Zanthoxylum is a genus of about 250 species of deciduous and evergreen trees, shrubs and climbers in the family Rutaceae that are native to warm temperate and subtropical areas worldwide. It is the type genus of the tribe Zanthoxyleae in the subfamily Rutoideae. Several of the species have yellow heartwood, to which their generic name alludes. Several species are cultivated for their use as spices, notably including Sichuan pepper.
Scientists screened dozens of South African medicinal plants against prostate cancer cells and found that small knobwood contains a natural compound, chelerythrine, that kills cancer cells at very low doses. They also discovered that this compound quietly converts into a weaker form when processed with certain lab solvents, which may help explain inconsistencies in earlier studies on similar plant compounds.
