Moringa

Moringa is a small, fast-growing, semi-evergreen tree usually 10–12 m tall, with soft green young shoots, light brittle wood and an open crown. Its leaves are tripinnate, 30–60 cm long, with many small oval, grey-green leaflets 1–2 cm long. The fragrant, creamy-white, bisexual flowers are borne in axillary sprays. The fruit is a 20–45 cm long, stick-like capsule (hence “drumstick tree”) holding many round, brown seeds with three thin wings at the angles. The taproot is swollen and pungently odoured.

According to Kew's Plants of the World Online, moringa is native from NE Pakistan to NW India (the Himalayan foothills), in seasonally dry tropical climate. It has long been widely planted and naturalised throughout the tropics and subtropics — Southeast Asia, China, Africa, the Middle East, Latin America and the Caribbean — thanks to its rapid growth and drought tolerance. It needs full sun and well-drained soil, tolerates poor soils, but is sensitive to frost and waterlogging. Globally it is assessed as Least Concern on the IUCN Red List.

Moringa's most characteristic compounds are glucosinolates, notably glucomoringin; when the enzyme myrosinase cleaves it (as leaves are cut or chewed), it releases the active isothiocyanate moringin. The leaves are rich in flavonoids — quercetin (about 12–20 mg/100 g dry leaves), kaempferol, rutin — plus phenolic acids such as chlorogenic and gallic acid, carotenoids (β-carotene) and vitamin C. The seeds contain a fatty oil (ben oil) dominated by oleic acid, together with behenic acid, tocopherols and phytosterols; the seed protein fraction includes cationic proteins (MOCP) able to coagulate suspended particles. The roots and root bark contain characteristic, toxic alkaloids (spirochin, moringine).

Moringa's young leaves, pods, flowers and immature seeds are a food rich in vitamin A, C, calcium, iron and protein containing all essential amino acids, widely used to improve nutrition in the tropics. Ground seed is a natural coagulant that clarifies turbid water: cationic seed proteins neutralise the charge of clay particles and microbes, aiding settling and reducing pathogens — a mechanism described since the 1990s (Ndabigengesere et al., 1995; Ghebremichael et al., 2005). The seed oil (ben oil) is used for food, cosmetics and light industry. Preclinical studies show leaf extracts have antioxidant, anti-inflammatory, antihyperglycaemic and antimicrobial activity, but human clinical evidence remains limited (Stohs & Hartman, 2015).

The leaves and young pods are considered safe as food, but the roots and root bark contain spirochin and other alkaloids that can be toxic and must never be eaten; they were also used in traditional abortifacient remedies, so pregnant women should avoid them. Raw seeds contain antinutritional factors, and high, prolonged medicinal doses warrant caution because of reports of liver and kidney effects. On the IUCN Red List moringa is assessed as Least Concern globally and is not listed by CITES; it is widely cultivated and not threatened, although some wild populations in its native range may face habitat loss.