Comprehensive study of chemical composition and biological activity of Thymus pubescens Boiss. et Kotschy ex Čelak.

The use of Thymus species amongst the public and their importance in the scientific world is increasing day by day. In addition to being consumed as tea and spice, Thymus species are used as folk medicine for respiratory, digestive, skin, circulatory, genital, nervous, visual and urinary diseases. In this study, it was aimed to examine the essential oil and ethanol extract of the root and aerial parts of Thymus pubescens Boiss. et Kotschy ex Celak in the terms of their biological activity and chemical content. The phenolic content of the species was determined by LC-MS/MS, while triterpenoid content, the chemical composition of the essential oil as well as flavour was determined by GC–MS. In addition, their antioxidant and cytotoxic activities, as well as acetyl- (AChE) and butyrylcholinesterase (BChE), urease, tyrosinase, elastase, collagenase, HMG-CoA reductase and angiotensin-converting enzyme (ACE) inhibitory activities were studied. Thymol (53.33%) was determined as the major component in the essential oil, while β-fenchyl alcohol (43.87%) was determined as the major component of the flavour. According to the LC-MS/MS and GC–MS results, it was found that especially the aerial parts of the species have a high amount of rosmarinic acid (3875.76 µg analyte/g extract), quinic acid (2392.55), naringenin (970.39), oleanolic (92785.96) and ursolic (63373.32) acids. The essential oil of T. pubescens species was observed to show high activity in four antioxidant assays, e.g. inhibition of lipid peroxidation, DPPH and ABTS radical scavenging activity as well as CUPRAC, while the ethanol extracts showed moderate antioxidant activity. In enzyme inhibition assays, the aerial parts exerted marked BChE, elastase, and collagenase inhibitory activities (92.43±1.28%, 42.59±0.56, and 48.61±0.39 at 100 µg/mL, respectively). On the other hand, AChE, urease, tyrosinase, HMG-CoA reductase and ACE inhibitory activities of all extracts were from low to moderate levels. In particular, the aerial parts of the species displayed a high cytotoxic effect (vitality%: 6.82±0.01 at 200 µg/mL) in breast cancer (MCF-7) cell line. Due to its remarkable antioxidant capacity, high content of rosmarinic, oleanolic, and ursolic acids and especially BChE, elastase, and collagenase inhibitory activity, T. pubescens has the potential for using in food supplements, food preservatives, cosmetics, and pharmaceutical industries. [Display omitted] • The phenolic, triterpenoid and essential oil composition of Thymus pubescens determined by LC-MS/MS and GC–MS. • The high potential of butyryl-cholinesterase, elastase, and collagenase inhibitory activities. • High ursolic acid and thymol content of Thymus pubescens. [ABSTRACT FROM AUTHOR]