Two new pyrrolidine alkaloids called broussonetines C and D were isolated from the branch of Broussonetia kazinoki SIEB. (Moraceae). Broussonetines C and D were formulated as (2R,3R,4R,5R)-2-hydroxymethyl-3,4dihydroxy-5-(10-oxo-13-hydroxytridecyl)pyrrolidine (1) and (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-(9-oxo-13-hydroxytridecyl)pyrrolidine (2), respectively, by spectroscopic and chemical methods. 1 and 2 showed an inhibition to β-galactosidase and β-mannosidase.