Suffrutines A and B: A Pair of Z/E Isomeric Indolizidine Alkaloids from the Roots of Flueggea suffruticosa

Abstract Suffrutines A ( 1 ) and B ( 2 ), a pair of novel photochemical Z / E isomeric indolizidine alkaloids, with a unique and highly conjugated C 20 skeleton, were isolated from the roots of Flueggea suffruticosa. The structures were elucidated by extensive analysis of NMR spectra and single‐crystal X‐ray diffraction. The light‐induced isomerization and hypothetical biogenetic pathway to 1 and 2 , as well as their activity for regulating the morphology of Neuro‐2a cells are also discussed.