English: Cowhage, cowitch,
Hindi: Kavach,
Sanskrit: Atmagupta, vanari

The use of this species as an anthelmintic was first recorded by Patrick Browne in his Civil and Natural History of Jamaica, 1756, and it has also been mentioned in other books on traditional medicine. Ancient Sanskrit texts indicate that it was used as an aphrodisiac and its use in a formulation for tremors is recorded. L-dopa, the major constituent of the seeds, revolutionised the treatment of Parkinson's disease in the 1960s. The seeds have been used as promoters of virility.

Habitat

Originally from India, it is widely grown in the tropics as a fodder crop and naturalised in many other countries including Sri Lanka, south -east Asia and Malaysia.

Botanical description

A tender, evergreen, twining climber, reaching 3 m, with downy leaves up to 45 cm long, divided into three ovate, pointed leaflets (Plate 38). Clusters of purple or white, pea-like flowers, about 5 cm long, appear in summer, followed by flattened pods, up to 9 em long and 2 cm wide, with a pointed, often hooked, apex. The pods contain 3-6 seeds, about 1 cm long, and are covered in orange or dark brown, irritant bristles.

Parts used

Seeds, root, legumes.

Traditional and modern use

The traditional use centres mainly on its use as an anti parkinsonian agent, anthelmintic and aphrodisiac. A hot water extract of the dried fruit is administered to children in cases of intestinal worms and the powdered trichomes of the pod have been taken orally for this purpose, along with milk or buttermilk. However, this can be dangerous and should be avoided. A water extract of leaves is used as an aphrodisiac, nerve tonic, for scorpion stings and in dysentery. The seeds are taken orally by men to cure night dreams and impotency, to promote fertility and as an aphrodisiac to increase seminal fluid and vigour. In this case, two seeds are powdered and taken with a cup of cow's milk. A powdered seed, taken with milk, is also used for diarrhoea. Hot water extracts of the dried seeds are taken orally as a nervine and to procure abortion. The dried powdered root has been taken with honey as a blood purifier, diuretic and to dissolve kidney stones and for persistent coughs, the seeds are sometimes placed over a hot plate or burning charcoal and the fumes inhaled through the mouth. Several of these effects have been substantiated by recent scientific investigations.

Ethnoveterinary usage

It is used in urinary complaints, for elephantiasis, snake bite, anthrax, tympanitis and lumbar fracture.

Major chemical constituents
Alkaloids

Prurienene, prurieninine, prurienidine, mucunine, mucunadine, mucuadine, mucuadinine, mucuadininine and nicotine are reported in the whole plant.

Triterpenes and sterols

ß-Sitosterol, stigmasterol, ß-amyrin acetate, ursolic acid and betulinic acid are present in the root.

Proteins and amino acids

L-dopa, methionine, phenylalanine, tyrosine, lysine, aspartic acid, glutamic acids, glycine, leucine, isoleucine, and serine, together with globulins and albumins, have been isolated from the seed.

Fatty acids1 carbohydrates and related compounds

Oleic acid, linoleic acid, palmitic acid, lecithin, lauric acid, linolenic acid and others, D-galactose and D-mannose are present in the seed.

Medicinal and pharmacological activities

Antiparkinsonian activity: L-dopa has long been used for the treatment of Parkinson's disease in both modern medicine and ancient Indian therapeutics. In a recent study, rats fed with Mucuna pruriens endocarp (MP, 2.5 or 5.0 g/kg) showed superior activity to synthetic L-dopa (125 or 250 mg/kg). L-dopa, or MP at the same levels, plus carbidopa (SO mg/kg; controls received only carbidopa) was administered via gavage 1 h prior to testing, using a rotometer method as a measure of anti parkinsonian activity. Over 4 hours, dose for dose, MP was twice as potent as synthetic L-dopa in inducing contralateral rotation in the parkinsonian animal model. Thus, MP may contain unidentified antiparkinsonian compounds in addition to L-dopa or it may have adjuvants that enhance the efficacy of L-dopa. Comparison of the CNS profiles of L-dopa at 100 mg/kg and M. pruriens seed powder (3 g, containing 100 mg of L-dopa) showed equivalent hypothermic and anti-parkinsonian activity in rats and mice. MP had a faster onset of action and was significantly more active than LD. Both LD and MP significantly increased motor activity and both potentiated low-dose apomorphine-induced hypomotility. However, at high dose apomorphine-induced hypermotility LD had no effect but MP antagonised it. This differential effect suggests a different mode of action at dopamine post- and presynaptic receptor sites. In cardiovascular studies in animals, both L-dopa and MP caused a marginal potentiation of the pressor responses to adrenaline and antagonism of the carotid occlusion-induced pressor response to adrenaline. In haloperidol- and metoprolol-treated animals the adrenaline response was significantly potentiated by L-dopa but not by MP. The study showed that at equivalent doses, MP resembles L-dopa with respect to modulation of dopaminergic pathways, while the presence of other constituents in MP appears to contribute to improved anti-parkinsonian activity and greater tolerability. Efficacy and tolerability of HP-200, a preparation derived fromM. pruriens, in treating patients with Parkinson's disease was demonstrated. Sixty patients with Parkinson's (:t SD) age of 59:t9 years were treated in an open study for 12 weeks. Of these, 26 patients were taking synthetic levodopa/carbidopa formulations before treatment with HP-200 and the remaining 34 were levodopa naive. HP-200 was mixed with water and given orally. The Unified Parkinson's Disease Rating Scale (UPDRS) was used periodically during the 12-week evaluation. Statistically significant reductions in UPDRS and other scores were seen from baseline to the end of the 12-week treatment. Adverse effects were mild and mainly gastrointestinal in nature and no adverse effects were seen in clinical laboratory reports.

Hypoprolactinaemic effects: Mer oral pretreatment of patients with 15 g of the seed powder, chlorpromazine-induced hyperprolactinaemia was inhibited (by 40%) and was as effective as 0.5 g of L-dopa. No side effects were observed in the study.

Hypoglycaemic activity: Oral feeding of MP (at a dose of 200 mg per kg body weight per day for 40 days) to streptozotocin-induced diabetic mice reduced plasma glucose concentrations by 9%. It also prevented polyuria and partially but significantly (p < 0.05) prevented renal hypertrophy as compared to diabetic controls.22 Powdered seeds significantly decreased blood glucose I levels in normal as well as alloxan-diabetic I rabbits. It is not yet known whether the seeds act indirectly by stimulating the release of insulin or by a direct insulin-like action,

Antihaemorrhagic activity: The properties of the seed extract were demonstrated against Echis carinatus venom (EY). This venom affects the coagulative cascade, causing severe bleeding and haemorrhage. The extract attentuated the increased prothrombin activation induced by EV in vitro and could explain the protective effect in vivo.24 An aqueous extract of the leaves also showed a dose-dependent reduction in the time taken to clot for blood treated with a standardised dose of the same venom.

Spermatogenic activity: The total alkaloidal extract from the seeds produced an increase in the numbers of spermatozoa and the weights of the testes, seminal vesicles and prostate of treated rats. A stimulation of testosterone-induced androgenic activity was also observed in treated animals.

CNS adivity: Indolealkylamines isolated from Mucuna pruriens showed hallucinogenic activity, as measured by marked behavioural changes, antagonism of pentobarbitone-induced hypnosis, inhibition of reserpine-induced ptosis, hypothermia and sedation. It also reduced chlorpromazine-induced catatonia, and enhanced amphetamine toxicity in rats.

Aphrodisiac adivity: The drug has been used to improve cases of depressed libido and potency of both organic and psychogenic origin and management of premature ejaculation in humans. This is supported by experiments in rats in which the effect of the seeds on the general mating behaviour, potency (penile reflex test) and libido (mounting frequency) were studied. The drug produced a striking and sustained increase of sexual activity and androgenic activity was demonstrated. All the parameters of mating behaviour, including ejaculatory latency, were augmented and penile reflexes as well as mounting frequency were increased. Anabolic adivity: Plant administered orally to castrated adult and young male mice at a dose of 7.70 mg/animal was active. There was increased maltase activity of dorsoventral prostate and increase in fructose content of seminal vesicles.

Analgesic, antiinflammatory and antipyretic activity: An ethanol (95%) extract of the dried trichomes, administered intragastrically to rats, was active against acetic acid-induced writhing. It also showed analgesic activity as demonstrated by the hot plate method and was active against carrageenan-induced rat paw oedema, as was a similar extract of the leaves. Both extracts inhibited yeast-induced pyrexia.

Safety proftle

Pods, hairs and powder are externally irritant to the skin, eyes and mucous membranes. The stinging hairs produce extremely aggressive itching and burning, accompanied by long-lasting inflammation, caused by serotonin and mucunain, a proteolytic enzyme. The intake of the hairs should therefore be avoided, although administration of the herb in the form of extract is probably fairly harmless. The ethanoVwater (1: 1) extract of the fruit, when administered intra peritoneally to mice, was tolerated at a maximum dose of 1 glkg32 and that of the root was 250 mg/kg.