Pilocarpus microphyllus Seeds | (jaborandi)
LATIN NAME: Pilocarpus microphyllus
COMMON NAME: Jaborandi
Plant Profile
Jaborandi is an evergreen shrub of the citrus family from the humid forests of northeastern Brazil, grown for leaves that contain one of the few drugs still used to constrict the pupil. It reaches two to five metres, with a slender trunk, a rounded crown and pinnate leaves of small, glossy, dotted leaflets that smell faintly resinous when crushed. Small reddish flowers appear in upright spikes, followed by capsular fruits. The plant grows in the understorey of the Atlantic forest and the transition woods of Maranhão and Piauí, on sandy, acid soils, and it is slow to establish. Its leaves have been collected for the international drug trade since the nineteenth century, and wild populations have been reduced by repeated harvesting.
Science & Biotechnology
Pilocarpine, the alkaloid that gives the plant its value, is a muscarinic agonist that stimulates secretions and contracts the pupil. It remains a standard treatment for glaucoma and is used for dry mouth in Sjögren’s syndrome, which makes jaborandi one of the few rainforest plants still supplying a mainstream prescription drug. The alkaloid is concentrated in the leaflets and varies with age, shade and season, so plantations must be managed for quality rather than bulk. The species is one of about a dozen in the genus, several of which are also collected, and the trade mixes them. Genetic work on Brazilian populations shows structure between the Maranhão and Piauí stands, which matters because plantations founded from a narrow base may carry low chemical diversity. The plant is listed as vulnerable in Brazil, and cultivation is being promoted to take pressure off wild stands.
Uses & Benefits
The leaf is the commercial product, exported as dried leaf and processed for pilocarpine. In Brazilian folk medicine it was used as a stimulant, a diuretic and a hair tonic, and it appears in the pharmacopoeias of several countries. The plant is also grown as an ornamental shrub in tropical gardens, where its glossy foliage and small red flowers make a neat hedge, and it tolerates clipping. It is not a plant for cold climates; it needs heat, humidity and shade when young. Its leaves are toxic in quantity, causing sweating, salivation and slow heartbeat, so it should be kept away from children and pets. In agroforestry it can be grown under taller canopy, which suits its understorey habit.
Growing from Seed
Sow fresh seed, since viability drops within weeks. Use a light mix of leaf mould, sand and compost, surface-sow and cover with two millimetres of grit. Keep at twenty-five to thirty degrees with high humidity and shade from direct sun; germination takes three to six weeks. The seedling is slow and should stay in a shaded frame for its first year. Pot on into a rich, free-draining compost and grow on in filtered light. Plant out in a frost-free, humid site with acid soil and a mulch of leaf litter. Prune lightly to encourage bushy growth, and water through dry spells. The first harvestable leaf can be taken from the third year.
Our Take
A rainforest shrub that still supplies a modern eye drug. It needs heat, shade and humidity, and it is not a kitchen herb.
Related Reading
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