Indolizidine alkaloids

Swainsonine is an indolizidine alkaloid. It is a potent inhibitor of Golgi alpha-mannosidase II, an immunomodulator, and a potential chemotherapy drug. As a toxin in locoweed (likely its primary toxin) it also is a significant cause of economic losses in livestock industries, particularly in North America. It was first isolated from Swainsona canescens.

Castanospermine is an indolizidine alkaloid first isolated from the seeds of Castanospermum australe. It is a potent inhibitor of some glucosidase enzymes and has antiviral activity in vitro and in mouse models.

thumb|220px|Pumiliotoxin A: R = –HPumiliotoxin B: R = –OH Pumiliotoxins (PTXs), are one of several toxins found in the skin of poison dart frogs. The frog species, P. bibronii also produces PTXs to deter predators. Closely related, though more toxic, are allopumiliotoxins, (aPTXs). Other toxins found in the skin of poison frogs include decahydroquinolines (DHQs), izidines, coccinellines, and spiropyrrolizidine alkaloids. Pumiliotoxins are poisonous in high concentrations. Pumiliotoxins are much weaker than batrachotoxins, ranging between 100 and 1000 times less poisonous.

Securinine is an alkaloid found in Securinega suffruticosa and Phyllanthus niruri.