In vitro Screening of Herbal Medicinal Products for Their Supportive Curing Potential in the Context of SARS-CoV-2

Abstract

COVID-19 herbal medicinal products may have the potential for symptom relief in nonsevere or moderate disease cases. In this in vitro study we screened the five herbal medicinal products Sinupret extract (SINx), Bronchipret thyme-ivy (BRO-TE), Bronchipret thyme-primula (BRO TP), Imupret (IMU), and Tonsipret (TOP) with regard to their potential to (i) interfere with the binding of the human angiotensin-converting enzyme 2 (ACE2) receptor with the SARS-CoV-2 spike S1 protein, (ii) modulate the release of the human defensin HBD1 and cathelicidin LL-37 from human A549 lung cells upon spike S1 protein stimulation, and (iii) modulate the release of IFN-γ from activated human peripheral blood mononuclear cells (PBMC). The effect of the extracts on the interaction of spike S1 protein and the human ACE2 receptor was measured by ELISA. The effects on the intracellular IFN-γ expression in stimulated human PBMC were measured by flow cytometry. Regulation of HBD1 and LL-37 expression and secretion was assessed in 25 d long-term cultured human lung A549 epithelial cells by RT-PCR and ELISA. IMU and BRO-TE concentration-dependently inhibited the interaction between spike S1 protein and the ACE2 receptor. SINx, TOP, and BRO-TE significantly upregulated the intracellular expression of anti-viral IFN-γ from stimulated PBMC. Cotreatment of A549 cells with IMU or BRO TP together with SARS-CoV-2 spike protein significantly upregulated mRNA expression (IMU) and release of HBD1 (IMU and BRO TP) and LL-37 (BRO TP). The in vitro screening results provide first evidence for an immune-activating potential of some of the tested herbal medicinal extracts in the context of SARS-CoV-2. Whether these could be supportive in symptom relief or curing from SARS-CoV-2 infection needs deeper understanding of the observations.

Chemical Composition of Thyme (Thymus vulgaris) Extracts, Potential Inhibition of SARS-CoV-2 Spike Protein–ACE2 Binding and ACE2 Activity, and Radical Scavenging Capacity

“…The results from our study supported a previous study, in which medicinal extract containing both thyme and ivy was inhibit the Sprotein binding interaction. 8 Flavonoids contain multiple functional groups that may inhibit interaction between ACE2 and the S-protein of SARS-CoV-2. For example, the resorcinol moiety in ring A of flavonoids may inhibit hydrogen bonds between ACE2 and the S-protein.…”

“…Herbal medicinal products containing thyme and other herbs were shown to inhibit the S-protein and ACE2 interaction in vitro. 8 Sample Extraction. A dried thyme sample was pulverized and filtered through a 40-mesh sieve prior to the extraction.…”

“…Herbal medicinal products containing thyme and other herbs were shown to inhibit the S-protein and ACE2 interaction in vitro. However, individual thyme extract has not yet been studied for its inhibitory effect on SARS-CoV-2. Our previous research has demonstrated that clove extracts in water and ethanol inhibited the S-protein binding with ACE2 and the ACE2 activity .…”

Contribution of Symptomatic, Herbal Treatment Options to Antibiotic Stewardship and Microbiotic Health

“…Both trials showed a significantly faster reduction of coughing fits, in comparison to the placebo, as well as a faster regression of bronchitis-related symptoms and higher responder rates with the herbal product [ 95 , 96 ]. In addition to anti-inflammatory and -viral [ 125 ] effects, the thyme-ivy/thyme-primula combinations also showed mucus-regulatory effects in acute and chronic bronchitis and bronchoalveolitis [ 126 , 127 , 128 ].…”

Efficacy and Effectiveness of the Herbal Medicinal Product BNO 1016 in the Management of Acute Rhinosinusitis in the Context of Antibiotic Stewardship

“…MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions, or products referred to in the content. exerted well-documented mucosecretolytic and secretomotoric [6][7][8][9], anti-inflammatory [10,11] as well as antiviral [12,13] effects in vitro and in vivo. But what about clinical, human data to evaluate the benefit of a medicinal product?…”