Pilu belongs to the Salvadoraceae family and is scientifically named Salvadora persica. In different traditional systems, it is known by various names such as Pilu in Ayurveda, Pilu or Miswak in Unani, and Khara Jhal, Chota Pilu, or Meswak in Hindi. It is popularly referred to as the Toothbrush Tree or Salt Bush Tree in English and is also traded under the names Khara Jhal and Toothbrush Tree. The roots of the plant are primarily used, especially in the manufacture of herbal toothpaste and oral care products.
Pilu: Morphology and Unique Features
Salvadora persica grows as a large shrub or small tree, especially well-suited to the Thar Desert. Its drooping, glabrous branches give it a distinctive desert plant appearance. It can grow in both mangrove-like conditions and under extreme drought and salinity, with birds aiding in seed dispersal. The plant produces three types of fruits like pink, purple, and white with purple fruits found to have the best seed traits such as weight, size, thickness, viability, and germination potential. Consequently, seeds from purple fruits are recommended for cultivation.
The leaf-shedding cycle is biannual, during October–November and February–March, yet the plant never becomes completely leafless. New foliage appears in April–May and again from September to December. In winter, leaves show anthocyanin pigmentation, turning reddish in response to cold stress. Galls are frequently observed on all plant parts except the roots and are believed to possess natural growth-promoting substances.
Floral and Fruiting Characteristics
Pilu flowers during September–October, bearing greenish-yellow flowers arranged in axillary and terminal compound panicles. The calyx is glabrous with rounded lobes, and the corolla is twice as long. Stamens protrude beyond the petals, and the fruit is a red drupe, either seeded or seedless. The fruits develop over three months and ripen between April and May. Under natural conditions, seed germination occurs during the monsoon months of July and August, taking advantage of increased soil moisture.
Geographical Distribution
Pilu is found throughout India’s arid and semi-arid zones, particularly in Rajasthan, Gujarat, and other dry regions. It survives and thrives under conditions of both salinity and drought, making it highly suitable for wasteland development, sand dune stabilization, and eco-restoration of degraded lands.
Climate and Soil Preferences
This plant prefers hot, arid climates with low rainfall and high temperature. For optimal growth, a soil mixture of sand:clay:FYM in a 1:2:1 ratio is ideal, though higher clay content is particularly beneficial for moisture retention. Its adaptability makes it a valuable component of dryland agroforestry and sustainable farming systems.
Propagation and Nursery Techniques
Propagation is done via seeds, preferably collected in April–May from purple-colored, healthy fruits. The seeds are soaked for 24 hours in the fruit pulp solution to enhance germination and shoot growth. Sowing is done in June under nursery conditions, placing two seeds per polybag at a depth of 1–2 cm. Around 15 grams of seed are needed to plant one hectare at a spacing of 5x5 meters.
Land Preparation and Fertilization
The land is initially ploughed in early June and left fallow for 20–25 days to allow solar exposure for weed drying, soil aeration, and decomposition of residues. A second ploughing is followed by field leveling. Fertilization includes NPK at 30:20:15 kg/ha, supplemented with hexameal. Half the nitrogen and the full dose of phosphorus and potassium are applied at the base, while the remaining nitrogen is top-dressed after 120 days of planting.
Transplanting and Maintenance
Seedlings are transplanted in the field at 5x5 meter spacing to ensure adequate sunlight and root expansion. Manual weeding and hoeing begin 20 days after transplanting and are repeated every 20 days during the rainy season. After rains, maintenance continues every 45 days for up to 3–4 years, depending on the growth stage.
Irrigation and Weed Management
For optimal development, fortnightly irrigation improves collar diameter, root yield, and biomass. Monthly irrigation supports plant height and overall growth. Manual hand weeding remains the most effective strategy for weed control in Pilu plantations, as no serious pest or disease threats have been recorded.
Harvesting and Post-Harvest Handling
Pilu fruits with seeds require 4–5 months to mature, typically from December to April–May. Although the entire plant has medicinal value, the roots are especially used for preparing Miswak toothpaste. Plants can be uprooted after two years for root harvesting at any time of year. Post-harvest, the plant is separated into leaves, stems, and roots using stainless tools. If not used fresh, plant parts must be stored in shaded, well-ventilated areas to retain quality by ensuring slow, continuous moisture loss.
Phytochemical Profile
The roots contain benzyl glucosinolate, elemental sulfur, salvadourea (a methoxylbenzyl derivative of urea), m-anisic acid, and sitosterol. The stem and root bark are rich in trimethylamine, and the seed oil contains fatty acids like myristic, lauric, and palmitic acid. The most significant compound is benzyl isothiocyanate (90% of steam-distillable root oil), known for its antimicrobial properties and role in preventing dental caries.
Therapeutic and Medicinal Uses
Pilu is widely used in Ayurvedic and Unani medicine. The roots and stems, especially when used as Miswak sticks, are valued for reducing plaque, tooth decay, and gingivitis. The plant's chemical constituents are also effective against skin infections, gingivostomatitis, and eye infections like conjunctivitis. The root bark acts as a stimulant and tonic, and the stem bark is beneficial in managing gastropathy and indigestion.
Culinary and Traditional Uses
While Pilu is primarily known for its medicinal use, the fruits, especially when ripe, are occasionally consumed by local communities in rural and desert regions. These small red drupes are known for their mild sweetness and tangy flavor. In some parts of Rajasthan and Gujarat, they are eaten fresh or used to prepare traditional chutneys and pickles. The fruits are also considered cooling and may be consumed during hot months for relief from heat and dehydration. Though not widely commercialized for food, Pilu’s edible fruit adds to its versatility as a native resource plant.
Pilu is much more than a desert shrub. Its multifaceted nature, ranging from traditional oral hygiene to medicinal healing, ecological resilience, and even culinary use makes it a plant of remarkable importance. Easy to grow under harsh climatic conditions, it supports sustainable livelihoods, dryland farming, and green cover development. With rising interest in traditional knowledge, natural remedies, and climate-resilient crops, Pilu offers immense potential for research, conservation, and community-based agroforestry models.
