Pau D'arco is a tree native to South America, preparations derived from the bark of which have been traditionally used to treat bacterial, fungal, viral infections, and cancer. Quinones, the main constituents, were shown to be the active principle of Pau D'arco (11) (12) (13) (14).
In vitro and in vivo studies of compounds isolated from Pau D'arco demonstrated antibacterial (3) (4) (5) (6), antifungal (7), antipsoriatic (8), immunomodulatory (9) (10), anti-inflammatory (19), antidepressant (20), anticancer (11) (12) (13) (14), and antimetastatic (14) properties. One of the compounds may also be effective against inflammatory disorders (24). A Pau D'arco extract selectively inhibits growth of ER positive breast cancer cells (21). Human studies are needed to validate these effects.
In a small single-arm study, Lapachol, a naphthoquinone isolated from the tree bark, failed to show any effects on patients with non-leukemic tumors or CML (chronic myelocytic leukemia) (15).
Reported adverse events from use of Pau D'arco include nausea, vomiting, dizziness and anemia (16). It may also enhance the activity of anticoagulants (17).