Potentiality of multivariate calibration methods in assessment of the components responsible for antioxidant activity of medicinal herbs using gas chromatography-mass spectrometry technique



Thyme and Trachyspermum ammi are medicinal plants that are famous in the world. These plants are used as antioxidants, antimicrobial, antispasmodic, antiseptic and anticancer. The purpose of this study is identification of potential antioxidant compounds in the essential oils of Thyme and Trachyspermum ammi. For this purpose the obtained chromatogram and antioxidant activity of essential oils were used. The antioxidant activity of essential oils was measured by DPPH radical scavenging test. By coupling of chromatographic data and antioxidant activity assisted by chemometric methods can identify the peaks potentially responsible for antioxidant activity. For this purpose, several linear multivariate calibration techniques such as principal component regression (PCR) and independent component regression (ICR) with different preprocessing methods were applied to chromatogram of essential oils of Thyme and Trachyspermum ammi. The results of these techniques were displayed as regression graphs, which peaks with negative regression coefficients cause antioxidant properties. Finally, GC–MS was used to indicate the structure of chemical components, which were responsible for antioxidant activity.