Synthesis, crystal structure, spectral characterization and fluorescence studies of salts of α-mangostin with APIs

Abstract

α-Mangostin is a naturally occurring oxygenated xanthonoid isolated from the mangosteen tree (Garcinia mangostana). We report the molecular salts of α-mangostin with the active pharmaceutical ingredients (APIs) metformin (anti-diabetic) and piperazine (anti-helminthic) obtained by solvent assisted grinding method as well as solution crystallization method based on the ΔpKa criterion. The synergistic pharmaceutically active α-mangostin–metformin molecular salt and α-mangostin-hemipiperazine ethanol solvate were characterized by the single crystal X-ray diffraction (SCXRD), vibrational spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The fluorescence properties of the molecular salts are obtained by fluorescence spectroscopy. The molecules in both the crystal forms are stabilized by N+H⋯N, OH⋯O−, N+H⋯O and N+H⋯O−, OH⋯O hydrogen bonding interactions. In the FT-IR spectra characteristic peaks are observed for the protonated amine (NH2+) group piperazinium dication (NH+) respectively indicating formation salts.