Common Name: Soap-Bark Tree

General Information

Quillaja saponaria is an evergreen tree that can grow up to 18.00 metres tall.
The plant is harvested from the wild for local use as a medicine and source of materials.
Quillaja saponaria has a very wide distribution, large population, is not currently experiencing any major threats and no significant future threats have been identified. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2018)[].

Known Hazards

The plant is toxic if taken internally, tending to dissolve the blood corpuscles[].
The bark, and possibly other parts of the plant, contains saponins[].
Although poisonous, saponins also have a range of medicinal applications and many saponin-rich plants are used in herbalism (particularly as emetics, expectorants and febrifuges) or as sources of raw materials for the pharmaceutical industry. Saponins are also found in a number of common foods, such as many beans.
Saponins have a quite bitter flavour and are in general poorly absorbed by the human body, so most pass through without harm. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins.
Saponins are much more toxic to many cold-blooded creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish and make them easy to catch[].

Botanical References

Range

S. America - central Chile

Habitat

Mountainous regions on the western slopes of the Andes[, ].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	18.00 m
Growth Rate	Slow
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Quillaja saponaria is a moderately cold-tolerant plant, being known to withstand temperatures falling to about -12°c in its natural range in South America, where the heat of the summer ensures the wood ripens fully[]. They can succeed outdoors in the milder areas of this country, often as small shrubs but making a tree in the very mildest areas[].
Requires a well-drained fertile soil in a sunny position[].
The young growth in spring can be damaged by late frosts, so it is best to site the plant in a position sheltered from the early morning sun.
This species is cultivated for the saponins in its bark in some warm temperate areas of the world[].

Edible Uses

None known

Medicinal

Soap bark tree has a long history of medicinal use with the Andean people who used it especially as a treatment for various chest problems[]. The saponin content of the bark helps to stimulate the production of a more fluid mucous in the airways, thus facilitating the removal of phlegm through coughing[]. The tree is useful for treating any condition featuring congested catarrh within the chest, but it should not be used for dry irritable coughs[].
The inner bark contains about 9% of complex saponins, known collectively as 'quillajasaponin'[]. It also contains calcium oxalate and tannin[]. It has been used internally as a stimulating expectorant, though it can cause irritation and inflammation of the digestive tract and so is no longer considered safe[, ]. The internal use of this plant needs to be carefully overseen by a professional practitioner[]. Sap bark tree is used as a source of compounds for the pharmaceutical industry[]. It is still used externally as a cutaneous stimulant in the treatment of skin ulcers and eruptions, dandruff etc[, ].

Other Uses

The fresh or dried inner bark is a soap substitute[, , ]. It contains about 9% saponins and is a very gentle and effective cleaner[, ]. It is used for cleaning textiles and the skin[, , , ]. It can also be used as a hair tonic[, ]. The saponins are also used in anti-dandruff shampoos and exfoliant cleansers[]. They are used as a foaming agent in fire extinguishers[].
The bark also contains considerable quantities of carbonate of lime[].

Propagation

Seed - sow spring in a greenhouse. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for at least their first winter. Plant out in early summer and give some protection from the cold for at least their first winter outdoors.
Cuttings of fully ripe wood of the current year's growth, late autumn in a frame[].