Botanical Drugs and Supplements Affecting the Immune Response in the Time of COVID-19: Implications for Research and Clinical Practice

Abstract

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 selfcare and health care, and 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, and specifically regarding their effects on immune response. Botanicals with a documented immunomodulatory, immunostimulatory, and anti-inflammatory effect 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.

Safety Review of Herbs and Supplements in Heart Disease, Diabetes, and COVID-19

“…SARS-CoV-2 binds directly to angiotensin converting enzyme 2 (ACE2) for subsequent entry into cells [10,12]. Infected cells respond to the virus by generating pro-inflammatory cytokines and chemokines that sometimes lead to a cytokine storm which aggravates the disease [10,12,13]. Those with certain underlying health conditions such as respiratory disease, cardiovascular disease, and diabetes as well as older individuals seem to be at a higher risk for developing severe complications from the infection [14,15].…”

“…Echinacea has antiviral and immunomodulatory effects that seems to be promising against COVID-19 [13,26]. Several studies have investigated the benefits of echinacea in treating and preventing respiratory tract infections such as the common cold, but not for other health purposes [27].…”

“…Frequently recommended by herbalists, licorice has recently shown to be the herb most frequently used for COVID-19 treatment [41,42]. Several review articles have discussed the potential effectiveness of licorice in treating COVID-19 for its antiviral, anti-inflammatory, spasmolytic, and expectorant effects [9,10,[12][13][14]. Some in vitro studies showed that the active component glycyrrhizin inhibits the replication of SARS-coronavirus (SARS-CoV) [43,44].…”

“…Turmeric has antiviral and anti-inflammatory effects that might benefit COVID-19 patients [10,13]. It has also been hypothesized that the antioxidant effects of turmeric benefit diabetic patients during COVID-19 infection [67].…”

In vitroscreening of herbal medicinal products for their supportive curing potential in the context of SARS-CoV-2

“…Testing the effectiveness of different drug types used previously in the treatment of other diseases is here one strategy to accelerate the development. Herbal medicinal products have the potential to interfere with various steps of the viral replication cycle (Brendler and Al-Harrasi, 2020; Mani et al, 2020). Besides, they have been reported to exhibit an anti-inflammatory and immune modulating potential and thus may also be supportive in prevention or attenuation of mild to moderate SARS-CoV-2 infections (Glatthaar-Saalmüller B, 2011; Seibel et al, 2015; Seibel et al, 2018).…”