A Novel Voltammetric Approach for the Rapid Quantification of Rosmarinic Acid in Origanum micranthum and Origanum minutiflorum

In this study, rosmarinic acid (RA) was isolated and quantitatively determined in extracts obtained from Origanum micranthum and Origanum minutiflorum using complementary analytical techniques. Following the isolation of RA from the ethyl acetate subextract of O. micranthum, spectrophotometric analyses were performed to evaluate its distribution in different solvent fractions, revealing a pronounced enrichment in ethyl acetate extracts of both species. In addition, an electrochemical strategy based on differential pulse voltammetry (DPV) was established for the rapid quantification of RA employing a boron-doped diamond (BDD) electrode. Under optimized experimental conditions, the method exhibited linearity over the concentration range of 0.2-80 µM with a detection limit of 0.061 µM. The applicability of the proposed approach was validated by successful analysis of plant extracts, yielding recoveries of 100.62% for O. micranthum and 100.74% for O. minutiflorum. The combined use of isolation, spectroscopic evaluation, and electrochemical quantification provides an efficient analytical framework for the determination of RA in the investigated Origanum extracts.