Chemical Variation and in vitro Antibacterial Properties of Volatiles from Tunisian Marrubium vulgare L. (Lamiaceae)

Abstract

In this paper, we have studied the chemical composition of the volatile fraction from six wild Tunisian populations of Marrubium vulgare L. growing wild in four bioclimatic zones were assessed by GC-FID and GC/MS analysis. Volatiles were individually tested against a large panel of microorganisms. In total, 37 compounds were identified with a predominance of diterpenes and alcanes. The main compounds were marrubiin (9-34 %), doctriacontane (13-25 %), and squalene (6-47 %). The variance analysis showed that amounts of the identified compounds varied significantly across the populations. Antibacterial activity of the volatiles was tested against three Gram-positive, three Gram-negative bacteria, and one pathogenic yeast. The volatiles exhibited interesting antibacterial activity. The inhibition zones and MIC values for bacterial strains, which were sensitive to the volatiles of M. vulgare, were in the range of 7–15 mm and 300-850 μg/mL, respectively. Greater interest and increased knowledge of the variation of the volatile composition of M. vulgare may be of significant value in the quest for new antimicrobial agents.

Key words:

• Marrubium vulgare
• volatiles
• chemical variation
• antimicrobial activity