Electrochemical Properties of Rosmarinic Acid and Its Analytical Application

he electrochemical behavior of rosmarinic acid, a main active content in a Chinese herbal medicine (Prunella vulgaris), was studied at a glassy carbon electrode. Two pairs of reversible redox peaks in pH 7.4 phosphate buffer, solution were reported for the first time. The mechanism of electrode reaction was also investigated by cyclic voltammetry, chronocoulometry, and square wave stripping voltammetry. Under optimal conditions, the peak current showed linear dependence on the concentration of RA in the range of 3.0 x 10(-9) to 1.5 x 10(-6) mol/L (r = 0.9989) with a detection limit of 1.8 x 10(-9) mol/L. The current method was successfully applied to quantitative determination of rosmarinic acid in Prunella vulgaris with relatively simple extraction procedures and satisfactory results. These current findings open new opportunities for researching valuable natural antioxidants for commercial exploitation by using voltammetry.