Production of Withanolides from Cell and Organ Cultures of Withania somnifera (L.) Dunal

Abstract

Withania somnifera (L.) Dunal. (Indian ginseng) is one of the most important medicinal plants used as a crude drug for its preventive and therapeutic purposes. Among the diverse constituents of Withania , withanolides are found to be the major components responsible for their biological and pharmacological actions. On the other hand, diffi culty in supplying the pure withanolides in suffi cient quantity prevents the development of Withania for clinical medicines. Field cultivation of Withania is time consuming and it needs extensive efforts for quality control as the growth is susceptible to many environmental factors including soil, climate, pathogens and pests. To overcome these problems, cell and organ cultures have been widely explored for more rapid and effi cient production of Withania biomass and withanolides. Recently, cell and organ cultures of W. somnifera have been developed in laboratory scale with a view to establish large scale production using bioreactors. Various physical and chemical parameters affecting the biomass production and withanolide accumulation have been investigated. For commercial withanolide production, fi eld grown plant material has generally been used but the quality of these products may be highly affected by different environmental conditions, pollutants and pests and pathogens like insects, fungi, bacteria and viruses, which can result in a heavy loss in yield and alter the medicinal content of plant. Plant cell and organ cultures are promising technologies to obtain plant-specifi c valuable metabolites [ 9 ]. Cell and organ cultures have a higher rate of metabolism than fi eld grown plants because the initiation of cell and organ growth in culture leads to fast proliferation of cells/organs and to a condensed biosynthetic cycle. Further, plant cell/organ cultures are not limited by environmental, ecological and climatic conditions and cells/organs can thus proliferate at higher growth rates than whole plant in cultivation [ 10 ]. Keywords Induction of Adventitious RootsRani et al. [ 14 ] induced adventitious roots from leaf explants of Withania by dip method. The leaf explants were dipped in different concentrations of IBA for different intervals of time and cultured the explants on the MS medium of different strengths. Adventitious roots were induced directly when leaf explants were cultured on half strength MS medium supplemented with a combination of IBA and IAA at 9.85 and 2.85 μM respectively. Other auxin combinations resulted in the formation of callus along with adventitious root induction. The adventitious roots were cultured in a 2.5 L bubble column reactor with 1,000 mL of half strength MS medium with the same hormonal concentration for 6 weeks and the roots were harvested and analyzed for the withanolide production. A maximum yield of 10 mg g ) for the induction of adventitious roots. The explants cultured on full strength MS medium produced only callus in all the concentrations tested, which hindered the induction of roots. Explants cultured on half MS m...