The genus Uncaria (Rubiaceae) comprises 34 species worldwide
with 11 of them endemic to China.1 The dried hooks of some
Uncaria species have been used as the well-known traditional
Chinese medicine “Gou-teng” to relieve hypertension, epilepsy,
preeclampsia, and associated symptoms such as headaches and
dizziness.2 These activities have been linked to the presence of
oxindole alkaloids.