7-hydroxy-3-(4-hydroxybenzyl)chroman and broussonin b: neurotrophic compounds, isolated from Anemarrhena asphodeloides BUNGE, function as proteasome inhibitors.

The extract of Anemarrhenae Rhizoma (rhizomes of Anemarrhena asphodeloides BUNGE) showed neurotrophic activity toward rat pheochromocytoma (PC-12) cells. Bioassay-guided purification afforded four compounds, 2,6,4'-trihydroxy-4-methoxybenzophenone (1), 7-hydroxy-3-(4-hydroxybenzyl)chroman (2), broussonin B (3), and cis-hinokiresinol (4). Compounds 1-3 induced neurite outgrowth in PC-12 cells at concentration of 50 microg/ml, while 4 was less active. In addition, compounds 2-4 showed moderate inhibitory activities against a chymotrypsin-like activity of the proteasome.