Derivatives of Betulin and Betulinic Acid Containing a Phosphonate Group-In Silico Studies and Preliminary In Vitro Assessment of Antiviral Activity

Viral diseases affecting both humans and animals are a serious public problem. Chemical modifications of the structure of compounds of natural origin, e.g., betulin, seem to be a promising model in the search for new antiviral agents. The subject of our work was to conduct preliminary tests on the antiviral activity of phosphonic derivatives of betulin and betulinic acid and to assess the pharmacokinetic profile of target compounds. Human (HHV-1, HAdV-5) and animal viruses (BEV, VSV) were used in the in vitro tests. Additionally, this paper presents the results of research using in silico methods (ADMET and molecular docking). Two compounds (betulin 29-phosphonate 3 and 3-(3 ',3 '-dimethylsuccinyl)betulin acid 29-phosphonate 8a) showed antiviral activity against BEV, and compound 3 was also active against HAdV-5. For compound 3, which showed advantageous pharmacokinetic parameters, molecular docking was performed to determine possible interactions with the cellular target HAdV-5 endopeptidase, which plays an important role in various functions of the virus. Selecting the most active derivatives makes it possible to plan tests on an animal model.