Evaluation of the Chemical Profiling, Total Phenolic Composition, the Antioxidant and Antimicrobial Properties of the Essential Oils of Mentha piperita L., Salvia officinalis L., and Thymus vulgaris L.

Abstract

The purpose of this study was to determine the chemical composition, total phenolic composition, the antioxidant and antimicrobial properties of the essential oils (EOs) of Mentha piperita L., Salvia officinalis L., and Thymus vulgaris L. The essential oils of M. piperita L., S. officinalis L., and T. vulgaris L. were analyzed by means of gas chromatography-mass spectrometry (GC-MS) to demonstrate their chemical composition. The antioxidant properties of the EOs were evaluated with the 2,2-diphenyl-picrylhydrazyl (DDPH) free radical scavenging assay, their total phenolic compound contents were determined by the Folin Ciocalteau method, and their antimicrobial activities were evaluated by the disc diffusion assay. The major compounds in the contents of the essential oils of M. piperita L., S. officinalis L., and T. vulgaris L. were found to be eucalyptol, 1R-α-pinene, and o-cymene, respectively. In the 2,2-diphenyl-picrylhydrazyl (DDPH) assay, the EO of M. piperita L. (8,930.01 µMTE/g) demonstrated the highest antioxidant activity, followed by the activities of the EOs of T. vulgaris L. (157.76 µMTE/g) and S. officinalis L. (115.54 µMTE/g). The total phenolic compound contents of M. piperita L., T. vulgaris L., and S. officinalis L. were measured as 135.074, 0.242, and 0.221 mMGAE/g. All essential oils showed antioxidant activities and antimicrobial activities. The highest antimicrobial activity against S. aureus, A. nigeris, and C. albicans was determined in the EO of M. piperita L. within diameters of 42, 32, and 28 mm, respectively. These properties of essential oils are used in the pharmaceutical and food industries. The essential oils are approved as official medications in many countries and take place in their pharmacopoeias.