In Silico and In vitro Analysis of Phenolic Acids for Identification of Potential DHFR Inhibitors as Antimicrobial and Anticancer Agents.

Background: DHFR is an indispensable enzyme required for the survival of almost all prokaryotic and eukaryotic cells, making it an attractive molecular target for drug design.

Objective: In this study, a combined in silico and in vitro approach was utilized to screen out potential anticancer and antimicrobial agents by using DHFR PDB ID 2W9S (for antimicrobial) and 1U72 (for anticancer).

Methods: Computational work was performed using Maestro Schrodinger Glide software. The DHFR inhibitory activity of the selected compounds was assessed using the DHFR test kit (CS0340-Sigma- Aldrich).

Results: Exhaustive analysis of in silico results revealed that some natural phenolic acids have a good docking score when compared to standards, i.e., trimethoprim and methotrexate, and have astonishing interactions with crucial amino acid residues available in the binding pocket of DHFR, such as Phe 92, Asp 27, Ser 49, Asn 18, and Tyr 98. In particular, digallic acid and chlorogenic acid have amazing interactions with docking scores of -9.9 kcal/mol and -9.6 kcal/mol, respectively, for the targeted protein 2W9S. Docking scores of -10.3 kcal/mol and -10.2 kcal/mol, respectively, for targeted protein 1U72. The best hits were then tested in vitro to evaluate the DHFR inhibitory activity of the compounds. DHFR inhibition activity results are in correlation with molecular docking results.

Conclusion: In silico and in vitro results confirmed the good binding and inhibitory activity of some phenolic acids to the modeled target proteins. Among all the studied natural phenolic acids, chlorogenic acid, digallic acid, and rosmarinic acid appeared to be the most potential leads for future chemical alteration. This study can provide significant speculative guidance for the design and development of potent DHFR inhibitors in the future by using these compounds as leads.