Stability studies of crude plant material of Bacopa monnieri and quantitative determination of bacopaside I and bacoside A by HPLC.

INTRODUCTION: Bacopa monnieri (BM) contains several dammarane-type triterpenoid saponins including bacopaside I and bacoside A. These bioactive compounds may be used as chemical markers for the quality control of different BM products used for promoting mental health and intellect.

OBJECTIVE: Quantification of bacopaside I and bacoside A in crude plant material of BM stored under the stability study conditions by HPLC.

METHODOLOGY: Crude BM samples were stored at long-term (LS; 30°C and 65% RH), accelerated (AS; 40°C and 75% RH) and real-time (RT) study conditions. HPLC of BM extracts was carried out using a LiChroCART Purospher® STAR RP-18 endcapped column along with a guard column, Purospher STAR RP 18e 4.0 4.0 mm 5 µm using a gradient of acetonitrile (A) and water containing 0.05% (v/v) orthophosphoric acid (B) at a flow rate 1.5 mL/min with UV detection at 205 nm.

RESULTS: The linear range of bacopaside I and bacoside A was 0.2 to 1 mg/mL. With the help of a regression equation the coefficient of determination (r²) values for bacopaside I and bacoside A were found to be > 0.999 and > 0.994 respectively. Relative standard deviation (RSD) values were < 4.0 for all the concentrations injected (n = 3). The HPLC study indicated that BM samples kept under LS condition are rich in saponin contents as compared with the samples stored under AS and RT study conditions.

CONCLUSION: The study indicated that BM plant material should be used fresh to obtain maximum concentration of active saponins or it should be stored under LS conditions up to 3 months.