Separation of the major triterpenoid saponins in Bacopa monnieri by high-performance liquid chromatography

The first analytical procedure permitting the analysis of individual bioactive saponins (bacosides) in Bacopa monnieri is described. By using 3 μm C-8 column material (Luna C-8) and a mobile phase comprising of water and methanol the developed HPLC method enabled the baseline separation of seven major saponins within <30 min. Flow-rate, detection wavelength, and temperature were adjusted to 0.5 ml/min, 205 nm, and 40 °C, respectively. Identity of the analytes was confirmed in an LC–MS experiment, with all compounds being clearly assignable in negative ESI mode. Furthermore, the method was validated for limit of detection, linearity, precision, accuracy inter-day variation. Several B. monnieri samples (extract, plant material, commercial products) were successfully analyzed, each of them containing at least four of the seven reference compounds. Main components were either bacoside A3 or bacopaside II, least dominant showed to be bacopasides IV and V. The total saponin content in the samples varied from 1.1 to 13.0%.