Mucuna pruriens is a tropical legume known as velvet bean or cowitch and by other common names (see below), found in Africa, India and the Caribbean. The plant is infamous for its extreme itchiness produced on contact, particularly with the young foliage and the seed pods. It has value in agricultural and horticultural use and has a range of medicinal properties.
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 youngM.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 havetwo 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 many parts of the world Mucuna pruriens is used as an important forage, fallow and green manure crop. Since the plant is a legume, it fixes nitrogen and fertilizes soil.
M.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. M. pruriens silage contains 11-23% crude protein, 35-40% crude fiber, and the dried beans 20-35% crude protein.
M.pruriens is sometimes used as a coffee substitute called “Nescafe” (not to be confused with the commercial brand Nescafé). 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 phtochemical compounds such as levodopa, making the product more suitable for consumption. If consumed in large quantities as food, unprocessed M pruriens is toxic to non ruminant mammals including humans.
Traditionally, M. pruriens has been used as an effective aphrodisiac. It is still used to increase libido in both men and women due to its dopamine inducing properties and in Ayurvedic medicine it is said to increase sperm count. Dopamine has a profound influence on sexual function.