Extracts from the roots were injected into a HPLC system. Compounds were chromatographed through a C8 column Ultrasphere ODS (4.6 x 250 mm), 4 µm particle size column (Agilent Technology, 1100 series). The mobile phase consisted of isocratic flow of acetonitrile (75058, JT Baker) and 0.01 M (NH4)₂HPO₄ (078401, JT Baker) in a relation of 43:57. The chromatographic system (Agilent Technology, 1100 series) consisted of a binary pump (Agilent 1200 Series binary pump). The solution was filtered trough a 22 µm nylon filter and degassed under vacuum.
   The injected samples (30 µL) were detected at 280 nm with a UV-vis detector (Agilent series 1200 series MWD) and subjected to a broad-range wavelength scan between 190 and 800 nm using a PDA-100 photodiode array variable UV-vis detector (Agilent series 1200 series MWD). The mobile phase was applied for all separations with a flow rate of 1.5 mL min^-1. Retention times and peak area of ajmalicine, serpentine and vindoline, identified previously in hairy roots of C. roseus were used to determine a compound’s possible presence in hairy roots elicitate with MeJA and SA. In all the cases the absorbance was measured at 280 nm and the area of the peaks show the difference in the molar extinction coefficient (ε) of every standard.