SPECTROPHOTOMETRIC DETERMINATION OF ROSMARINIC ACID IN PLANT-CELL CULTURES BY COMPLEXATION WITH FE2+ IONS

A spectrophotometric method for determining rosmarinic acid (alpha-O-c affeoyl-3,4-dihydroxyphenyllactic acid) in unpurified methanolic extra cts from Lavandula cell cultures is reported. It is based on a complex ation reaction of rosmarinic acid with Fe2+ to give a blue-dark produc t with lambda(max) = 572 nm and epsilon(572) = 3.82 x 10(3) l mol(-1) cm(-1). The stoichiometry of the reaction and the optimal conditions f or colour development are checked. The sensitivity and accuracy of thi s spectrophotometric method are compared with UV-spectral and HPLC met hods for determining rosmarinic acid in plant cell cultures; similar r esults are obtained.