Some traditional herbal tea in Anatolia chemical component and biological activities

In this master thesis, it is aimed to determine the various activities and bioactive components of herbal teas known as thyme, sage and mountain tea, which are naturally grown in the Southwest Anatolia Region, are used in gastrointestinal system, respiratory system and immune system disorders among the people and have not been studied in the form of tea extract (as consumed directly as diet) until today. In contrast to the organic solvents used in other studies, tea extracts in our study were obtained by brewing method, using water as the solvent. The volatile organic components of each tea extract were determined using the HS-SPME-GC/MS system. In terms of volatile organic compounds, carvacrol, thymol, β-caryophyllene and thymoquinone were detected as common major compounds in thyme teas (Origanum, Coridothymus and Satureja), while 1,8-cineol, β-pinene, bornyl acetate and β-caryophyllene were determined as co-major compounds. The presence and amount of 26 different reference compounds were determined using the phenolic component and organic acids HPLC-DAD system. Ferulic acid and rosmarinic acid were found to be common in all samples in the tea extracts studied. Moreover various biological activity methods were applied on tea extracts. Antioxidant activities were determined using five different methods (β-carotene color bleaching, DPPH free radical scavenging, ABTS cation radical scavenging, CUPRAC reducing power and metal binding). In enzyme inhibition activity studies; AChE-BChE inhibition activity, α-amylase enzyme inhibition activity, α-glucosidase enzyme inhibition activity and urease enzyme inhibition activity tests were applied. When evaluated in terms of biological activities, it was determined that herbal teas obtained from Coridothymus capitatus and Salvia officinalis species had higher bioactivities, and both species had bioactive compounds such as rosmarinic acid, myricetin, quercetin and chrysin. Thus, the relationships between the activities of the extracts with phenolic and organic volatile compounds were established. In this thesis, volatile organic components, biological activities and phenolic components of tea extracts prepared directly as dietary consumption of 11 plant species belonging to the Salvia, Sideritis, Coridothymus, Origanum and Satureja genera were examined in detail, with a different approach than those in the literature.