Studies on the constituents of Broussonetia species. II. Six new pyrrolidine alkaloids, broussonetine A, B, E, F and broussonetinine A and B, as inhibitors of glycosidases from Broussonetia kazinoki Sieb

Six new pyrrolidine Alkaloids called broussonetine A, B, E, F, and broussonetinine A and B were isolated from the branches of Broussonetia kazinoki Sieb. (Moraceae). Broussonetine A, B, E and F were formulated as 2 beta-hydroxymethyl-3 beta-hydroxy-5-alpha- (10-oxo-13-hydroxytridecyl)-pyrrolidine-4-O-beta-D-glucopyranoside (1), 2 beta-hydroxymethyl-3 beta-hydroxy-5 alpha-(9-oxo-13-hydroxytridecyl)-pyrrolidine-4-O-beta-D-glucopy ran oside (2), 2 beta-hydroxymethyl-3 alpha,4 beta-dihydroxy-5 alpha-(1,13-dihydroxy-10-oxo-tridecyl)-pyrrolidine (3), and 2 beta-hydroxymethyl-3 alpha,4 beta-dihydroxy-5 alpha-(1,13-dihydroxy-9-oxo-tridecyl)-pyrrolidine (4), respectively. Broussonetinine A and B (5 and 6) were also isolated and identified as the aglycones of 1 and 2. 3 and 4 exhibited a strong inhibition of alpha-glucosidase, beta-glucosidase, beta-galactosidase and beta-mannosidase, while 5 and 6 showed a strong inhibition of beta-galactosidase and alpha-mannosidase.