DETERMINATION OF THYMOLAND CARVACROL ON OREGANO LEAVES VIA HPLC FL

Abstract

Oregano (Origanum vulgare L.) is an aromatic native plant originated from the Mediterranean region and it's traditionally grown in the south of Peru. The crop has adapted well over 2600 m.a.s.l. Bellow this altitude, the concentration of essential oils (thymol and carvacrol) decreases. The development of this method is essential to provide tools for decision making to identify regions where one or more ecotypes can potentially grow and produce high quality of essential oils contents of thymol and carvacrol. As part of the activities, it was necessary to develop a protocol to quantify HPLC for the oregano crop. The proposed method uses a HPLC with a fluorescence detector, isocratic mobile phase of acetonitrile and water (ACN): H O (50:50), a column Purospher® STAR rp-18e (4.6 x 2 150mm, 5µm), flow 1 ml/minute, injection volume of 20 µLand run time of 15 minutes. The present method has a linearity greater than 0.999, precision ≤2.27, 2.4 intra-day, and ≤2.47 and 1.94 for daily measurements for carvacrol and thymol respectively. Detection limits (DL) and quantification limits (QL) were 0.0007 to 0.002 mg/Lfor, thymol and 0.002 to 0.005 mg/L for carvacrol with a recovery of 98.68% and 90.95% respectively. Results show that the protocol is an appropriate method to quantify carvacrol and thymol via HPLC in oregano leaves.