Insecticidal bisindole alkaloids from leaves of Tabernaemontana divaricata ' Dwaft '

Six undescribed bisindole alkaloids, namely taberdisines A - F ( 1 - 6 ), were isolated from the leaves of Tabernaemontana divaricata ' Dwaft ' . Among them, alkaloids 1 and 2 were the first examples of strychnos - iboga type alkaloid with both C - C linkage patterns. Alkaloid 3 , a new type of aspidosperma - iboga with a furan -ring, as well as other three undescribed ones was disclosed. Their structures were elucidated by comprehensive spectroscopic analyses. Alkaloids 1 and 5 showed insecticide activity on Sf9 cell and eggs of Spodoptera frugiperda in vivo, which might explain the potential of the plants for insect resistance.