Mechanistic evaluation of the in vitro antiviral and anti-inflammatory potential of thyme and licorice herbal preparation

CarvenS™ is a herbal syrup formulated with standardized extracts of Thyme (Thymus vulgaris L., Lamiaceae, herba) and Licorice (Glycyrrhiza glabra L. root, Fabaceae) in a Stevia sp.-base, commonly used in Türkiye for the relief of cough, cold, and flu symptoms. This study assessed its in vitro inhibitory potential against angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), neuraminidase (NA), and selected pro-inflammatory mediators including tumor necrosis factor-alpha (TNF-α), cyclooxygenase (COX), and lipoxygenase (LOX), respectively. In addition, the phytochemical profile was determined using high-performance liquid chromatography (HPLC), which revealed the presence of 1.07%(w/v) rosmarinic acid and 0.4%(w/v) glycyrrhizic acid. Enzyme inhibition assays were performed on a microplate system using commercial kits at a final concentration of 20 µg/mL. The syrup showed strong inhibitory effects on ACE2 (81%), TMPRSS2 (89%), and NA (85%). Anti-inflammatory activity was also evident, with inhibition of TNF-α (74.2%), COX-1 (76.3%), COX-2 (78.9%), and 5-LOX (83.1%), respectively. As an overall conclusion, the experimental findings indicate that CarvenS™ demonstrates substantial enzyme inhibitory activity relevant to both antiviral and anti-inflammatory pathways. Further in vivo studies are needed to validate these results and clarify the underlying mechanisms.