Flavonoids from Ouratea staudtii Van Tiegh. (ex Keay) (Ochnaceae)

The procedure of yielding flavonoids from the Ouratea staudtii Van Tiegh. (Ochnaceae) plants is discussed. Ochnaceae is commonly found from Western Nigeria to Cameroon. Chemical investigations of Ouratea species have revealed the presence of biflavonoids and diterpenoids. Dried plant leaves were extracted with MeOH at room temperature and the extract was concentrated and solubilized in Et2O. The insoluble phase was chromatographed on a Sephadex LH-20 gel column using MeOH as eluent and 540 fractions were collected. All the fractions were monitored and combined by TLC similarity and then purified by chromatographic process, recrystallization and precipitation. This procedure yielded flavonoids such as lophirone, amentoflavone, ochnaflavone, bilobetin, podocarpusflavone-A, and agathisflavone. The structures of all these isolated compounds were established by comparing physical and spectroscopic properties including mass spectrometry and NMR spectroscopy.