The Bioscan, 3(4): 387-392, 2008
An International Quarterly Journal of Life Sciences
web site: www.thebioscan.in 
BIOTRANSFORMATION OF CHOLESTEROL INTO DIOSGENIN IN RHIZOME-DERIVED 
CALLUS CULTURES OF COSTUS SPECIOSUS (KOENIGI) SMITH
CH. HARITHA* AND J. K. BHALLA
Cytogenetics and Biotechnology Laboratory, Department of Botany, Osmania University,
Hyderabad - 500 007 (A P) INDIA
E-mail: haritha_botany@yahoo.com

KEY WORDS
Costus speciosus
Biotransformation
Diosgenin
Callus cultures Received on: 18.04.2008 Accepted on: 27.10.2008 *Corresponding Author

ABSTRACT

Costus speciosus (Koenigi) Smith is an important medicinal plant that produces an important phytochemical diosgenin used in the preparation of drugs such as progesterone, testosterone and cortisone. Callus cultures were derived from the rhizome and the biotransformation of cholesterol and its effect on diosgenin yield was studied. The callus obtained in Schenk and Hilderbrandt (SH) medium supplemented with 1.0 mg L-1 2,4-D + 1.0 mg L-1 IAA + 0.5 mg L-1 Kn when subcultured in medium containing various concentrations of cholesterol and1.0 mg L-1 2,4-D, 3.0 mg L-1 IAA and 5.0 mg L-1 Kn singly showed low callus growth rate (CGR) and high product accumulation. Kn at 5.0 mg L-1 showed the best response wherein a 70 percent increase in diosgenin over the control in 6-week culture supplemented with 50 mg cholesterol per 100 mL medium was observed. The callus that was white-brownish in colour and friable in nature showed maximum diosgenin accumulation. An inverse relationship was observed between callus growth and the secondary product accumulation.