Enzyme-Based Antiviral Potential of Cinnamomum verum J. Presl. Essential Oil and Its Major Component ( E )-Cinnamaldehyde.

In the present study, Cinnamomum verum J. Presl. bark essential oil and its main component cinnamaldehyde was evaluated in vitro for neuraminidase (NA), transmembrane serine protease (TMPRSS2), and angiotensin converting enzyme 2 (ACE2) inhibitory activities. The chemical composition of C. verum essential oil was confirmed by both gas chromatography-mass spectrometry (GC/MS), and gas chromatography-flame ionization detection (GC-FID), where 75.9% ( E )-cinnamaldehyde was the major component. The ACE2, NA, and TMPRSS2 enzyme inhibitions of C. verum bark essential oil at 20 μg/mL concentration, and ( E )-cinnamaldehyde (5 μg/mL) were calculated and compared in the range of 54.2-89.9%. Molecular docking results supported that ( E )-cinnam-aldehyde was specific to ACE2 with 89.9% inhibition. Our findings suggest further in vivo studies to confirm the effective and safe use of the essential oil as well as the ( E )-cinnamaldehyde.