Dioscorea
Source, diagnostic characters,
constituents and uses
Objectives
At the
end of this lecture, student will be able to
• Source,
diagnostic characters, constituents and uses of Dioscorea
Dioscorea
Synonym
• Yam, rheumatism root
Source
• Dried tubers of Dioscorea deltoidea, D.
compositae and other species
Macroscopy
• Colur- light brown
• Odour – Odourless
• Taste – bitter
• Size- varies
Constituents
• Steroidal sapogenin – diosgenin– hydrolytic product
of saponin, dioscin
• Glycoside- Smilagenin, Epismilagenin, Yammogenin
• Starch- non edible- bitter
• Enzyme – sapogenase
Uses
• Source of diosgenin
• Diosgenin – precursor for corticosteroids, sex hormones,
oral contraceptives
• Rheumatic arthritis
Allied species
• D. floribunda
• D. villosa
• Costus speciosus – alternate source for
diosgenin- substitute for dioscorea