Chemical constituents and antitubercular activity of Formosan Pisonia umbellifera.

Bioassay-guided fractionation of the methanolic extract of the stem of Pisonia umbellifera (Nyctaginaceae) afforded the three new compounds, secopisonic acid (1), 6,8-dimethylisogenistein (2), and (+)- ENT-ficusol (3), and four first isolates from nature, pisoninol I (4), pisoninol II (5), pisoquinoline (6), and pisodienone (7), together with fifteen known compounds. Their structures were elucidated by analysis of spectroscopic data. Seven of these isolates, 3, 7, 12, 16, 18, 20, and 21 showed antitubercular activities against Mycobacterium tuberculosis H37R (V) in vitro, with MIC values ≤ 50 µg/mL. © Georg Thieme Verlag KG Stuttgart · New York.