Extraction and purification of formonometin from Trifolium pratense L: Physicochemical properties of its complex with lecithin

摘要

Purpose: To isolate formononetin from Trifolium pratense L. (red clover), prepare its complex with lecithin foe enhanced solubility and evaluate its physicochemical properties. Methods: Formononetin was extracted from red clover. The complex of formononetin with lecithin was prepared by solvent method in a ratio of 2.5:1.0 (lecithin : formononetin). The physicochemical properties of the complex were investigated by ultraviolet-visible spectrometry (UV/Vis), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and x-ray diffractometry (XRD). Results: UV data showed that there was no significant difference (p 0.05) between the peak intensity of the physical mixture and the complex, while FT-IR analysis indicated interaction between formononetin and lecithin. SEM showed that formononetin was successfully integrated in the structure of lecithin. DSC thermograms of the complex mainly demonstrated that the presence of lecithin caused the disappearing of characteristic endothermal peaks of formononetin, while x-diffractograms indicate that the crystalline peak of formononetin was absent in the complex. Conclusion: The complex formed is held together by non-covalent-bonds and thus demonstrates new physical and chemical characteristics.