Multiple shoot induction and jasmonic versus salicylic acid driven elicitation for enhanced andrographolide production in Andrographis paniculata

Multiple shoot induction at an average of (15.25 +/- A 2.128 and 16.16 +/- A 3.851 shoots/explant) was obtained from Andrographis paniculata cotyledonary node explants on Murashige and Skoog's (MS) medium supplemented with 2.0 mg/L 6-Benzylaminopurine (BAP) and Zeatin, respectively after 8 weeks of culture. Further proliferation of cultures in MS + BAP medium at a maximum of 150 +/- A 18.40 multiple shoots was obtained from single cotyledonary node explants after three subculture (84 days) in vitro passage. Elicitation as yield enhancement strategy, a protocol was developed using multiple shoots to treat the cultures with jasmonic acid (JA) and salicylic acid (SA). Various concentrations of JA (1, 5, 10, 25, 50, 75 and 100 A mu M) and SA (10, 20, 50 and 100 A mu M) were used for elicitation. Treatment of JA at 1.0 A mu M concentration resulted in 1.322 % dry weight (DW) with 2.6-fold increase in andrographolide production after fifth week compared to 0.508 % DW in untreated control. However, JA treatment at 25 and 50 A mu M promoted 3.3, 3.0-fold enhancement in andrographolide production (1.624 and 1.481 % DW), respectively; after eighth week compared to control. Treatment of 10, 20 and 50 A mu M SA resulted in 3.0, 3.4 and 3.1-fold andrographolide content (1.479, 1.654 and 1.483 % DW), increase after eighth week, respectively; compared to control (0.478 % DW). This is the first report on elicitation of A. paniculata multiple shoot cultures using signal molecules (JA and SA). The present findings may be helpful for in vitro manipulation and enhanced production of andrographolides.