Determination of antimicrobial activity and molecular genotypes of different thyme species grown in Turkey

In this study, it was aimed to determine the antimicrobial activities and genotypic characterization of the species Thymbra spicata var. spicata L., Thymus vulgaris L., Thymus citriodorus (Schreb), Thymus cilicicus Boiss. & Bal., Origanum syriacum L., Origanum minutiflorum O. Schwarz & P.H. Davis, Origanum onites L., Origanum saccatum P.H. Davis, Origanum vulgare L. ssp. gracile (C. Koch) Letswaart, Origanum vulgare L. ssp. hirtum (Link) Letswaart ve Thyme variety candidate (Tekin, 2017) who are blong to the genera Thymbra, Thymus and Origanum respectively in the Labiatae family in Turkey. A total of 33 extracts were obtained as a result of the 24-hour extraction process with 3 different solvents (hexane, ethanol and chloroform) from each plant using the Soxhlet device. The antimicrobial activity of the extracts against to Eshericia coli ATCC 25922, Pseudomonas auriginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 bacteria was determined using the disk diffusion method. When extracts obtained from different thyme species with three different solvents were applied on four different bacteria at three different concentrations, it was determined that the highest antimicrobial effect was observed in S. aureus bacteria, and in the second place was observed in E. facealis bacteria. It was found that antimicrobial active substances were obtained more effectively than hexane in extracts obtained with ethanol and chloroform used as solvents. Effectiveness levels in antimicrobial activities according to sigma value in ANOVA results indicated that the antimicrobial activities were significant in the species Thymbra spicata var. spicata L., Thymus vulgaris L., Thymus citriodorus (Schreb), Thymus cilicicus Boiss. & Bal., Origanum syriacum L., Origanum vulgare L. subsp. hirtum (Link) Letswaart ve Tyme Variety candidate (Tekin, 2017), while the antimicrobial activities were not significant in the species Origanum minutiflorum O. Schwarz & P.H. Davis, Origanum onites L., Origanum saccatum P. H. Davis ve Origanum vulgare L. ssp. gracile (C. Koch) Letswaart. Molecular genotypes of thyme species were characterized by using 10 ISSR primers. The Pearson's correlation results between the antimicrobial effects of the extracts on four different bacteria at three different concentrations and the ISSR loci showed very strong positive correlations. Since ISSR markers show dominant inheritance, these results are preliminary studies for future studies and also encourage further studies using more effective codominant markers. In addition, ISSR markers were successful in clustering the thyme species analyzed in this study according to their genus in general. As a result, it was observed that different thyme species are highly effective in maintaining their anti-microbial activities.