Mucuna Pruriens "Velvet Beans"

Botany

Mucuna pruriens (L.) DC. — basionym Dolichos pruriens L. — is a vigorous climbing legume of the Fabaceae family, with violet flower clusters. The genus Mucuna holds about 150 species. Her pods, 8 to 10 cm long, are covered in fine stinging hairs (trichomes) that contain mucunain, a protease, and serotonin, which cause intense itching on contact. The English names cowhage and cowitch come from the Hindi kevā̃c. Inside lie large, flat, dark-brown seeds, the part that is used. Her exact geographic origin is lost (probably tropical Asia); the plant now grows across the tropics of both hemispheres. (Rätsch, The Encyclopedia of Psychoactive Plants, pp. 370-371.)

Names as functions

Kapikacchu — "monkey itch" — points to the stinging pod: the seed is reached only by respecting its hairs. Atmagupta — atma, the self, and gupta, hidden or protected — names the treasured seed kept inside a hostile pod, like the self beneath its defences. Markati, "like a monkey". In English velvet bean, for the down on the young pods; in Spanish ojo de venado, "deer's eye". And fearful names in the places that met the plant without knowing it: mad beans in Mozambique, devil beans in Nigeria, voodoo beans in the United States.

Phytochemistry (descriptive)

The signature compound is L-DOPA (levodopa), typically 3 to 6% of the seed's dry weight. L-DOPA is the amino acid that is the direct precursor of dopamine, and it crosses the blood-brain barrier, which dopamine itself cannot do. The seed also contains, in minor amounts, serotonin, 5-HTP (the precursor of serotonin), beta-carbolines (weak MAO inhibitors) and traces of other indole alkaloids, whose profile varies with variety and region.

Variability and the whole-seed choice

An important point: the actual L-DOPA content varies widely from one variety, soil and preparation to another. That is why INFUSE chose the whole seed as a powder, the traditional form, over an extract standardised to a fixed percentage: in the whole seed, L-DOPA stays with the rest of the seed's compounds. The amount of L-DOPA per spoonful therefore varies, and this plant-food is taken in modest amounts and in cycles.

Roasting and heat

L-DOPA is sensitive to heat: prolonged boiling can destroy a large part of it (sources report up to about 70%). Traditional preparation therefore favours gentle dry roasting, as for coffee, or stirring the powder into a drink that is hot but off the boil. This is the logic of the Mesoamerican "nescafé": roasted, ground seeds infused in hot water, giving a coffee-like drink without caffeine.

Long history and gems

Beyond India and Mesoamerica, mucuna is grown in Africa (Mozambique, Nigeria, Guinea) as a nitrogen-fixing cover crop, and eaten as a pulse after proper preparation. In 1985, in Paterson, New Jersey, an outbreak of itching that residents blamed on "voodoo beans" was traced to Mucuna pruriens (CDC, MMWR).

Safety

Only the inner seeds, shelled and cleared of their hairs, are eaten. Because of the L-DOPA, the contraindications are serious (see Precautions): interactions with MAOIs, antipsychotics and dopaminergic treatments; avoid during pregnancy and breastfeeding, and in case of psychosis, mania, malignant melanoma, phenylketonuria, hyperthyroidism, arrhythmia or angina (Pierre & Gayet, La Bible de l'herboristerie, pp. 604-606). Always take it in cycles, which respects the regulation of the dopamine receptors. In case of doubt or ongoing treatment, a health professional's advice comes first.