Elicitors act as signaling compounds that can induce and enhance the production of metabolites by activating biochemical pathways in response to external stress. Salicylic acid (SA) acts as a signaling molecule in plants in response to an attack by biotrophic pathogens whereas jasmonic acid (JA) is released in plants in response to wounds and herbivory. Both signaling molecules aid in plant chemical defenses by increasing the production of secondary metabolites. The present study investigates the effect of SA, JA, and the combination of both (SA + JA) on the andrographolide content in cell suspension cultures of Andrographis paniculata. Four different concentrations (25, 50, 75, and 100 μM) of SA and JA individually, and an equimolar combination of both SA and JA together, were administered to cell suspension cultures taken in triplicates at shake flask scale. Andrographolide content was estimated using high-performance liquid chromatography. Both SA and JA showed a positive effect on andrographolide content with the increase in their concentrations. SA at its highest concentration resulted in just a 0.18-fold increase (83.33 ± 6.7 μg/g DCW) in andrographolide content compared to control, whereas JA resulted in a 3-fold increase (211 ±5.8 μg/g DW); the combination of both SA and JA had an intermediate effect at all concentrations except one concentration (75 + 75 μM) which resulted in a 3.8-fold increase (280 ± 2.7 μg/g DW), in andrographolide content.
Key words: Andrographis paniculata, andrographolide, abiotic elicitors, salicylic acid, jasmonic acid, cell suspension cultures.
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