coronavirus." RESULTS: There were 47 articles selected for this review. Findings included that vitamin D, zinc, vitamin A, S. nigra, A. sativum, G. glabra, U. dioica, N-acetylcysteine, quercetin, and selenium have been shown to produce antiinflammatory, immunostimulatory, or antiviral effects that may enhance the actions of standard therapeutics for the treatment of coronavirus infections. Specific to effects against COVID-19, we found research articles related to the effects of only vitamin D, zinc, G. glabra, quercetin, and selenium. CONCLUSION: We identified nonpharmaceutical supplements (vitamin D, zinc, vitamin A, S. nigra, A. sativum, G. glabra, and U. dioica) which may have potential to provide support for those with coronavirus infections. However, rigorous clinical studies need to be performed before any clinical recommendations can be made.

Elderberry for prevention and treatment of viral respiratory illnesses: a systematic review.

BACKGROUND: Elderberry has traditionally been used to prevent and treat respiratory problems. During the COVID-19 pandemic, there has been interest in elderberry supplements to treat or prevent illness, but also concern that elderberry might overstimulate the immune system and increase the risk of 'cytokine storm'. We aimed to determine benefits and harms of elderberry for the prevention and treatment of viral respiratory infections, and to assess the relationship between elderberry supplements and negative health impacts associated with overproduction of pro-inflammatory cytokines. METHODS: We conducted a systematic review and searched six databases, four research registers, and two preprint sites for studies. Two reviewers independently assessed studies for inclusion, extracted data from studies, assessed risk of bias using Cochrane tools, and evaluated certainty of estimates using GRADE. Outcomes included new illnesses and the severity and duration of illness. RESULTS: We screened 1187 records and included five randomized trials on elderberry for the treatment or prevention of viral respiratory illness. We did not find any studies linking elderberry to clinical inflammatory outcomes. However, we found three studies measuring production of cytokines ex vivo after ingestion of elderberry. Elderberry may not reduce the risk of developing the common cold; it may reduce the duration and severity of colds, but the evidence is uncertain. Elderberry may reduce the duration of influenza but the evidence is uncertain. Compared to oseltamivir, an elderberry-containing product may be associated with a lower risk of influenza complications and adverse events. We did not find evidence on elderberry and clinical outcomes related to inflammation. However, we found evidence that elderberry has some effect on inflammatory markers, although this effect may decline with ongoing supplementation. One small study compared elderberry to diclofenac (a nonsteroidal anti-inflammatory drug) and provided some evidence that elderberry is as effective or less effective than diclofenac in cytokine reduction over time. CONCLUSIONS: Elderberry may be a safe option for treating viral respiratory illness, and there is no evidence that it overstimulates the immune system. However, the evidence on both benefits and harms is uncertain and information from recent and ongoing studies is necessary to make firm conclusions.

Wild Sambucus nigra L. from north-east edge of the species range: A valuable germplasm with inhibitory capacity against SARS-CoV2 S-protein RBD and hACE2 binding in vitro.

Berries and flowers of Sambucus nigra L. tree are well known for their ability to mitigate symptoms of upper respiratory disorders related to reported antiviral properties. Industrial application and commercial cultivation of S. nigra is largely limited to a few widely grown cultivars. Restricted genetic diversity of cultivated S. nigra can be disadvantageous if new industrial applications are discovered. In this study wild S. nigra populations located on the north-east edge of the species natural range were explored by assessing genetic origin, berry and flower anti-oxidative potential, and berry rutin content. Best performing wild S. nigra extracts were selected for an assessment of previously unreported biological activity- inhibitory capacity against SARS-CoV2 S1 protein receptor binding domain (RBD) binding to recombinant human angiotensin -converting enzyme 2 (ACE2) receptor in vitro based on competitive enzyme linked immunosorbent assay (ELISA). Inter-simple sequence repeat (ISSR) marker-based genetic characterization suggested that explored wild S. nigra populations result from wild gene pool expanding northwards with admixture of historically introduced cultivated S. nigra. Average values of total phenolic content, anti-radical activity, and total flavonoids content of wild S. nigra populations did not exceed those of cv. 'Haschberg'. Concentration-dependent inhibition of ACE2-SARS-CoV2 S-protein RBD binding was demonstrated in vitro for elderberry fruits and flowers extracts (IC50 of 1.66 mg DW ml-1 and 0.532 mg DW ml-1, respectively). Wild elderberry fruit extract exhibited higher inhibitory capacity than the extract from berries of cv 'Haschberg'. This study validates the requirement for S. nigra wild germplasm bioprospecting and opens up directions for further research of new anti-SARS-CoV2 industrial applications of S. nigra.

The effects of Sambucus nigra berry on acute respiratory viral infections: A rapid review of clinical studies.

BRIEF OVERVIEW: Collectively the evidence obtained from across five clinical studies involving 936 adults indicate that mono-herbal preparations of Sambucus nigra L. berry (S.nigra), when taken within 48 hours of the onset of acute respiratory viral infection, may reduce the duration and severity of common cold and influenza symptoms in adults. There is currently no evidence to support the use of S.nigra berry for the treatment or prevention of COVID-19. Given the body of evidence from preclinical studies demonstrating the antiviral effects of S.nigra berry, alongside the results from clinical studies involving influenza viral infections included in this review, pre-clinical research exploring the potential effects of S.nigra berry on COVID-19 are encouraged. VERDICT: The evidence included in this review is mostly derived from clinical studies involving adult participants and examining short-term use of commercial formulations of S.nigra berry for up to 16 days. Findings from included studies suggest that mono-herbal preparations of S.nigra berry (in extract or lozenge formulation) may reduce influenza-type symptoms, including fever, headache, nasal congestion and nasal mucous discharge in adults, when taken within the first 48 hours of symptom onset. Within 2-4 days of S.nigra treatment, most adult participants experienced significant symptom reduction, by an average of 50%. Evidence regarding the effectiveness of S.nigra berry on the symptom of cough, and need for/use of medicines (including antibiotics) to treat acute respiratory infections, is currently unclear and inconsistent. Adverse events were rare with no serious events reported. Adverse events, reported in two studies, were more common in comparators than in treatments. There is currently no reliable or sufficient scientific evidence to support the use of S.nigra in pregnant or lactating women.

Botanical drugs and supplements affecting the immune response in the time of COVID-19: Implications for research and clinical practice.

In times of health crisis, including the current COVID-19 pandemic, the potential benefit of botanical drugs and supplements emerges as a focus of attention, although controversial efficacy claims are rightly a concern. Phytotherapy has an established role in everyday self-care and health care, but, since botanical preparations contain many chemical constituents rather than single compounds, challenges arise in demonstrating efficacy and safety. However, there is ample traditional, empirical, and clinical evidence that botanicals can offer some protection and alleviation of disease symptoms as well as promoting general well-being. Newly emerging viral infections, specifically COVID-19, represent a unique challenge in their novelty and absence of established antiviral treatment or immunization. We discuss here the roles and limitations of phytotherapy in helping to prevent and address viral infections, especially regarding their effects on immune response. Botanicals with a documented immunomodulatory, immunostimulatory, and antiinflammatory effects include adaptogens, Boswellia spp., Curcuma longa, Echinacea spp., Glycyrrhiza spp., medicinal fungi, Pelargonium sidoides, salicylate-yielding herbs, and Sambucus spp. We further provide a clinical perspective on applications and safety of these herbs in prevention, onset, progression, and convalescence from respiratory viral infections.