Resumen de Quantitative HPLC Analysis of Rosmarinic Acid in Extracts of Melissa officinalis and Spectrophotometric Measurement of Their Antioxidant Activities.

Vera Canelas, Cristina Teixeira da Costa

• The students prepare tea samples using different quantities of lemon balm leaves (Melissa officinalis) and measure the rosmarinic acid contents by an HPLC�DAD method. The antioxidant properties of the tea samples are evaluated by a spectrophotometric method using a radical-scavenging assay with DPPH· (2,2-diphenyl-1-picrylhydrazyl). Finally the students are asked to correlate the measured antioxidant properties of the different teas with their contents in rosmarinic acid.