Two unusual rotenoid derivatives, 7a-O-methyl-12a-hydroxydeguelol and spiro-13-homo-13-oxaelliptone, from the seeds of Derris trifoliata - Yenesew, A; Kiplagat, J T; Derese, S; Midiwo, J O; Kabaru, J M; Heydenreich, M; Peter, M G (Phytochemistry, 2006)