Antimicrobial biflavonoids from the aerial part of Ouratea sulcata

Investigation of the aerial parts of Ouratea sulcata led to the isolation of a biflavonoid named sulcatone A, together with the known compounds, 3-hydroxy-2,3-dihydroapigenyl-[I-4′,O,II-3′]-dihydrokaempferol, amentoflavone, lophirone A, agathisflavone, stigmasterol and stigmasteryl-3-O-β-d-glucopyranoside. The structure of the compound was assigned as apigenyl-[I-4′,O,II-3′]-dihydrokaempferol, by means of spectroscopic analysis. Sulcatone A and 3-hydroxy-2,3-dihydroapigenyl-[I-4′,O,II-3′]-dihydrokaempferol exhibited significant in vitro antimicrobial activities against a range of microorganisms.