Study on Extraction and Purification of Apigenin and the Physical and Chemical Properties of Its Complex with Lecithin

Background: The apigenin has important medicinal value. However, the low solubility of apigenin in water significantly reduced its application. Objective: In this study, the apigenin was extracted, and the complex of apigenin and lecithin was obtained by the solvent method and its physical and chemical properties were investigated. Materials and Methods: The apigenin was extracted from the leaves of Adinandra nitida. Afterward, its apigenin was obtained by hydrolysis and recrystallization. The solvent method was used to synthesis the complex of apigenin and lecithin. Tetrahydrofuran was used as the solvent. The physicochemical properties of the complex were investigated by the various methods such as ultraviolet (UV)‑visible spectrometry, infrared spectrometry (IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X‑ray diffractometry. Results: No distinct difference was examined between the complex and physical mixture according to the UV analysis. While the result of Fourier transform‑IR analysis indicated the characteristic absorption peaks of apigenin was subdued by the absorption peaks of lecithin. SEM showed the irregular form of the complex. In the DSC thermogram of the complex, the characteristic endothermic peak belonging to apigenin disappears, and the apparent amorphous properties are shown in the X‑ray X‑diffractograms of the complex. Conclusion: The synthetic process does not break the conjugated structure of apigenin. The complex is held together by Hydrogen bonding and van der Waals force and processes new physical and chemical characteristics. The industrial application of apigenin might be enhanced by the increase of the bioavailability.