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 2β-hydroxymethyl-3β-hydroxy-5α-(10-oxo-13-hydroxytridecyl)-pyrrolidine-4-O-β-D-glucopyranoside (1), 2β-hydroxymethyl-3β-hydroxy-5α-(9-oxo-13-hydroxytridecyl)-pyrrolidine-4-O-β-D-glucopyranoside (2), 2β-hydroxymethyl-3α, 4β-dihydroxy-5α-(1, 13-dihydroxy-10-oxo-tridecyl)-pyrrolidine (3), and 2β-hydroxymethyl-3α, 4β-dihydroxy-5α-(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 α-glucosidase, β-glucosidase, β-galactosidase and β-mannosidase, while 5 and 6 showed a strong inhibition of β-galactosidase and α-mannosidase.