flowers having fertile stamens. Male fascicle is 15-30cm long. The female flowers have
bifid stigma. Tubers are large, white and deep-rooted (upto 45cm) (Chadha et al, 1995).
3. D. deltoidea Wall. ex. Griseb.
D. deltoidea Wall. ex. Griseb. is distributed throughout the Himalayas at altitudes of
1000 - 3000m extending over the states of Jammu-Kashmir, H. P, U. P, Sikkim and further into
parts of W. Bengal. The glabrous and left twining stem bears alternate petiolate leaves. The
petioles are 5-12 cm long. The lamina is 5- 15 cm long and 4-12cm wide widely cordate. The
flowers are borne on axillary spikes, male spikes 8-40cm long and stamens 6. Female spikes
are 15cm long, 3. 5cm broad and 4-6 seeded. Seeds are winged all round. Rhizomes are
lodged in soil, superficial, horizontal, tuberous, digitate and chestnut brown in colour
(Chadha et al, 1995). D. deltoidea tuber grows parallel to ground covered by small scale
leaves and is described as rhizome. The tubers are morphologically cauline in structure with
a ring of vascular bundles in young tubers which appear scattered in mature tubers (Purnima
and Srivastava, 1988). Visible buds are present unlike in D. floribunda and D. composita
where the buds are confined to the crown position (Selvaraj et al, 1972).
Importance of Diosgenin
Diosgenin is the most important sapogenin used as a starting material for synthesis of
a number of steroidal drugs. For commercial purposes, its β-isomer, yamogenin is also taken
as diosgenin while analysing the sample for processing. Various steroidal drugs derived
from diosgenin by artificial synthesis include corticosteroids, sex hormones, anabolic
steroids and oral contraceptives. Corticosteroids are the most important group of steroidal
drugs synthesized from diosgenin. First group of corticosteroids regulates carbohydrate and
protein metabolism. The second group consists of aldosterone, which controls balance of
potassium, sodium and water in the human body. The glucocorticoids in the form of cortisone
and hydrocortisone are used orally, intramuscularly or topically for treatment of rheumatoid
arthritis, rheumatic fever, other collegen diseases, ulcerative colitis, certain cases of asthma
and a number of allergic diseases affecting skin, eye and the ear. These are also used for
treatment of gout and a variety of inflammations of skin, eye and ear and as replacement
therapy in Addison’s diseases. The minerato corticoides, desoxycorticosterone or
desoxycortone are used in restoring kidney functions in cases of cortical deficiency and
Addison’s disease.
Both male and female sex hormones are also synthesized from disosgenin. The main
male sex hormone (androgen) which is produced from disogenin is testosterone. The main
female sex hormones produced are oestrogen and progesterone. Recently oestrogen has also
been used in cosmetic lotions and creams to improve the tone and colour of skin. One of the
main uses of progesterone during recent years has been as antifertility agent for oral
contraceptives. These artificial steroids have increased oral activity and fewer side effects,
as they can be used in reduced doses. Oral contraceptives are also used for animals like
pigs, cows and sheep to control fertility and to give birth at a prescribed period in a group of
animals at the same time. These compounds are also used to reduce the interval between the
lactation periods to have more milk and meat production. Anti-fertility compounds are also
used as a pest-control measure for decreasing the multiplication of pests like rodents,
pigeons and sea gulls (Husain et al, 1979).
Although yam tubers contain a variety of chemical substances including
carbohydrates, proteins, alkaloids and tannins, the most important constituents of these yams
are a group of saponins which yield sapogenins on hydrolysis. The most important sapogenin
found in Dioscorea are diosgenin, yamogenin and pannogenin. Diosgenin is a steroid drug
precursor. The diogenin content varies from 2-7% depending on the age of the tubers.
Saponins including 5 spirastanol glucoside and 2 furostanol glucoside, 4 new steroid
saponins, floribunda saponins C, D, E and F. Strain of A and B are obtained from D.
floribunda (Husain et al, 1979). Rhizomes of D. deltoidea are a rich source of diosgenin