ABSTRACT: Fistulains A and B (1 and 2), two novel
bischromones with unique coupling patterns, alone with their
biosynthetic related compound 3, were isolated from the bark
of Cassia fistula. Fistulain A represents a new type of dimeric
chromone alkaloid biogenetically derived from a chromone
and a tricyclic alkaloid through an unusual C-14−N linkage.
Fistulain B has a new carbon skeleton with a C-14−C-5′ linkage
formed between two different chromone units. Fistulain A
displayed anti-TMV activity, and both 1 and 2 showed weak cytotoxicities