Separation and Identification of Flavonoids in an Extract from the Seeds of Oroxylum indicum by CCC

Abstract

Oroxylum indicum (O. indicum) is widely used as a medicinal plant in China and Japan. The seeds are used as the crude drug “Mu Hu DIE” in China. Flavonoids are present in the seeds of O. indicum. The composition of an ethyl acetate extract of the seeds of O. indicum is completed using high speed analytical counter current chromatography and preparative high‐speed countercurrent chromatography (HSCCC). The HSCCC separation of the extract used a solvent system of hexane/ethyl acetate/methanol/water. Optimal distribution coefficients (K _D ) were determined by use of high performance liquid chromatography (HPLC). An HPLC method was developed to analyse the extract. Using an isocratic elution, effective CCC separation of three components was achieved. A step‐gradient elution was then developed that produced a faster separation with better resolution. Separation of the components was achieved using 20 mg of extract, and the peaks were examined by LC–MS and NMR. The flavonoids, chrysin, and baicalein, were identified. Another flavonoid, possibly baicalein‐7‐o‐glucoside was suspected.

Keywords:

• Flavonoids
• Oroxylum indicum
• HSCC
• Analysis
• Isocratic and gradient elution

Acknowledgments

The authors would like to thank the Chinese government for financial support, Alain Berthod for extensively editing the manuscript, and also. Romulus Technology and Syngenta UK for their kind travel grant.