COMMON INDIGO Indigofera tinctoria Papilionaceae
San:Nilini, Ranjani, Nilika, Neelam, Aklika, Asita, Bhadra; Ben, Guj:Nil; Hin:Gouli;
Mal: Neelamari; Tam: Averi; Tel: Aviri, Nili; Kan: Nili; Mar: Nali; Ori: Neli
Importance
Common indigo or Indian indigo is a branching shrub which grows upto 2m high.
Nili is a reputed drug produced from this plant which is used in ayurveda for the promotion of
hair growth and it forms a major ingredient of preparations like nilibhringadi oil. This is the
original source of natural indigo. Due to antitoxic property it is also a good remedy for
poisons. According to Bhavaprakasa, nili is purgative in action, bitter, hot, cures giddiness,
abdominal enlargement, vatarakta, gout and intestinal obstruction. The decoction or powder
of the plant is used in whooping cough, bronchitis, palpitation of the heart, enlargement of the
liver and spleen, dropsy, diseases of lungs and kidney, epilepsy and nervous disorders. A
poultice of the leaves is recommended in skin diseases, piles, ulcer and haemorrhoids. A
wine glass full juice of the leaves is administered in the morning with or without milk for
three days to those who have been bitten by mad dogs. Root decoction is given in calculous
diseases and used as an antidote to arsenic poisoning. The seed of the plant is powered and
steeped in arrack or rum, yield a tincture, which is used to distroy lice. Indigo, the dye
extracted from the leaves, is a soothing balm for burns and scalds, insect stings and animal
bites. The synonyms visaghni and sodhani indicate the antitoxic and laxative properties of
the drug nili, respectively (Aiyer and Kolammal, 1960).
Distribution
This plant is distributed in South and South East Asia, tropical Africa and is
introduced in tropical America. In India, it is found almost throughout and cultivated in many
parts.
Botany
Indigofera tinctoria Linn. syn. I. summatrana Gaertn, Pigmentum indicum belongs
to Papilionaceae family. This is a branching shrub which grows upto 2m high. Stems and
branches are green; branchlets silvery pubescent. Leaves are alternate, stipulate,
imparipinnate and got 7-13 leaflets which are elliptic-oblong, membraneous,1.7x0.9cm,
shortly mucronate, pale green or bluish. Flowers are small, rose-coloured in axillary
racemes. Calyx 5-cleft, gamosepalous; corolla papilionaceous; stamens diadelphous; ovary
sessile with a short incurved style ending in a capitate stigma. Pods are linear, cylindrical, 2-
5cm long, deflexed having 8-12 seeds.
Agrotechnology
The Indian indigo requires good sunlight and grows well in hilly areas. This is usually
propagated by seeds. Seeds are very small and the seed rate is 3kg/ha. Seeds require
pretreatment for good germination as the seed coat is hard. Seeds are mixed with sand and
ground gently to break the seed coat. An alternate method for enhancing germination is
dipping the seeds in boiling water for a second. After pretreatment seeds are broadcasted.
Broadcast the seeds preferably mixed with sand 2 or 3 times its volume to ensure uniform
coverage. The seedbeds should be covered with straw and irrigated. Seeds germinate within
15 days. Seedlings are ready for transplanting after one month. For the land preparation, the
soil is brought to fine tilth by ploughing 2 or 3 times. Cattle manure should be applied at the