11:15 AM - 11:30 AM
[3Ba-09] Development of glycyrrhizin purification method using solubility-based separation.
Keywords:Glycyrrhiza glabra, glycyrrhizin, solubility-based separation
[Purpose] Glycyrrhizin (GL) contained in the root of licorice (Glycyrrhiza glabra) is a medicinal herbal compound with diverse bioactivities such as anti-inflammatory and antimicrobial activities. GL is a triterpenoid saponin molecule containing two glucuronic acid residues. We have developed a simple purification method of soyasaponins from the methanol extract of the whole soybean flour using borax solution, which is useful for the pretreatment purification before HPLC (Anal. Sci. 2019). This method is based on the cis-diol group properties, and was also seemed to be useful for GL.
[Methods] The recovery rate and purity of GL were determined by reversed-phase HPLC (RP-HPLC) and the whole dry weight of the purified samples.
[Results] Although GL is low soluble in water, it can be easily solved in borax solution and can be re-precipitated when acidified. Methanol extract of the licorice powder (Fr.A; 8.5% pure) was solubilized in the borax solution and precipitated by dil. HCl to remove the high polar impurities to obtain Fr.B (31% pure). Then, Fr.C (40% purity) was obtained through Sep-Pak C18 column to remove the low polar impurities, and finally purified to Fr.D (>90% purity) by RP-HPLC. However, the total recovery rate was reduced to ca.10% of Fr.A by the column purifications. Then, the ammonia water extract of the licorice (Fr.I; 6.7% purity) was prepared to reduce the low polar impurities in the initial stage. Fr.I was solubilized in the borax solution and precipitated by dil. HCl to remove the high polar impurities, and Fr.II (70% purity, 70% recovery) was finally obtained without column purifications.
[Methods] The recovery rate and purity of GL were determined by reversed-phase HPLC (RP-HPLC) and the whole dry weight of the purified samples.
[Results] Although GL is low soluble in water, it can be easily solved in borax solution and can be re-precipitated when acidified. Methanol extract of the licorice powder (Fr.A; 8.5% pure) was solubilized in the borax solution and precipitated by dil. HCl to remove the high polar impurities to obtain Fr.B (31% pure). Then, Fr.C (40% purity) was obtained through Sep-Pak C18 column to remove the low polar impurities, and finally purified to Fr.D (>90% purity) by RP-HPLC. However, the total recovery rate was reduced to ca.10% of Fr.A by the column purifications. Then, the ammonia water extract of the licorice (Fr.I; 6.7% purity) was prepared to reduce the low polar impurities in the initial stage. Fr.I was solubilized in the borax solution and precipitated by dil. HCl to remove the high polar impurities, and Fr.II (70% purity, 70% recovery) was finally obtained without column purifications.