Structural and electronic properties of BPA-fructose complex used in boron neutron capture therapy

A density functional investigation on the complexes of p-boronophenylalanine (BPA) with β-d-fructofuranose, as 10B-enriched compounds used in clinical trials for boron neutron capture therapy (BNCT), is reported. The structural and electronic properties of complex I, II, and III, considered as possible configuration models for BPA-fructose complexes, and p-boronophenylalanine molecule are compared. Complex I and II are the most active among calculated compounds, and they are also highly polar molecules comparing with BPA and III. The structural feature of complex III is less affected by attaching the fructose. According to the present calculations, it seems that the fructose moiety contributes activator function to the complex I and II.