Gas Chromatographic-Mass Spectrometric Analysis of Volatiles Obtained by HS-SPME-GC-MS Technique from Aerial Parts of Ziziphora capitata L., and Evaluation for Biological Activity

Abstract

Volatile constituent components from aerial parts of Ziziphora capitata L. were successfully separated using headspace solid-phase microextraction ( HS-SPME) approach, and were subsequently analyzed by means of GC and GC-MS instruments. The major volatile compounds were found to be pulegone ( 23.8%), p-mentha-3,8-diene ( 17.0%), alpha-pinene ( 11.4%), beta-pinene ( 11.3%) and p-menth-3-en-8-ol ( 8.3%) altogether involving more than 70% of the profile accounting for high frequency of monoterpene hydrocarbons. Moreover, the methanolic extracts of Z. capitata were evaluated for possible antioxidant and antibacterial activities. In this regard, antioxidant activity of the extracts was determined by monitoring the scavenging capability of the DPPH free radical. Antibacterial activity was evaluated against some of Gram-positive and Gram-negative bacteria using disc diffusion and broth microdilution methods. The minimum inhibitory concentration ( MIC) and minimal bactericidal concentration ( MBC) values varied over the ranges 3.12-12.5 mg/ml and 6.25-25 mg/ml, respectively. Our study revealed that methanolic extracts of Z. capitata exhibit strong and promising broad-spectrum activities against all the test isolates. For clinical isolates, the minimal MIC and MBC values were related to B. cereus and L. monocytogenes strains, whereas for the standard strains, both P. aeruginosa and S. aureus showed the lowest MIC and MBC values under the same conditions.