Horse Chestnut, European Horsechestnut, Common Horsechestnut

Aesculus hippocastanum

Physical Characteristics

Aesculus hippocastanum is a deciduous Tree growing to 30 m (98ft) by 15 m (49ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 3 and is not frost tender. It is in flower in May, and the seeds ripen in September. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil. The plant can tolerates strong winds but not maritime exposure. It can tolerate atmospheric pollution.

Distribution

Europe - N. Greece and Albania. Naturalized in Britain[17].

Habitats

Woodland Garden Canopy;

Edible Uses

Edible Parts: Seed Edible Uses: Coffee The roasted seed is used as a coffee substitute[2, 7]. Seed - cooked. It can be dried, ground into a powder and used as a gruel[7, 46, 55, 61]. 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[218]. The following notes apply to A. californica, but are probably also relevant here:- The seed needs to be leached of toxins before it becomes safe to eat - the Indians 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[213].

Medicinal Uses

Alterative Analgesic Antiinflammatory Antirheumatic Astringent Bach Diuretic Dysentery Expectorant Febrifuge Haemostatic Malaria Narcotic Tonic Vasoconstrictor Vulnerary 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[254]. 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[254]. This plant is potentially toxic if ingested and should not be used internally without professional supervision[254]. Alterative, analgesic, haemostatic and vulnerary[165, 218]. The bark is anti-inflammatory, astringent, diuretic, febrifuge, narcotic, tonic and vasoconstrictive[4, 7, 222]. It is harvested in the spring and dried for later use[4]. 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[238, 254]. It is also made into a lotion or gel for external application[254]. A tea made from the bark is used in the treatment of malaria and dysentery, externally in the treatment of lupus and skin ulcers[4, 222]. A tea made from the leaves is tonic and is used in the treatment of fevers and whooping cough[222, 240, 254]. The pericarp is peripherally vasoconstrictive[7]. The seeds are decongestant, expectorant and tonic[7, 21]. They have been used in the treatment of rheumatism, neuralgia and haemorrhoids[4]. They are said to be narcotic and that 10 grains of the nut are equal to 3 grains of opium[213]. An oil extracted from the seeds has been used externally as a treatment for rheumatism[254]. A compound of the powdered roots is analgesic and has been used to treat chest pains[257]. 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'[209]. The flowers are used in Bach flower remedies - the keywords for prescribing it are 'Persistent unwanted thoughts' and 'Mental arguments and conversations'[209]. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Aesculus hippocastanum for chronic venous insufficiency in the legs (see [302] for critics of commission E).

Known Hazards

The seed is rich in saponins[10, 21, 65]. Although poisonous, saponins are poorly absorbed by the human body and so most pass through without harm. Saponins are quite bitter and can be found in many common foods such as some beans. They can be removed by carefully leaching the seed or flour 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 food that contain saponins. Saponins are much more toxic to some 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[K]. Avoid in patients with kidney or liver disease. Avoid if taking warfarin as can interfere with anticoagulant therapy [301].