The horseradish tree (Moringa oleifera) belongs to the bennut family (Moringaceae).
The German name Meerrettichbaum (horseradish tree), like the English Horseradish Tree, is derived from the content of mustard oil glycosides, which cause the roots to smell pungently burning like horseradish. These were also "discovered" by the English as a substitute for horseradish during the colonial period in India.
The term behen nut derives from the fact that behen oil, a highly stable lubricating oil, was extracted from the seeds and was particularly sought after in the watch industry before it was displaced from the European market by the cheaper olive and palm oil.
The fast-growing, deciduous to semi-evergreen tree reaches over 8-10 m in height. The root is thickened like a turnip, the trunk is relatively short with a diameter of up to 25-45 cm. It can thicken like a bottle under certain cultivation conditions. It branches into many widely projecting thinner, somewhat pendulous branches. The trunk produces a gum similar to a traganth.
The alternate and stalked leaves are clustered at the tips of the twigs. They are spirally arranged, 20 to 60 cm long and two- to three-pinnate. The short-stalked, elliptical or ovate to obovate, with entire margins and rounded to indented leaflets are about 1 to 2.5 cm long and lighter underneath.
The inflorescences are formed as many-flowered panicles that are 10 to 25 cm long and arise from the leaf axils. The flowers are fragrant (similar to violets) and creamy white to yellowish in colour.
The ripe fruits are about 2 cm wide or narrow, ribbed, leathery and brown, elongated, many-seeded, pointed, beaked capsules with a length of 25 to 45 (to over 90) cm long, which is why the plant also bears the English name drumstick tree. They remain hanging on the tree for a long time and finally pop open with three flaps.
The dark brown seeds, up to 1-1.5 cm in size, are roundish to triangular and each has three papery wings, up to about 1-2 centimetres long.
Presence and location
The tree originally comes from the Himalayan region in northwest India, but now grows worldwide in the tropics and subtropics - especially in countries in Africa, Arabia, Southeast Asia and the Caribbean islands - and has been intensively cultivated for decades in southern India, which can also be observed - albeit very slowly - in East Africa. However, there the tree is preferably used as a natural remedy in a wide variety of applications.
The cultivation of Moringa is not only intended to provide profitable income as food and fodder, but also to counteract deforestation. In poor regions (e.g. Niger), Moringa is cultivated as a primary food source, as the plant is suitable for combating malnutrition in these regions.
In the old East African-English tradition, the tree is still often referred to as the "Newer deat", which mainly refers to its almost indestructible endurance in very hot and dry areas. The horseradish tree thrives in hot, semi-arid climates with average rainfall totals between 250 and 1500 mm/year, but also grows in areas (up to 1500 metres above sea level) with higher humidity and annual rainfall totals of up to 3000 mm - albeit more slowly there. Although the species prefers well-drained, slightly loamy sandy soils, it also grows quite persistently on heavy clay soils. It even tolerates light frosts for short periods, but if they last longer they damage the tuberous roots. Due to its hygroscopic properties caused by the fine leaves with their high sodium content, the tree is ideally suited to hot dry areas and fully sunny locations.
It is particularly important to note that the horseradish tree does not tolerate waterlogging (even for a short time) because this causes root damage and consequently slows down growth, which is disadvantageous from the point of view of commercial use of the tree.
Very young, unripe dark green fruits are used like green beans and eaten as a vegetable. They are widespread in South and Southeast Asia. In South India, for example, they are popular in a sauce called drumsticks. These fruits are often harvested about 40 days after flowering, as they form a woody skin during the ripening process.
The young leaves are eaten much less frequently as a vegetable because the effort required to harvest them is quite high. However, the juice of the leaves is widely used throughout India and regularly used as a supplementary drink or in juice dietetics, which is widespread throughout Asia, to prevent and combat malnutrition and its consequences. In Asia and Africa, this mainly concerns nutrition-related anaemia or diabetes (type 2). Juice diets are mainly used for children and older people whose bodies tolerate purely chemical substance treatments only poorly or not at all.
The leaves of the plant are also used as animal feed. When used as feed for cattle, it has been shown that under certain circumstances weight gain can be increased by 32 % and milk production by 43 to 65 %.
One of the most stable vegetable oils is pressed from the seeds, which has a very long shelf life and does not go rancid. The seeds contain about 40 % of their weight as oil.
Research has shown that the seeds can be used to treat drinking water. In the process, the seeds are freed from the wings, peeled and dried and then ground into powder. This is then added to water that has been taken from rivers, for example, and therefore still has a high proportion of suspended matter and bacteria. A barrel full of this turbid water can be completely clarified with 200 to 300 mg of the powder if it is stirred slowly and evenly for 15-20 minutes. In the process, the suspended matter and bacteria are flocculated by the seed powder and thus sink to the bottom. After detailed investigations, a harmful effect of the powder on humans or on river and farmed fish can be excluded. The water-soluble bark gum of the horseradish tree is also used as a disinfectant finish in India.
The horseradish tree is a good example of how a popular vegetable in Asia and Africa can be of high nutritional value. All parts of the plant, especially the beet roots, contain mustard oil glycosides, from which pungent benzyl mustard oil develops when processed. The bark of the roots contains toxic alkaloids, "spirochine" and "moringinine", which is why it must be removed before consumption.
The edible parts of the plant, especially the leaves, have a high protein content, are rich in vitamins (especially vitamins A and C) and minerals (calcium, magnesium, potassium, iron and sodium). 
The following table shows various ingredients of Moringa (based on 100 g edible portion). 
|Ingredientt||Moringa||Recommended daily requirement of an adult|
|Provitamin A/Carotine||6,780 mg||0.8-1 mg vitamin A-retinol(animal only) = 4.8-6 mg all-trans-β-carotene (vegetable) = 9.6-12 mg other provitamin A-carotenoids (vegetable)|
|Vitamin C||220 mg||80-100 mg|
|Calcium||440 mg||800-1000 mg|
|Potassium||259 mg||2000 mg|
|Protein/protein||6,7 g||0.8 g - body weight in kg (e.g. 0.8 - 75 = 60 g recommended daily intake)|
Due to the fast growth, the simple cultivation possibilities (the plant can easily be propagated vegetatively through cuttings) and the versatile usability of the horseradish tree and other Moringa species, numerous projects have been started in developing countries in the tropics and subtropics to produce and market vegetables, seed powder or other products.
In September 2014, the Food and Agriculture Organisation of the United Nations (FAO) selected Moringa oleifera as the traditional crop of the month. The FAO wants to highlight Moringa as an easy-to-grow, nutrient-rich crop that can contribute to agricultural incomes locally, regionally and internationally.
All plant parts of the horseradish tree are used in the local traditional medicine of India, Sri Lanka, Java and Africa. The sap is used to stabilise blood pressure. Leaves have an anti-inflammatory effect. The roots are used to cure rheumatic complaints.
The alkaloid spirochine and moringine contained in the root has a bactericidal effect, which is why its use as an antibiotic and in biological plant protection is now also being tested. The long immature seed capsules are also said to contain medicinal substances.
Cultivation in Cuba propagated by Fidel Castro
In June 2012, the Cuban revolutionary leader and former president Fidel Castro made the horseradish tree as well as the mulberry tree the subject of a "reflection" published in all Cuban media since his retirement from active politics. In his text of a few lines, he propagated the cultivation of the two tree species "on a large scale" and described the Moringa oleifera as an "inexhaustible source of meat, eggs and milk". On the one hand, the unusual nature and form of these and other recent comments by the former statesman triggered speculation about his state of mind. On the other hand, the horseradish tree had already been increasingly disseminated in Cuba with state support since a year or two before Castro's statement as a cheap source of raw materials for herbal medicine as well as for food supplements, and is now all the more regarded there as a source of agricultural hope since the recommendation from the highest authority. In October, Fidel Castro spoke out again with more detailed information on the horseradish tree. In the run-up to the half-yearly session of the Cuban parliament, the members of the Committee for Agriculture and Food dealt in detail with the results of the mass cultivation of the horseradish tree demanded by Castro in December 2012.