Steroidal Glycosides - Solanum

SOLANUM

Biological Source

It consists of dried berries of Solanum khasianum C.B. Clarke, belonging to family Solanaceae.

Geographical Source

The plant is found widely growing at various altitudes in India right from coastal region up to 2,000 m. It is found in hilly regions of Assam, Manipur, Sikkim, Nilgiris, Central India and also in Myanmar and China. Nowadays it is cultivated on commercial scales in Maharashtra.

Cultivation and Collection

In view of its solasodine content, it has commercial sig-nificance. Solasodine, a steroidal glycoalkaloid, has similar applications as that of diosgenin. The cultivation of this plant is scientifically studied and the observations of those trials are given here in brief. The seeds are used for propa-gation, either through nursery beds or by direct broadcast-ing. In February, the seeds are sown in nursery beds. The seed beds are covered with sand or farmyard manures and weeding is done periodically. When the seedlings show suf-ficient growth, they are transplanted into open fields. The raising in nurseries is preferred to direct broadcasting. The plant grows in various climatic and agricultural conditions. The well drained soil and sunny atmosphere are preferred. The seedlings are transplanted in moist soil at 50 x 50 cm distance. Urea, potash and superphosphate are given as fertilizers. In the initial period, irrigation is done once in a week and then in later stages as per requirement. After 6 months, the plants are harvested for collection of berries. They are immediately dried in shade or artificially at low temperature to reduce the large content of moisture.

Characteristics

It bears yellowish to greenish berries which are globose and 2.5 cm in diameter with compressed smooth brown seeds.

Chemical Constituents

The berries contain about 3% of steroidal glycoalkaloid called solasodine. A new glycoalkaloid solakhasianin having rhamnose and galactose as sugar components have been isolated. Mucilage surrounding part of the seeds contain highest amount of alkaloid. Immatured and over-ripe fruits contain negligible content of alkaloid, while it is maximum when fruits change colour from green to yellow. Colour change of fruits takes place about two months after setting the fruits to the plants. The berries also contain 8–10% of greenish-yellow fixed oil.

Uses

Solasodine is used as a precursor for steroidal synthesis. Like diosgenin, it is first converted to 16-dehydropregnenelone acetate. The latter is a precursor for steroids, like corticosteroids, pregnane and androstanes. All of these are useful as sex hormones, oral contraceptives, etc.