A new compound govaniadine (1), along with three known tetrahydroprotoberberine-type alkaloids caseadine (2), caseamine (3), and protopine (4), were isolated from the plant Corydalis govaniana Wall. All alkaloids 1-4 exhibited a good urease enzyme inhibition with IC50 +/- S. E. M. values of 20.2 +/- 3.6, 38.9 +/- 2.8, 66.7 +/- 1.2, and 54.1 +/- 1.2 mu M, respectively, which are comparable to the standard inhibitor, acetohydroxamic acid (IC50 = 42.0 mu M). None of these compounds showed inhibition against alpha-chymotrypsin. This is the first report of urease inhibiting tetrahydroprotoberberine-type alkaloids. (C) 2013 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.