Common Name: Horse Chestnut

General Information

Aesculus hippocastanum is a deciduous tree with an upright, oval-rounded crown; it can grow 15 - 25 metres tall[].
The tree is a well-known and effective medicinal herb, often harvested from wild and cultivated trees. It is also occasionally used as a food and source of materials. A very ornamental and fast-growing tree, it is much grown as an avenue tree and in larger areas such as parks and large gardens[, ]
Although a common tree in cultivation, the plant is declining very significantly in the wild due to a range of threats The plant is classified as 'Near Threatened' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The plant is poisonous, containing the glycoside aesculin, the saponin aescin, and possibly alkaloids. The symptoms include muscle weakness and paralysis, dilated pupils, vomiting, diarrhea, depression, paralysis, and stupor - death has been known to result[].
The seed is rich in 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

Southeastern Europe - Greece, Albania, Macedonia, Bulgaria.

Habitat

Mountain woods[].

Properties

Conservation Status	Near Threatened
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	30.00 m
Growth Rate	Fast
Pollinators	Bees
Cultivation Status	Ornamental, Wild

Cultivation Details

Aesculus hippocastanum is a hardy and very tolerant tree. It grows best in more continental climates with their clearer demarcation between winter and spring, though they can also succeed in more maritime climates. Trees are very hardy when dormant, but the young growth in spring can be damaged by late frosts.
Succeeds in full sun to partial shade[]. Prefers a deep, loamy, moist but well-drained soil but is not too fussy tolerating poorer drier soils[, ]. Tolerates exposed positions and atmospheric pollution[].
The flowers have a delicate honey-like perfume[].
Trees are tolerant of drastic cutting back and can be severely lopped[]. They are prone to suddenly losing old heavy branches[].
The tree comes into bearing within 20 years from seed[].
Seedlings quickly develop a taproot and larger plants can be difficult to transplant[].

Edible Uses

The roasted seed is used as a coffee substitute[, ].

Seed - cooked. It can be dried, ground into a powder and used as a gruel[, , , ]. The seed is quite large, about 3cm in diameter, and is easily harvested. It is usually produced in abundance in Britain. Unfortunately the seed is also rich in saponins, these must be removed before it can be used as a food and this process also removes many of the minerals and vitamins, leaving behind mainly starch. See also the notes above on toxicity. The seed contains up to 40% water, 8 - 11% protein and 8 - 26% toxic saponins[].
The following notes apply to Aesculus californica, but are probably also relevant here:-
The seed needs to be leached of toxins before it becomes safe to eat - the native North Americans would do this by slow-roasting the nuts (which would have rendered the saponins harmless) and then cutting them into thin slices, putting them into a cloth bag and rinsing them in a stream for 2 - 5 days[]. Most of the minerals etc would also have been leached out by this treatment[].

Medicinal

Horse chestnut is an astringent, anti-inflammatory herb that helps to tone the vein walls which, when slack or distended, may become varicose, haemorrhoidal or otherwise problematic[]. The plant also reduces fluid retention by increasing the permeability of the capillaries and allowing the re-absorption of excess fluid back into the circulatory system[]. This plant is potentially toxic if ingested and should not be used internally without professional supervision[].
Alterative, analgesic, haemostatic and vulnerary[, ].

The bark is anti-inflammatory, astringent, diuretic, febrifuge, narcotic, tonic and vasoconstrictive[, , ]. It is harvested in the spring and dried for later use[]. The plant is taken in small doses internally for the treatment of a wide range of venous diseases, including hardening of the arteries, varicose veins, phlebitis, leg ulcers, haemorrhoids and frostbite[, ]. It is also made into a lotion or gel for external application[]. A tea made from the bark is used in the treatment of malaria and dysentery, externally in the treatment of lupus and skin ulcers[, ].
A tea made from the leaves is tonic and is used in the treatment of fevers and whooping cough[, , ].

The pericarp is peripherally vasoconstrictive[].

The seeds are decongestant, expectorant and tonic[, ]. They have been used in the treatment of rheumatism, neuralgia and haemorrhoids[]. They are said to be narcotic and that 10 grains of the nut are equal to 3 grains of opium[].

An oil extracted from the seeds has been used externally as a treatment for rheumatism[].

A compound of the powdered roots is analgesic and has been used to treat chest pains[].

The buds are used in Bach flower remedies - the keywords for prescribing it are 'Failure to learn by experience', 'Lack of observation in the lessons of life' and hence 'The need of repetition'[].
The flowers are used in Bach flower remedies - the keywords for prescribing it are 'Persistent unwanted thoughts' and 'Mental arguments and conversations'[].

Other Uses

Saponins in the seed are used as a soap substitute[]. The saponins can be easily obtained by chopping the seed into small pieces and infusing them in hot water. This water can then be used for washing the body, clothes etc. Its main drawback is a lingering odour of horse chestnuts[]. The seed contains variable amounts of saponins, up to a maximum of 10%[].

A starch obtained from the seed is used in laundering[].

The bark and other parts of the plant contain tannin, but the quantities are not given[].

A yellow dye is obtained from the bark[].
The flowers contain the dyestuff quercetin[].

Wood - soft, light, not durable. Of little commercial value, it is used for furniture, boxes, charcoal[, , , ].

Propagation

Seed - best sown outdoors or in a cold frame as soon as it is ripe[, ]. The seed germinates almost immediately and must be given protection from severe weather[]. Seedlings develop a large taproot following germination and so, if grown in containers, should be given sufficient root room[]. The seed has a very limited viability and must not be allowed to dry out. Stored seed should be soaked for 24 hours prior to sowing and even after this may still not be viable[, ]. It is best to sow the seed with its 'scar' downwards[]. If sowing the seed in a cold frame, pot up the seedlings in early spring and plant them out into their permanent positions in the summer.