The genus Zanthoxylum (family Rutaceae) contains a fascinating group of plants found around the world from the tropics to temperate zones. With over 200 species, ranging from small shrubs to large trees, Zanthoxylum spp. are characterized by sharp thorns on either the stem or leaves. Various Zanthoxylum spp. are well recognized as Asian spices, including Sichuan pepper or hua jiao in China, sansho in Japan and chopi and sancho in Korea (Austin and Felger 2008). In South and Southeast Asia, various parts of Zanthoxylum plants are used as a spice in stews, marinades and soups.
Recent literature shows that the anaesthetizing effect of alpha-hydroxysanshool, a compound produced by Zanthoxylum, has potential as a commercial product to reduce skin irritation. This same compound also induces the numbing sensation experienced by eating certain (central to western) Chinese cuisines containing Sichuan pepper. In South Asia and Africa, Zanthoxylum is used in traditional remedies for toothaches, malaria and diarrhoea. A scan of scholarly publications indicates that some scientists are also interested in investigating Zanthoxylum spp. as a source of medicinal compounds to be used against major diseases including malaria and diarrhoea.