Phellodendron amurense Rupr. is a species of tree in the family Rutaceae, commonly called the Amur cork tree.  The Ainu people used this plant, called shikerebe-ni, as a painkiller. Native to eastern Asia; northern China, Manchuria, Korea, Ussuri, Amur, and Japan, the Amur cork tree is considered invasive in many parts of North America. The State of Massachusetts lists it as a noxious weed. Compounds in the leaves (quercetin, quercetin-3-O-beta-D-glucoside, quercetin-3-O-beta-D-galactoside and kaempferol-3-O-beta-D-glucoside) demonstrated significant free radical scavenging activity comparable to vitamin E. Phellodendron amurense Essential Oils: Fruits- Myrcene (62.3-70.3%) and beta-caryophyllene (6.8-10.5%); Leaf oil contained beta-elemol (18.5%) and (Z)-beta-ocimene (12.6%); Flower oil (Z)-beta -ocimene (9.5%), beta-elemol (9.4%), myrcene (7.8%) and nonacosane (7.7%); Amurensin, a tert-amyl alcohol derivative of kaempferol 7-O-glucoside, can be found in P. amurense.