Flavonoids from Lonchocarpus campestris (Leguminosae)

A new flavone named 3,4',5,6-tetramethoxy-[2, 3:7,8] furanoflavone besides the known flavonoids (2S,3R,4S)-3,4,5,8-tetramethoxy-[2,3:6,7]-furanoflavan, 3,6-dimethoxy-2,2-dimethylcromene-[2,3:7,8]-flavone, 3,5,6-trimethoxy-[2,3:7,8]-furanoflavone, 2,4',4,5-tetramethoxy-[2,3:6,7]-furanodihydroaurone, (2R,3S,4S)-3,4,5,6-tetramethoxy-[2,3:7,8]-furanoflavan and 3',4'-methylenedioxy-5,6-dimethoxy-[2,3:7,8]-furanoflavone were isolated from the root barks of Lonchocarpus campestris. The complete 1H and 13C NMR assignments of the new furan flavonoid was performed using 1D and 2D pulse sequences, including COSY, HMQC and HMBC experiments. (author)