Investigating antimicrobial activity of hydroalcoholic extract and essential oil of Tymbra spicata against some pathogenic bacteria

Thymbra spicata (T. spicata) is a conventional medicinal herb which is commonly used in the traditional medicine system of Iran. The aim of this study was to assess the antibacterial activity of the essential oil and hudroalcholic extract of the plant T. spicata on some important bacteria.

The essential oil and extract of T. spicata were obtained by hydrodistillation and hydroalcoholic methods, respectively. Different concentrations of essential oil and hydroalcholic extract of the medicinal herb, T. spicata, were evaluated for their antibacterial activities against ten pathogenic bacteria (4 Gram-positive and 6 Gramnegative) by agar disc diffusion and macro Broth dilution method.

All bacteria showed a profound susceptibility to the essential oil and hydroalcholic extracts of the T. spicata. The essential oil was shown to be more effective against the examined bacteria. The zone of inhibition of the essential oil showed to be maximum against E. faecalis (28 mm) and M. morganii (30 mm). The hydroalcholic extract of T. spicata, showed the highest antibacterial activity against S. aureus (Gram-positive) and E. coli (Gramnegative) with the zone of inhibitions, 19 mm and 15 mm, respectively. The minimum inhibitory concentration (MIC) values for the essential oil and hydroalcholic extracts ranged from 7-60μg/ mL and 5-19 mg/ml, respectively against the tested bacteria.

This study revealed that the potential using of T. spicata as a source of antibacterial agents could be effectively used for medicinal and pharmaceutical purposes