Swainsonine is an indolizidine alkaloid naturally found in certain plants including locoweed that inhibits N-linked glycoside hydrolases, preventing the processing of asparagine-linked glycoproteins. It reversibly inhibits lysosomal α-mannosidase and Golgi α-mannosidase II (IC50 = 0.2 μM). Swainsonine is used to study the role of N-linked glycosylation in cellular processes and has been shown to have antiproliferative and antimetastatic effects of cancer cells in culture and in mice. The inhibition of α-mannosidase activity in lysosomes produces an accumulation of partially-processed oligosaccharides and glycoproteins, giving rise to lysosomal storage disease. Swainsonine toxicity in herbivores results in a condition known as locoism, characterized by hyperactivity, aggression, stiff and clumsy gait, low head carriage, salivation, seizures, and apparent blindness, culminating in increased miscoordination, weakness and death.
