Analysis of phenolic compounds in Greek plants of Lamiaceae family by HPLC

The objective of the current study is the simultaneous determination of 24 phenolics including carvacrol and thymol, in plants of Lamiaceae family by developing a simple and reliable reversed-phase high-performance liquid chromatographic method involving diode array detection. The separation of 24 compounds was achieved on a reversed phase C-18 column kept at 30 degrees C by gradient elution with a flow rate of 1.3 mL/min. The method was validated for specificity, linearity and intra- and inter-day precision. The limit of detection and quantification for all analytes were small, ranging from 0.002 to 0.16 and 0.01 to 0.48 mu g/mL, respectively. This method was successfully applied to detect and quantify phenolics present in the plants. It was found that the amount of phenolics in both extracts (water, and methanolic) decreased in the following order: Origanum vulgare ssp. hirtum > Thymus capitatus > Satureja thymbra > Melissa officinalis > Rosmarinus officinalis. The limit of quantification values are low enough to detect and quantify successfully small amounts of 24 phenolics in the plants of Lamiaceae family. Generally, Melissa officinalis exhibited the highest antioxidant activity among the samples followed by Origanum vulgare ssp. hirtum. The developed method, is simple and reliable with satisfactory sensitivity and precision and is ideally suited for routine analysis. (C) 2017 Elsevier GmbH. All rights reserved.