Molecular structure, interactions, and antimicrobial properties of curcumin-PLGA Complexes—a DFT study

Density functional calculations are performed to study the molecular structure, interactions, and antimicrobial activity of curcumin-poly lacto glycolic acid (Cur-PLGA) complexes. The calculations are performed on curcumin (Cur), glycolic acid (SSC and AAT conformers), lactic acid (LA), Cur-SSC, Cur-AAT, Cur-LA, and Cur-PLGA complexes using dispersion corrected M06-2X functional with 6–31 + G* basis set. The condensed Fukui functions of Cur are calculated to identify the favorable reactive sites. Inter- and intramolecular H–bond interactions are analyzed in detail through natural bond orbital, Atoms in Molecule, and Reduced density gradient analyses. The interaction energy values indicate that the interaction between Cur and AAT is stronger than the other studied complexes. Further, our calculations show that the PLGA interacted with Cur is having lower LUMO energy and density values. This indicates that the antimicrobial activity is high in this complex.