Polyhydroxy alkaloid isolated from the seeds of the Australian leguminous tree, Castanospermum australe. Inhibits enzymatic glycoside hydrolysis. Isoln of the naturally occurring (+)-form: L. D. Hohenschutz et al., Phytochemistry 20, 811 (1981). Total synthesis and absolute configuration: R. C. Bernotas, B. Ganem, Tetrahedron Lett. 25, 165 (1984). Alternate synthesis: H. Hamana et al., J. Org. Chem. 52, 5492 (1987). Inhibition of α- and β-glucosidases: R. Saul et al., Arch. Biochem. Biophys. 221, 593 (1983); eidem, ibid. 230, 668 (1984). Insect antifeedant activity: D. L. Dreyer et al., J. Chem. Ecol. 11, 1045 (1985). Inhibition of HIV infectivity in vitro: B. D. Walker et al., Proc. Natl. Acad. Sci. USA 84, 8120 (1987); R. A. Gruters et al., Nature 330, 74 (1987).