HPLC quantification of two isomeric triterpenic acids isolated from Mitracarpus scaber and antimicrobial activity on Dermatophilus congolensis

To quantify OA and UA in M. scaber, a new, simple and rapid high-performance liquid chromatography (HPLC) method compatible with MS detection was developed and validated. The mobile phase acetonitrile:H2O (85:15, v/v) was pumped through a C18 octadecylsilyl silica column at a flow rate of 0.6 ml/min and the eluate was monitored at 215 nm. The calibration curves constructed between 0.5 and 10 μg/ml showed linear relationships with good R2 values. The developed method was precise and reproducible with relative standard deviations (RSD) for these two active constituents between 0.22-2.06% (intraday) and 1.61-3.72% (interday) for concentrations from 0.5 to 6 μg/ml. Limits of detection and quantification were, respectively, 0.2 and 0.5 μg/ml.