High‐performance liquid chromatography and LC‐ESI‐MS method for the identification and quantification of two biologically active isomeric coumarinolignoids cleomiscosin A and cleomiscosin B in different extracts of Cleome viscosa

A rapid, sensitive and simple reverse‐phase high‐performance liquid chromatographic–electrospray ionization–mass spectrometry method for simultaneous determination of cleomiscosin A and cleomiscosin B has been developed and validated. The isomeric coumarinolignoids cleomiscosin A ( 1 ) and cleomiscosin B ( 2 ) were separated on a Waters symmetry C 18 column with a solvent system composed of acetonitrile–methanol (1:2) and acetic acid–water (0.5 : 99.5) in a gradient elution mode. The absorption at 326 nm was chosen as the measuring wavelength in which resolution and baseline separation of compounds 1 and 2 could be obtained. The identity of the two isomeric compounds 1 and 2 in the samples were determined on a triple quadrupole mass spectrometer with ESI interface operating in the positive mode. Calibration curves were linear ( r 2 > 0.993) over the concentration range 20–200 µg/mL for cleomiscosin A and 10–200 µg/mL for cleomiscosin B with acceptable accuracy and precision, respectively. The intra‐day and inter‐day precision were 1.13 and 0.82% for cleomiscosin A and 1.78 and 1.28% for cleomiscosin B, respectively. The validated method was successfully applied for the analysis of the above two compounds in different extracts of Cleome viscosa . Copyright © 2008 John Wiley & Sons, Ltd.