Theoretical study on inhibitability of some natural alkaloids against influenza virus hemagglutinin and SARS‐CoV‐2 main protease

Berberine (V1), lycorine (V2), hemanthamine (V3), aloperin (V4), dendrobine (V5) possess structural frameworks resembling known anti‐influenza and anti‐SARS‐CoV‐2 drugs, thus subjected for a computational screening. Their quantum properties were examined using density functional theory (DFT); the ligand‐protein inhibitability was evaluated using molecular docking simulation; physicochemical properties were obtained from QSARIS‐based analysis in reference to Lipinski's rule of five; pharmacokinetic parameters were assessed by ADMET‐based analysis. DFT calculations indicate that there are no abnormal bonding constraints observed; NBO analysis suggests all possessing favorable electric configurations for intermolecular inhibition. Regarding ligand‐2VIU, the order for static inhibitability is V3‐2VIU > V2‐2VIU > V1‐2VIU > V5‐2VIU > V4‐2VIU; Regarding ligand‐6LU7, the corresponding order follows: V2‐6LU7 > V3‐6LU7 > V1‐6LU7 > V5‐6LU7 > V4‐6LU7. An exceptional hydrophilic bonding (π‐cation) with the associated Gibbs free energy of ‐10.9 kcal.mol‐1 is detected in inhibitory complex V1‐2VIU. QSARIS‐based analysis reveals that all the candidates are highly bio‐compatible. ADMET‐based analysis specifies V2 and V3 as being safe and suitable for the use as orally administrated drugs. The results encourage further investigations for more in‐depth mechanisms and experimental validations, such as molecular dynamics simulation and in vitro enzyme assays.