Evodia

Tetradium ruticarpum is a tree from China and Korea, formerly placed in the genus Euodia as Euodia ruticarpa. Its fruit is the part usually used, and it has a strong bitter taste. It is used in traditional Chinese medicine and is a recognised herb in Kampo, the Japanese system of herbal medicine, where it is called goshuyu. Goshuyu gives its name to the Kampo preparation goshuyu-tou and is also an ingredient of unkeito. Both the former genus name and the species name are often misspelled, and the plant usually appears in sources on traditional Chinese medicine as Evodia rutaecarpa, so a search by that spelling may find the same plant. The compound evodiamine, named after the former genus, has been reported from it. The Wikipedia page notes that there has been relatively little scientific study of the species.