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

Introduction: Thymbra spicata (T. spicata) is a conventional medicinal herb which is commonly used in the folklore medicine system of Iran. Aim of the study was to assess the antibacterial activity of the essential oil and hudroalcholic extract of the plant T. spicata on some important bacteria. Materials & methods: 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 Gram-negative) by agar disc diffusion and macro Broth dilution method Results: All the 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 shown 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 (Gram-negative) 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. Conclusion: This study revealed the potential using of T. spicata as a source of antibacterial agents that could be effectively used for medicinal and pharmaceutical purposes.