Neptunia oleracea

Neptunia oleracea

The water mimosa or sensitive neptunia (Neptunia oleracea Lour., 1790) is a herbaceous species belonging to the Fabaceae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Plantae,
Division Magnoliophyta,
Class Magnoliopsida,
Subclass Rosidae,
Fabales Order,
Family Fabaceae,
Subfamily Mimosoideae,
Mimoseae tribe,
Genus Neptunia,
Species N. oleracea.
The terms are synonymous:
– Mimosa natans L.f.;
– Mimosa prostrata Lam.;
– Mimosa aquatica Pers.;
– Mimosa lacustris Bonpl.;
– Desmanthus lacustris Willd.;
– Desmanthus natans Willd.;
– Neptunia natans Druce;
– Neptunia prostrata Baill.;
– Neptunia stolonifera Guill. & Perr.;
– Neptunia aquatica (Pers.).

Etymology –
The term Neptunia comes from the Latin Neptunus, Neptune, god of the sea in Latin mythology.
The specific epithet oleracea comes from the Latin from ólus óleris, vegetable, that is, used as a vegetable.

Geographic Distribution and Habitat –
Neptunia oleracea is a plant widespread in a vast area that includes America: Belize, Brazil, Cuba, Ecuador, El Salvador, Jamaica, Guatemala, Guyana, Honduras, Mexico, Puerto Rico, Dominican Republic and Suriname; Africa: Angola, Benin, Botswana, Cameroon, Gambia, Ghana, Kenya, Malawi, Mali, Mozambique, Namibia, Niger, Nigeria, Democratic Republic of Congo, Senegal, South Africa, Sudan, Tanzania, Togo, Uganda, Zambia and Zimbabwe; Asia: Cambodia, Philippines, India, Indonesia, Laos, Malaysia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand and Vietnam.
Its native habitat is unknown although some experts believe it is found in the area from Mexico to northern South America.
It grows in stagnant waters and slow-flowing rivers, up to about 300 m above sea level.

Description –
Neptunia oleracea is a perennial aquatic plant, which has creeping, generally floating stems, swollen with aerenchyma (tissue which, in addition to allowing flotation, facilitates the transport of oxygen to all parts of the plant, the loss of this tissue, for any cause, causes it to sink) and rooted at the nodes; these extend into the water from 90 to 150 cm. It also has a dense tap root, up to 150 cm long, and rarely branched stems.
If planted in open ground it can reach 180 cm in height.
The leaves are sensitive (they close when touched); they are pinnate, with 2 – 4 pairs of auricles; with rachis, including petiole, up to 13 cm long; the leaflets vary from 7 to 22 pairs, oblong in shape and 5 to 20 mm long and 1.5 to 4 mm wide.
The inflorescence is orbicular; the flowers are yellow, with peduncles 1.5 to 2.5 cm long; the calyx is 1 to 3 mm long; the corolla varies from 3 to 4 mm in length.
The fruits are flat pods 2.5 to 5.1 cm long by 2.5 to 3.8 cm wide.
Inside these there are 4 to 8 seeds, each seed measuring from 1.9 to 2.8 cm in length by 0.8 to 1 cm in width.

Cultivation –
Neptunia oleracea is a plant that grows spontaneously in humid areas, streams and stagnant rivers and is harvested for food or medicinal use.
It is an easy and fast growing plant in humid tropical and marginally subtropical climates, where it can withstand temperatures up to around 5 °C during dormancy. Under favorable conditions young shoots can elongate at a rate of 5 – 7 cm per day.
This species grows best in areas where annual daytime temperatures are between 25 and 35°C, but can tolerate 15-38°C.
It prefers an average annual rainfall between 1,500 and 2,000 mm, but tolerates 1,000 – 4,000 mm.
It prefers areas along the muddy edges of waters or in still or slow-flowing waters. The plant prefers 30 – 80 cm depth of slow moving water and a position in full sun.
From a pedological point of view it prefers a pH between 5 and 6.5, tolerating 4.5 – 7.
It is a perennial plant that is sometimes treated as an annual in cultivation. Its harvest period is 4 – 6 months.
Yields of 30,000 – 50,000 shoots per hectare have been reported for each harvest.
This species has a symbiotic relationship with some soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen.
It is cultivated, particularly in south-east Asia, sometimes as an annual, for the vegetative tips, leaves and young legumes.
The plant reproduces by seed, but more frequently and easily by portions of the stem.
In fact, cuttings can be obtained by simply detaching pieces of stem that have already rooted in water.

Customs and Traditions –
Neptunia oleracea is a plant known by various common names, among these we remember: floating sensitive plant, sensitive neptunia, sensitive water plant, water mimosa (English); panilajak (Bengali); kânhchhnaèt (Cambodian); neptunie potegère (French); lajjalu (Hindi); kangkong putri, keman ayer, keman gajah (Malay); anatsiriry (Malagasy); water carurù (Portuguese – Brazil); alambusa (Sanskrit); sensitiva de agua (Spanish); suntaikkirai (Tamil); nirutalavapu (telegu); phak krachet (Thai); rau nhút (Vietnamese).
The plant is cultivated, particularly in south-east Asia for its vegetative tips, leaves and young legumes, rich in proteins, minerals and vitamins, which are consumed raw or cooked.
Leaves and shoots taste similar to cabbage; the young ends of the stems and pods are edible and usually eaten raw as a vegetable in Vietnam, Thailand, Laos and Cambodia and cultivated much like rice. The young leaves, shoot tips and young pods are usually eaten raw or stir-fried and curried such as kaeng som.
All parts of the plant are used in traditional medicine, especially Indian, for various pathologies.
The juice of the stem and roots is used for medicinal purposes. The whole plant extract appears to have shown cytotoxic activity on neoplastic cell lines, just as the herb extract has shown hepatoprotective activity.
From an ecological point of view, this plant is widespread and abundant throughout its known range. Populations improve thanks to cultivation and in some areas it can be considered an invasive species. The plant is classified as “Least Concern” in the IUCN Red List of Threatened Species (2013).

Preparation Method –
Neptunia oleracea is a plant used for both food and medicinal purposes in many countries. It is a common ingredient in Thai cuisine, and the plant is grown in some tropical areas of Asia for its edible leaves and young shoots.
In edible use, the leaves and floating stems are used, both raw and cooked.
They are crunchy and juicy, they are used in salads, cooked like a potherb and used in sour vegetable salads.
The young pods are also eaten cooked.
Yam phak krachet is a Thai salad made from this plant.
We also make a Laotian-style green papaya salad (left) served with raw sprigs of N. oleracea.
In traditional medicine the root is used as an external remedy against necrosis of the bones of the nose and hard palate.
The root is used in the advanced stage of syphilis.
The juice of the stem is squeezed into the ear to cure earache.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/189830439/original.jpg

Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, they do not represent in any way a medical prescription; we therefore decline any responsibility for their use for healing, aesthetic or food purposes.