Classification

Moringa oleifera Lam., drumstick tree or horseradish tree, belongs to the order Brassicales and is a member of the Moringaceae.

Fig: Photos of Moringa oleifera and its different plant parts 1: whole plant; 2: leaves; 3: flowers; 4: pods; 5: seeds; 6: root. (Source: Philipp Schiecke, MSc thesis, LUH, 2020)

Structure

Moringa oleifera is a very fast-growing, deciduous tree, which usually reaches a height of 10-15 m. Already in the first year it can exceed a height of 3 m, often the growth is up to 7 m in one year. It has bulbous roots, corky white bark and spongy soft wood. The thin, widely spreading leaflets are tripinnate and 20-50 cm long. The fruits or pods are pendulous and long, tapering on either side. They are drumstick shaped, which is why the plant is also called drumstick tree. They contain about 20-35 seeds. The seeds are dark brown and have three papery wings. The flowers have five sepals, five petals and five stamens. They are zygomorphic. The tree is diploid with 2n = 28.

Fig: Distribution of Moringa oleifera worldwide. Green: Native; purple: Introduced (Source: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:584736-1)

Spatial distribution

Moringa oleifera is a fast-growing, drought-tolerant tree species native to the Indian subcontinent but now cultivated in many tropical and subtropical regions all over the world. It flowers already 6 months after planting. It originates from the west of the Himalayas and the east of Punjab and was then first cultivated in India. From there it has spread to very many tropical and subtropical countries. However, it has also been used by other peoples, such as the Romans, Greeks, and Egyptians in ancient times.

Cultivation

The moringa tree is grown mainly in semiarid, tropical and subtropical areas. It tolerates a wide range of soil conditions but prefers a neutral to slightly acidic (pH 6.3 to 7.0), well-drained, sandy or loamy soil. The drought-tolerant and disease-resistant tree grows in areas with an annual rainfall of 250 to 1500 mm. It can survive in both humid tropics and arid countries and can cope with nutrient-poor soil. The tree grows naturally at altitudes of up to 1000 m above sea level. It is mainly cultivated in India. Traditionally, Moringa oleifera is propagated almost exclusively by seed in some regions (Sudan), but by vegetative methods in others (India).

Nutritional value

The tropical tree Moringa oleifera contains many valuable nutrients as well as secondary phytonutrients and is therefore highly estimated. Because of its nutritionally and health relevant properties and its common availability it is utilized by many people especially in the tropical countries as a high-quality food source. These days M. oleifera is frequently used world-wide as a nutritional supplement being considered as “superfood“. Many medical effects have been investigated in studies. Moringa oleifera contains partly unique glucosinolates and alkaloids with specific effects. Especially the leaves of this tree species are consumed and employed all over the world for nutrition and health care. Whereas their high nutritional value is particularly attributed to the tremendous high protein content, the reports on the health beneficial effects are primarily based on the exceptional glucosinolates which are present in high concentrations in M. oleifera leaves as well as on various antioxidants, vitamins and minerals. Glucosinolates are present at all developmental stages and in all organs.

Special features

Up to now, the nutritional properties had been attributed primarily to the putatively high protein content of Moringa oleifera leaves. However, it was shown that the protein content of Moringa oleifera leaves is not exceptional and is in the same range as found for leaves of other plant species. Moreover, also the amino acids composition of Moringa oleifera leaves is not that exceptional as commonly mentioned (DOI: https://doi.org/10.5073/JABFQ.2020.093.032). Thus, the high number of positive effects described in the literature must have another origin, which needs to be elucidated. The plant family Moringaceae contains only one genus Moringa and 13 species. Both shrubs and trees occur in the monogeneric genus. It is characterized by a great diversity of habitats and morphological appearances. For its size, it is one of the genera most phenotypically distinct among all angiosperms. Plants from the genus Moringa can be divided into three groups. One is slender trees (M. oleifera, M. concanensis, M. peregrina), bottle trees (M. drouhardii, M. hildebrandtii, M. stenopetala, M. ovalifolia), and tuberous trees and shrubs from northern and eastern Africa (M. longituba, M. ruspoliana, M. borziana, M. pygmaea, M. arborea, M. rivae). Moringa oleifera is the plant from the genus Moringa that is best known and most widely cultivated. It is a very diverse plant that is very popular and well known in the areas where it is cultivated. It has different and sometimes very descriptive names in many countries, often referring to the appearance or the field of application.