Gas Chromatographic-Mass Spectrometric Analysis of Volatiles Obtained by HS-SPME-GC-MS Technique from Stachys lavandulifolia and Evaluation for Biological Activity: A Review

Abstract

In this work, the volatile profile from the aerial parts of S. lavandulifolia using the HS-SPME-GC-MS technique along with phytochemical evaluations involving antioxidant and antibacterial activities of its methanolic extract have been screened. Volatile fractions were trapped on an SPME fiber and immediately transferred onto the injection port of a GC-MS instrument. The methanolic extract from the aerial parts of Stachys lavandulifolia was obtained and its antioxidant activity was determined using DPPH free radical scavenging assay. The antibacterial activity of the extract was also assessed using disc diffusion and broth microdilution methods against some Gram-positive and Gram-negative bacteria. The major volatile compounds were found to be myrcene (41.6 %), alpha-pinene (33.0 %), beta-phellandrene (12.2 %), beta-pinene (5.1 %), sabinene (1.3 %) and alpha-phellandrene (1.3 %) altogether involving more than 94 % of the profile accounting for high frequency of monoterpene hydrocarbons. S. lavandulifolia extract exhibited a rather desirable activity with an IC50 of 185.5 +/- 1.8 mu g/mL. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values varied over the ranges 6.25-12.5 mg/mL and 12.5-25 mg/mL, respectively. Our study revealed that methanolic extracts of S. lavandulifolia showed strong and promising broad-spectrum activities against all the standard strains as well as clinical isolates. Our findings imply the potential use of the proposed HS-SPME-GC-MS technique in characterization of the volatile fractions of plants. In addition, this study highlighted promising biological activities of the extract of S. lavandulifolia.