Optimization of nutritive factors in culture medium for the growth of hairy root and ajmalicine content in sarpgandha, Rauwolfia serpentina

Abstract

Aim: To optimize nutritive factors for hairy root development and ajmalicine content in Rauwolfia serpentina. Methodology: Optimization of nutritive factor was performed with 150 mg hairy root in 50 ml culture medium.Different ratio of nitrate and ammonium ions (0:20, 10:20, 20:20, 40:20, 60:20, 20:0, 20:10, 20:40, 20:60), different phosphate concentration (0.625 - 5.0 mM), different culture medium (MS, B5, ½ MS, ½ B5), different pH (4.0- 7.0), different concentration (2% - 4%) of carbon sources (sucrose, fructose, glucose, galactose) were evaluated for dry weight (growth index) and ajmalicine content enhancement. Results: Growth of hairy root was observed best in ½ MS media.Sucrose was found significantly best among the other tested carbon sources in terms of higher growth index (4.31)and ajmalicine content (0.0068 mg g-1d.wt.) at 3% and 3.5% sucrose concentration.NH4+ to NO3- ratio (mM) of 40:20 and 20:10 was significantly optimum for growth index (7.12) and ajmalicine content (0.0112 mg g-1 d. wt.). Culture media supplemented with 0.625 mM phosphate concentration resulted into significantly higher ajmalicine content (0.0074 mg g-1d. wt.).However,increase in phosphate concentration (0.625 - 5.0 mM) resulted into continuous enhancement of growth index. Optimum pH of 6.0 and 6.5 was observed suitable for higher growth index (5.19) and ajmalicine content (0.0076 mg g-1d.wt.), respectively. Interpretation: Standardization of nutritive factor in culture media resulted in a development of alternative strategy for large scale production of ajmalicine, a pharmaceutically important alkaloid.