Chemical Composition of Essential Oil of Stachys pilifera Benth by Hydrodistillation, Head Space-Solid Phase Microextraction and Solvent Free Microwave Extraction Methods and QSRR Evaluation

摘要

Composition of the essential oils of Stachys pilifera (Lamiaceae) that obtained by hydrodistillation, solid phase microextraction and solvent free microwave extraction were analyzed by GC and GC/MS. In these methods cis-chrysanthenyl acetate was the main compound in the oils. The recognized compounds in the oil by hydrodistillation, solvent free microwave extraction and solid phase microextraction were depicted (92.52,95.1 and 97.95 %) respectively. Furthermore, a simple, descriptive and interpretable model, based on a quantitative structure-retention relationship, was developed using the stepwise-multiple linear regression approach for the prediction of the retention indices of essential oil components. A MLR model with five selected descriptors was obtained. Then, the MLR model was validated using the leave-one-out (LOO) and leave-group-out (LGO) cross validation. This model, with high statistical significance (R_(calibration)~2 = 0.953, F = 110.551, Q_(LOO)~2 = 0.932, Q_(LGO)~2 = 0.913 and R_(prediction)~2 = 0.966) could predict the retention indices of the essential oils with a percentage prediction error lower than 3 %.