Abstract:

The ionic liquids have been known as “green” or “environmentally friendly” solvents and show potentials to replace traditional solvents. A new approach was set up for the extraction and separation of isoflavonoids from the Rhynchosia volubilis Lour using the 1-butyl-3-methyl tetrafluoroborate([Bmim]BF4) ionic liquid. Three isoflavonoids were obtained from the 70% alcohol extract of Rhynchosia volubilis. Based on the spectra analysis, their structures have been confirmed to be cajanone, 3-[4′-(1″-methoxy)-propoxy]-phenyl-5,7-dihydroxy-isoflavone and Biochanin A, in which the 3-[4′-(1″-methoxy)-propoxy]-phenyl-5,7-dihydroxy-isoflavone is a novel compound. The result had shown that the [Bmim]BF4 could extract isoflavones effectively and selectively. A protocol for determining the content of each component in the isoflavonoid was established. The overall pharmacognosical content of isoflavone was 0.73% using cajanone as the standard and its maximum absorption(270 nm) as the determination wavelength. The average recovery rate and relative standard deviation was 99.94% and 3.66%, respectively. The recycling rate of the ionic liquid was 76.7%.