Hin: Sanay, Sana Ka Patt;
Mal: Sunnamukki, Chonnamukki, Nilavaka;
Tam: Nilavirai, Nilavakai;
Importance: Indian Senna or Tinnevelly senna is a shrub very highly esteemed in India for its medicinal value. The leaves are useful in constipation, abdominal disorders, leprosy, skin diseases, leucoderma, splenomegaly, hepatopathy, jaundice, helminthiasis, dyspepsia, cough, bronchitis, typhoid fever, anaemia, tumours and vitiated conditions of pitta and vata (Warrier et al,1994). It is used in Ayurvedic preparations; “Pancha Sakara Churna”, “Shat Sakara Churna” and “Madhu Yastyadi Churna” used for constipation. Its use is widespread in Unani system and some of the important products of this system containing senna are “Itrifal Mulayyin”, “Jawarish Ood Mulayyin”, “Hab Shabyar”, “Sufuf Mulliyin”, “Sharbat Ahmad Shahi”, etc. used as a mild laxative (Thakur et al, 1989).
Distribution: The plant is of Mediterranean origin. It is found in Somalia, Saudi Arabia, parts of Pakistan and Kutch area of Gujarat. It is largely cultivated in Tirunelveli, Ramanathapuram, Madurai and Salem districts of Tamil Nadu.
Botany: The genus Cassia, belonging to the family Caesalpiniaceae, comprises of a number of species, namely,
C. senna Linn. syn. C. angustifolia Vahl.
C. absus Linn.
C. alata Linn.
C. auriculata Linn.
C. burmanni Wight. syn. C. obovata (Linn.) Collad.
C. glauca Lam.
C. javanica Linn.
C. mimosoides Linn.
C. obtusifolia Linn. syn. C. tora Linn.
C. occidentalis Linn.
C. pumila Lam.
C. slamea Lam.
C. acutifolia Delile.
C. sophera Linn.
C. senna is a shrub or undershrub, 60-75cm in height with pale subterete or obtusely angled erect or spreading branches. Leaves are paripinnate. Leaflets are 5-8 in number, ovate-lanceolate and glabrous. Flowers are yellowish, many and arranged in axillary racemes. Fruits are flat legumes, greenish brown to dark brown and nearly smooth (Chopra et al,1980, Warrier et al,1994).
In commerce, the leaves and pods obtained from C. senna are known as “ Tinnevelly Senna” and those from C. acutifolia Delile. as “Alexandrian Senna”. The leaves of C. acutifolia are narrower than C. senna, otherwise both resemble to a large extent (Thakur et al, 1989). All the true Sennas have the portions of their leaves unequally divided. In some kinds the lower part of one side is reduced to little more than a line in breadth, while the other is from a quarter to half an inch in breadth. The drug known under the name of East Indian Senna is nearly free from adulteration; and as its properties appear identical with those of the Alexandrian and the price being less, it probably will supersede it in general practice. Its size and shape readily identify it (Graves, 1996).
Agrotechnology: The plant requires a mild subtropical climate with warm winters which are free from frost for its growth. Semiarid areas with adequate irrigation facilities are ideal for cultivation. Areas having high rainfall, humidity and poor drainage are not suitable. Light or medium loamy soils with adequate drainage and pH varying from 7.0-8.2 are preferable. In South India both summer and winter crops are possible. The plant is propagated by seeds. The seed rate required is 15-20kg/ha. Seeds are sown in October-November (winter rainfed crop) or in February-March (irrigated crop). Higher seed rate is required for unirrigated crop. Seeds are sown in lines 30cm apart. Application of 5-10t of FYM/ha before planting or raising a green manure crop is beneficial. About 40kg N and 25-50kg P2O5/ha applied as basal dressing and 40kg N/ha applied in 2 split dozes as top dressing gave better yield. While the rainfed crop is grown without irrigation, the irrigated crop requires 5-8 light irrigations during the entire growing season. The crop requires 2-3 weedings and hoeings in order to keep it free from weeds. Alternaria alternata causes leaf spot and dieback but the disease is not serious. In North India, the plant is attacked by the larvae of butterfly Catopsilia pyranthe which can be controlled by planting the crop in March-April instead of June-July. Under irrigated conditions, the first crop is obtained after 90 days of planting. The leaves are stripped by hand when they are fully green, thick and bluish-green in colour. The second crop is taken 4 weeks after the first harvest and the third 4-6 weeks after the second one. The last harvest of leaves is done when the entire crop is harvested along with the pods. Yield under irrigated conditions is nearly1.4t of leaves and 150kg pods/ha and under unirrigated conditions is 500-600kg leaves and 80-100kg pods/ha. The leaves are dried in thin layers under shade so as to retain the green colour and the pods are hung for 10-12 days to get dried. The leaves and pods are cleaned, graded and marketed (Husain et al, 1993).
Properties and Activity: Leaves contain glucose, fructose, sucrose and pinnitol. Mucilage consists of galactose, arabinose, rhamnose and galacturonic acid. Leaves also contain sennoside-C(8,8’- diglucoside of rhein-aloe-emodin-dianthrone). Pods contain sennosides A and B, glycoside of anthraquinones rhein and chrysophanic acid. Seeds contain -sitosterol (Husain et al, 1992). Leaves and pods also contain 0.33% -sterol and flavonols-kaempferol, kaempferin, and iso-rhamnetin. Sennoside content of C. acutifolia is higher ranging from 2.5% to 4.5% as compared to C. angustifolia ranging from 1.5 % to 2.5%.
The purgative activity of Senna is attributed to its sennosides. The pods cause lesser griping than the leaves. Leaf and pod is laxative. The leaves are astringent, bitter, sweet, acrid, thermogenic, cathartic, depurative, liver tonic, anthelmintic, cholagogue, expectorant and febrifuge.