Two new pyrrolidinyl piperidine alkaloids called broussonetines I and J were isolated from the branches of Broussonetia kazinoki SIEB. (Moraceae). Broussonetines I and J were formulated as (2R)-2-{(1S,2S)-1,2-dihydroxy-8-[(2R,3R,4R,5R)-5-(2-hydroxymethyl-3,4-dihydroxypyrrolidinyl)]octyl}-1-acetylpiperidine (1) and (2R)-2-{(1S,2S)-1, 2-dihydroxy-8-[(2R,3R,4R,5R)-5-(2-hydroxymethyl-3,4-dihydroxy-1-acetylpyrrolidinyl)]octyl}-1-acetylpiperidine (2), respectively, by spectroscopic and chemical methods.