San: Pushkara, Kashmeera, Kemuka;
Hin: Kebu, Keyu, Kust;
Ben: Keu, Kura
Mal: Channakkizhangu, Channakoova;
Tam: Kostam; Mar: Penva;
Importance: Costus is one of the plants which contains diosgenin in its rhizome. It is widely used as starting material in the commercial production of steroidal hormones. The rhizomes are useful in vitiated conditions of kapha and pitta, burning sensation, flatulence, constipation, helminthiases, leprosy, skin diseases, fever, hiccough, asthma, bronchitis, inflammation and aneamia. It is used to make sexual hormones and contraceptives (Warrier et al,1994).
Distribution: The plant is widely distributed in Asia and other tropical countries like India, Nepal, Pakistan, Sri Lanka and China. In India, it occurs mostly in Arunachal Pradesh, Meghalaya, Nagaland, Tamil Nadu, Assam, Tripura and Kerala.
Botany: Costus speciosus (Koenig.) Sm. belonging to the family Zingiberaceae consists of two varieties viz., var. nepalensis Rose., found only in Nepal and Arunachal Pradesh and var. argycophyllus Wall., having a wide distribution in India.
The plant is a succulent herb with long leafy spirally twisted stems, 2-3m in height and horizontal rhizomes. Leaves are simple, spirally arranged, oblanceolate or oblong, glabrous above, silky pubescent beneath with broad leaf sheaths. Flowers are white, large, fragrant, arranged in dense terminal spikes. Bracts are bright red. The single stamen present is perfect, lip large with incurved margins. Fruits are globose or ovoid capsules with obovoid or sub- globose seeds (Warrier et al,1994).
Agrotechnology: Costus can be raised under a wide range of agroclimatic conditions. It prefers sandy loam soil for good growth. Propagation is by rhizomes. The best season for planting is April- May. The seed rate recommended is 2-2.4t/ha. The spacing adopted is 50x50cm. After an initial ploughing FYM or poultry manure should be applied at the rate of 30t/ha and the field is to be ploughed again irrigated and prepared to obtain a fine seed bed. Furrows are opened and the rhizome pieces are placed horizontally at a depth of 8-10cm and covered with soil. Care is taken to place the eye buds facing upwards. After 70-75 days about 90-95% sprouting is obtained. Desiccation of the young sprouts have been observed in the hot summer months, necessitating liberal water supply during the period. As September-November is the period of maximum tuberization at least two irrigations should be given at that time. One during the sprouting period of the crop followed by two more keeps the crop fairly free of weeds. Application of 37t/ha of poultry manure and fertilizers, 60kg P2O5 and 40kg K2O /ha as a basal doze, along with 80kg N/ha applied in 3 equal split dozes will take care. Crop is harvested at the end of seven months. Harvesting includes 2 operations, cutting the aerial shoots and digging out the rhizomes. Cost of production of diosgenin ranges from Rs. 271-300/kg (Atal, et al,1982).
Properties and activity: Tubers and roots contain diosgenin, 5 -stigmast-9(11)-en-3 ol, sitosterol- -D- glucoside, dioscin, prosapogenins A and B of dioscin, gracillin and quinones. Various saponins, many new aliphatic esters and acids are reported from its rhizomes, seeds and roots. Seeds, in addition, contain – tocopherol. Saponins from seeds are hypotensive and spasmolytic. Rhizomes possess antifertility, anticholinestrase, antiinflammatory, stimulant, depurative and anthelmintic activities (Hussain et al, 1992).