Picrasma is a genus of flowering plants in the family Simaroubaceae, placed in the order Sapindales, and described by the Dutch botanist Carl Ludwig Blume. The genus comprises six to nine species of shrubs and trees, native to temperate and tropical regions of Asia and tropical regions of the Americas. Individual trees can reach heights of up to 20–25 metres.
Like other members of Simaroubaceae, Picrasma species are characterised by intensely bitter wood and bark, produced by a class of compounds called quassinoids — among the bitterest naturally occurring substances known. The genus name itself reflects this quality (see etymology). The white to yellowish-white wood is soft, light, and loosely grained.
The best-known species is Picrasma excelsa (Jamaican Quassia), a deciduous tree of the Caribbean and Central and South America, long used in traditional and folk medicine. Its bark contains quassinoids (including quassin), alkaloids, the coumarin scopoletin, and vitamin B1, and has been used as a febrifuge, digestive stimulant, antiparasitic, and insecticide. Bark extracts are also used as a bittering agent in food and beverages. Picrasma quassioides, native to temperate East Asia, is similarly used in traditional Chinese and Japanese medicine.
Etymology
The genus name Picrasma derives from the Greek pikrasmos (πικρασμός), meaning "bitterness," a direct reference to the intensely bitter taste of the wood and bark — a hallmark chemical character shared across the family Simaroubaceae.
Distribution
Picrasma species are distributed across two broad geographic regions: temperate to tropical Asia (including China, Japan, Korea, the Himalayas, India, Sri Lanka, and Southeast Asia including Java) and tropical regions of the Americas (the Caribbean, Central America, and northern South America). Picrasma excelsa is native to the Caribbean islands and adjacent mainland Americas; Picrasma quassioides ranges from the Himalayas through China to Japan.
Cultural Uses
The bark and wood of Picrasma species have long been used in traditional medicine across their ranges. Picrasma excelsa (Jamaican Quassia) bark is used as a febrifuge, appetizer, digestive tonic, antimalarial, and antiparasitic. Externally, bark preparations serve as a louse treatment and insecticide effective against flies, red spider mites, aphids, and woolly aphids. Bark extract is also used commercially as a bittering flavoring in food and drinks. Picrasma quassioides is used in traditional East Asian medicine in similar ways — as a bitter digestive tonic and antiparasitic.
