The Italian senna,Senna italica, is a legume tree in the genus Senna. It is recognized by many other common names based on the regions it grows in. In India, it is known as “Neutral Henna”. Most botanists and scientists recognize this plant as “Senegal Senna”. Italian Senna is easily distinguishable through it’s many distinctive features. There are 3 subspecies of this plant based on the size of the inflorescence and the length of the petiole. The subspecies are italica, micrantha, and arachoides. In many regions, this plant is cultivated commercially and medicinally.

Geographic Distribution

Italian Senna is a native mostly in African countries from Cape Verde east to Somalia and south to South Africa. It is also native in Asia, from Middle East to Iran, Iraq, Pakistan and India to Sri Lanka. Later, this plant has been introduced to Caribbean and Venezuela. This plant is also introduced to USA and is currently located at New York Botanical Garden.
The subspecies italica is often found in West Africa, North Africa, Sudan, the Horn of Africa and from Yemen to Northwest India. But it is naturalized in some parts of South Africa. Subspecies micrantha is mostly seen from Southern Etiopia and Somalia southwards to Namibia, Botswana, Zimbabwe and Mozambique. Micrantha has been introduced to India too. Arachoides are limited to Namibia, Botswana and South Africa.

Habitat and Ecology

Senna italica can be seen in grassland of the drier regions of tropical Africa, from sea level up to 1850m altitude. Usually, it is found close to streams and in sandy and disturbed habitats, such as, waste places about towns and country dwellings, abandoned gardens, roadsides etc. This plant is adapted to warm temperature and may grow throughout the year.

Morphology

Individuals of this species are deciduous, perennial herbs, and shrubs upto 60 cm tall. The plant is woody throughout. Taproots are present in this plant. Stems are solid, usually less than 2 m tall. These stems or young twigs are glabrous or sparsely glabrous and sparsely to densely hairy. This species has compound leaves with pinnate veination. There are approximately 4-6 leaflets per leaf, which are arranged spirally and alternately. The leaflets are elliptical, and shortly hairy on both sides. There is a small reddish gland between each leaflet pair on the rhachis of arachoides subspecies. The stipules are usually have lanceolate-triangular shape. They are approximately 3–9 mm long and early spreading –deflexed.

Flowers and fruit

Flowering usually takes place during rainy season, but flowers can appear throughout the year in moist conditions. Senna italica is usually propagated by seeds as all angiosperms do. Treating the seed by abrasion improves germination.
Flowers of Senna italica, are actinomorphic inflorescence and axillary racemes, which are about 2–25 cm long. Petals of these flowers are usually yellow or orange in color, up to 13 mm long and are of obovate shape. Rhombic to ovate bracts are conspicuously present, but very small in size (up to 5mm long). The flower of Italian senna is bisexual, zygomorphic and 5-merous. It usually has 10 stamens (lower 2 are the largest; 5 are medium sized; 3 are short and sterile), Style up to 6 mm long and a superior ovary with short and stiff hair.
Italian Senna has freely dehiscent fruits. Fruits are oblong or ellipsoidal; they are strongly curved, falcate, bent or lunate shaped. The fruit may contain as many as 11 seeds. The seeds have elliptical line or depression and are wrinkled or rugose. Seeds are usually of olive, green or black color.

Medicinal Uses

The leaves, pods and seeds of Senna italica are mostly used as a purgative. The medicine made from this plant is taken to cure stomach problems, jaundice, fever, venereal diseases and biliousness. The fresh or dried and pulverized leaves are used as a dressing for skin problems. The flowers of this plant can be used to make tea, which are strongly laxative and induce labour. A maceration of the roots can be used to cure colic and influenza. Boiled roots were used as wound dressing at earlier times. For sore eyes, root infusion is used as eye drops. Medical researchers also suggest the use of Italian senna roots in treatments of indigestion, liver complaints, gall bladder disorder, vomiting, nausea and dismenorrhoea. In Malawi, root infusion is used to treat diarrhea in infants.

Other Usage

Reports on the uses of Senna italica is contradictory. In East Africa, it is eaten by most livestock, whereas in West Africa, it is often avoided. In Sahel regions, young seeds are eaten as snacks or a vegetable. On the other hand, the seeds are smoked in Mauritania. In India, the leaves are used as neutral henna or “blonde henna” to make the hair look glossy, but it seems to have a yellowish impact on hair rather than a reddish one. Fruit production of this plant is generally avoided as their sennoside content is low.

Diseases and Pests

Senna italica is known as the host of the root lesion nematode. Serious termite attacks are observed during perennial cultivation.

Production and international trade

The dried leaves and pods of Italian Senna are traded for medicinal uses. Dried, powdered leaves are traded internationally from Egypt or India as hair conditioner. Senna italica has lost its importance, as Senna alexandrina is the most popular for medicinal purposes. However, it is used widely within domestic markets for producing a mild laxative.

Genetic Resources and Breeding

There are collections of Senna italica in the gene banks in Israel, the United Kingdom and Namibia. By far, there is no threat of genetic erosion. Selection and breeding of this plant is not attempted, but it would be worthwhile if commercial production is envisaged.