Characterization and DPPH Radical Scavenging Activity of Gallic Acid-Lecithin Complex

Purpose: To investigate the physicochemical properties and DPPH radical scavenging activity of gallic acid–lecithin complex
Methods: The complex of gallic acid with lecithin was prepared by solvent method. The physicochemical properties of the complex were investigated by ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and x-ray diffractometry (XRD). Antioxidant activity was examined by 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay.
Results: The UV and IR spectra of the complex showed an additive effect of gallic acid and lecithin, in which the characteristic absorption peaks of gallic acid and lecithin were retained. SEM suggests that gallic acid was dispersed into lecithin while DSC and XRD results for the complex mainly showed the presence of lecithin with the characteristic peaks for gallic acid absent. At all concentrations of the complex (0.2 - 1.0 mg/mL), the DPPH radical scavenging activity of the complex was higher than that of the reference antioxidant, butylated hydroxytoluene (BHT).
Conclusion: Gallic acid and lecithin in the complex are combined by a non-covalent bond, and did not form a new compound. The complex is an effective scavenger of DPPH radicals.