Velvet bean

Mucuna pruriens (syn. Dolichos pruriens) is a tropical legume known by a multitude of common names (see below).

Common names

Description

The plant is an annual, climbing shrub with long vines that can reach over 15 m in length. When the plant is young, it is almost completely covered with fuzzy hairs, but when older, it is almost completely free of hairs. The leaves are tripinnate, ovate, reverse ovate, rhombus shaped or widely ovate. The sides of the leaves are often heavily grooved and the tips are pointy. In young Mucuna pruriens plants, both sides of the leaves have hairs. The stems of the leaflets are two to three millimeters long. Additional adjacent leaves are present and are about 5 mm long.

The flower heads take the form of axially arrayed panicles. They are 15 to 32 cm long and have two to three, or many flowers. The accompanying leaves are about 12.5 mm long, the flower stand axes are from 2.5 to 5 mm. The bell is 7.5 to 9 mm long and silky. The sepals are longer or of the same length as the shuttles. The crown is purplish or white. The flag is 1.5 mm long. The wings are 2.5 to 3.8 cm long.

In the fruit ripening stage, a 4 to 13 cm long, 1 to 2 cm wide, unwinged leguminous fruit develops. There is a ridge along the length of the fruit. The husk is very hairy and carries up to seven seeds. The seeds are flattened uniform ellipsoid, 1 to 1.9 cm long, 0.8 to 1.3 cm wide and 4 to 6.5 cm thick. The hilum, the base of the funiculus (connection between placenta and plant seeds) is a surrounded by a significant arillus (fleshy seeds shell).

Mucuna pruriens bears white, lavender, or purple flowers. Its seed pods are about 10 cm long^[1] and are covered in loose orange hairs that cause a severe itch if they come in contact with skin. The chemical compounds responsible for the itch are a protein, mucunain,^[1] and serotonin. The seeds are shiny black or brown drift seeds. It is found in tropical Africa, India and the Caribbean.

Uses

In many parts of the world Mucuna pruriens is used as an important forage, fallow and green manure crop.^[3] Since the plant is in the legume family (peas and beans), it, with the help of nitrogen fixing bacteria, takes nitrogen gas from the air and combines it with other chemical compounds producing fertilizer and improving the soil.

Mucuna pruriens is a widespread fodder plant in the tropics. To that end, the whole plant is fed to animals as silage, dried hay or dried seeds. Mucuna pruriens silage contains 11-23% crude protein, 35-40% crude fiber, and the dried beans 20-35% crude protein..

Mucuna pruriens is sometimes used as a coffee substitute called "Nescafe" (not to be confused with the commercial brand). Cooked fresh shoots or beans can also be eaten. This requires that they be soaked from at least 30 minutes to 48 hours in advance of cooking, or the water changed up to several times during cooking, since otherwise the plant can be toxic to humans. The above described process leaches out chemical compounds such as levodopa, making the product suitable for consumption. If consumed as food, unprocessed Mucuna pruriens is toxic to nonruminant animals including humans.

In history, M. pruriens has been used as an aphrodisiac^[4] (hence the species name, pruriens, i.e., prurience/prurient). It is still used to increase libido in both men and women due to its dopamine inducing properties. Dopamine has a profound influence on sexual function.^[5]^[6] A typical dose for a man is 15 g of ground seeds mixed with cow's milk.^[1]

Mucuna pruriens seeds have also been found to have antidepressant properties when consumed.^[7]

Mucuna pruriens has also recently become popular among lucid dreaming enthusiasts: when combined with other supplements that stimulate the cholinergic system, the dopamine presumably produced from the consumption of Mucuna pruriens confers upon the lucid dreamer greater motivation and confidence.

The hairs lining the seed pods contain 5-hydroxytryptamine (serotonin) which causes severe itching (erythema).^[8]^[9] The hairs on the outside of the pods of Mucuna pruriens are a common ingredient in itching powder.^[10]

Mucuna pruriens is used in the countries of Benin and Vietnam as a biological control for problematic Imperata cylindrica grass.^[3] Mucuna pruriens is said not to be invasive outside its cultivated area.^[3]

Pharmacology

Mucuna pruriens seeds contain high concentrations of levodopa, a direct precursor of the neurotransmitter dopamine. It has long been used in traditional Ayurvedic Indian medicine for diseases including Parkinson's Disease.^[11]^[12] In large amounts (e.g. 30 g dose) it has been shown to be as effective as as pure levodopa/carbidopa in the treatment of Parkinson's Disease, but no data on long-term efficacy and tolerability is available.^[13]

The mature seeds of the plant contain about 3.1-6.1% L-DOPA,^[8] also trace amounts of bufotenine, DMT, DMT-n-oxide, 5-MeO-DMT-n-oxide, beta-carboline, nicotine and 5-hydroxytryptamine.^[15] One study using 36 samples of the seeds found no tryptamines present in them.^[16]

The leaves contain about 0.5% L-DOPA, 0.006% dimethyltryptamine (DMT), 0.0025% 5-MeO-DMT and 0.003% DMT n-oxide.^[17]

Subspecies and varieties

Subspecies^[1]

Varieties

Contents

Common names

Description

Uses

Pharmacology

Subspecies and varieties

Subspecies^[1]

Varieties

See also

External links

References

Contents

Common names

Description

Uses

Pharmacology

Subspecies and varieties

Subspecies[1]

Varieties

See also

External links

References

Subspecies^[1]