Glucosidases catalyze the cleavage of individual glucosyl residues from various glycoconjugates, including complex carbohydrates and glycoproteins. Castanospermine is an inhibitor of both α- and β-glucosidases, inhibiting lysosomal and neutral α-glucosidases with Ki values of 0.1 and 10 μM, respectively, and lysosomal and cytosolic β-glucosidases with Ki values of 7 and 40 μM, respectively. It is effective both in vitro and in vivo. Through its effects on glucosidases, castanospermine blocks N-linked glycosylation during post-translational modification of proteins, affecting protein trafficking and cell functions that are dependent on glycosylation, including angiogenesis. Castanospermine also interferes with viral replication and infection that is dependent on glucosidase activity.
The seeds of Castanospermum australe yield this simple alkaloid. It forms colourless crystals
from EtOH and is dextrorotatory with a specific rotation of [α]D25 +79.7° (c 0.93, H20).
Castano spermine has been characterized as the crystalline methiodide, m.p. 11O-112°C.
Castanospermine is a plant alkaloid shown to be a potent inhibitor of lysosomal a-or beta- glucosidase. It also inhibits mammalian glucosidase 1 and beta-mannosidase from sweet almonds and fungal beta-xylosidase.
Castanospermine, is used as a glycosidase inhibitor and antiinflammatory agent.castanospermine is used to inhibit syncytium formation between HIV-infected and CD4-expressing cells and may also interfere with infectivity. It has also been demonstrated that this agent inhibits inflammation at the level of leukocyte extravasation in rat models of experimental adjuvant-induced arthritis and autoimmune encephalomyelitis. Castanospermine is an inhibitor of Glucosidase I, Maltase-glucoamylase, and MANBA. Potent inhibitor of α- and β-glucosidases, especially glucosidase l (required for glucoprotein processing by transfer of mannose and glucose from asparagine-linked lipids). Inhibits HIV syncytium formation and replication.
a-L-fucosidases inhibitor
ChEBI: Castanospermine is a tetrahydroxyindolizidine alkaloid that consists of octahydroindolizine having four hydroxy substituents located at positions 1, 6, 7 and 8 (the 1S,6S,7R,8R,8aR-diastereomer). It has a role as a metabolite, an anti-HIV-1 agent, an anti-inflammatory agent and an EC 3.2.1.* (glycosidase) inhibitor.
Potent inhibitor of α - and β -glucosidases, especially glucosidase l (required for glucoprotein processing by transfer of mannose and glucose from asparagine-linked lipids). Inhibits HIV syncytium formation and replication.
1) Saul et al. (1984), Studies on the mechanism of castanospermine inhibition of alpha- and beta-glucosidases; Arch. Biochem. Biophys, 230 668
2) Repp et al. (1985), The effects of processing inhibitors on N-linked oligosaccharides on the intracellular migration of glycoprotein E2 of mouse hepatitis virus and the maturation of coronavirus particles; J. Biol. Chem., 260 15873
3) Gruters et al. (1987), Interference with HIV-induced syncytium formation and viral infectivity by inhibitors of trimming glucosidase; Nature, 330 74
4) Franc et al. (1990), Effects of deoxymannojirimycin and castanospermine on the polarized secretion of thyroglobulin; Endocrinology, 126 1464
5) Pili et al. (1995), The alpha-glucosidase I inhibitor castanospermine alters endothelial cell glycosylation, prevents angiogenesis, and inhibits tumor growth; Mol. Cancer Res., 55 2920
6) Rhinehart et al. (1987), Castanospermine blocks the hyperglycemic response to carbohydrates in vivo: a result of intestinal disaccharidase inhibition; Life Sci., 41 2325
