Broussonins A and B, new phytoalexins from diseased paper mulberry. Broussonin B can induce neurite outgrowth in PC-12 cells at concentration of 50 microg/ml, and show moderate inhibitory activities against a chymotrypsin-like activity of the proteasome.Broussonin B also can significantly inhibit adipocyte differentiation in 3T3-L1 cells as measured fat accumulation using Oil Red O assay.