The determination of some Thymbra species (wild thyme)' chemical content, antioxidant, anticholinesterase, urease, tyrosinase, cytotoxic, antimicrobial effects and their acaricide impacts on ticks

Lamiaceae (Labiatae) family is known for its rich species possessing medicinal properties and most of these species are very common in the Mediterranean region. In previous studies, it has been reported that species belonging to the Lamiaceae family have antioxidant, anticancer, anti-diabetic, neuroprotective, anti-inflammatory, anti-viral, anti-fungal and antibacterial effects. The genus Thymbra L., which belongs to the Lamiaceae family, is represented by a total of 5 taxa belonging to 3 species in Turkey. In the scope of the thesis, essential oil and ethanol extracts (root and stem parts) of the species belonging Thymbra L. Genus, Thymbra spicata L. var. spicata L., Thymbra sintenisii Bornm. Et Aznav. subsp. sintenisii Bornm. Et Aznav., T. sintenisii Bornm. & Azn. subsp. isaurica P.H.Davis were prepared. The chemical content, biological activity, nanoparticle formation potential and acaristic effects of the extracts were investigated in detail. Fatty acid content of petroleum ether extract of 3 Thymbra species was determined by GC-MS and it was determined that palmitic acid and α-linoleic acid were the dominant components. Essential oil content of Thymbra species was determined by GC-MS/FID. It was determined that carvacrol (%71.19-63.78) was the most abundant component in all 3 species. The aroma content of the species was determined by Headspace-GC-MS/FID and carvacrol (%24.71-20.79) and γ-terpinene (%42.02-4.98) were determined as the most abundant components. The phenolic content of ethanol extracts of underground and air parts of the species was determined by the LC-MS/MS method previously developed and validated by our group. The results showed that all ethanol extracts were rich in hesperidin (32910.02-3900.28 µg analyte/g extract). As a result of antioxidant determination studies all 3 species showed high antioxidant activity. In particular, ABTS (IC50:1.50±0.014-1.50±0.01 µg/mL) and CUPRAC (A0.5:1.30±0.12-1.52±0.01 µg/ml) activities of essential oils of all 3 species were determined to be quite high. The enzyme inhibition activity results of the studied species generally showed that all 3 species had the potential to be anticholinesterase enzyme inhibitors. In particular, essential oil samples were found to be more active in both AChE (%Inhibition:95.65±1.45-78.52±1.81) and BChE (%Inhibition:97.94±0.71-94.23±4.61) methods. It was determined that while essential oils showed urease enzyme inhibition activity, underground and air part ethanol extracts of Thymbra species did not show urease enzyme inhibition activity. In contrast, in the tyrosinase enzyme inhibition activity, it was determined that while the essential oils were not active, the underground and air part ethanol extracts showed activity. In addition, it was determined that the species did not show ACE enzyme inhibition activity. Antimicrobial activities of three essential oils of Thymbra species were determined according to Minimum Inhibition Concentration (MIC) values and it was determined that all three essential oils had moderate antimicrobial activity against the bacteria. It was also determined that all studied samples had low cytotoxic effect on HT-29 and MCF-7 cells and toxic effect on PDF cells. Characterization of silver nanoparticles synthesized with essential oils of Thymbra species was performed by Ultraviolet and Visible Light (Uv-Vis) Absorption Spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction Analysis (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDX) and Transmission Electron Microscopy (TEM). The data obtained from characterization studies proved the existence of synthesized silver nanoparticles. The 24-hour LC50 and % mortality values of the essential oils of the species and the silver nanoparticles synthesized with these essential oils on the nymphs of Hyalomma marginatum ticks were determined. The results showed that the essential oil and silver nanoparticles are generally severely toxic to the nymphs of Hyalomma marginatum.