Characterization of the Essential Oil and Evaluation of Antibacterial Activity of Methanolic Extract of Stachys lavandulifolia Vahl.

Abstract

A B S T R A C T The present study was designed to identify the chemical composition of essential oil and evaluate in-vitro antibacterial activity of methanolic extract of Stachys lavandulifolia Vahl. against some clinical isolates. The essential oil of S. lavandulifolia Vahl. was obtained by headspace solid phase microextraction (HS- SPME) method. The HS-SPME coupled with gas chromatography/mass Spectrometry (GC/MS) was developed for the analysis of essential oil. Components were identified constituting more than 99.63% of the oil. Main components in the essential oil were as follows: myrcene (41.55%), L- -pinene (33.3%), -terpinene (12.16%), L- -pinene (5.06%), sabinene (1.34%) and - phellandrene (1.27%). Four Gram positive and six Gram negative clinical isolates were identified by standard microbiology techniques. In-vitro antibacterial activity of extract was evaluated against isolates by the broth microdilution method. The flowers of S. lavandulifolia methanolic extract exhibited more inhibitory effect against Gram positive isolates. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranged between 6.25 and 12.5 mg/ml, 12.5 and 25 mg/ml, respectively. Our findings indicate the promising antibacterial potential of S. lavandulifolia Vahl. extract which make it to be considered for pharmaceutical and medicinal purposes. K e y w o r d s Stachys lavandulifolia Vahl., Essential oil composition, Methanolic extract, Antibacterial activity