Evaluation of phenolic compounds in herbal teas

The aim of this work was to assess and compare the radical binding activity and to identify the biologically active compounds of ETNO line of teas and the same composition tea blends made of medicinal plant raw materials derived from VMU Kaunas Botanical garden. In order to achieve the aim it was divided into several tasks: to determine the total content of phenolic compounds and flavonoids, total antioxidant activity of medicinal plant materials by means of spectrophotometry; make blends of teas adequate to commercial ones and determine the total content of phenolic compounds and flavonoids, total antioxidant activity of the blends and commercial teas; to compare the results obtaint for medicinal plant raw materials at different stages of vegetation teas and tea blends. The total content of phenolic compounds has been evaluated by Folin–Ciocalteu method. The total flavonoid content has been measured using the spectrophotometric method after the reaction with aluminum choride. The antioxidant activity has been measured using the spectrophotometric method with DPPH. Several commercially available teas: „Velvety Evening“, „Elfin“ and medicinal plant raw materials from VMU Kaunas Botanical Garden: camomile (Matricaria recutita L.), thyme (Thymus vulgaris L.), peppermint (Mentha piperita L.), raspberry leaves (Rubus idaeus L.), caraway seeds (Carum carvi L.), rosehip fruit (Rosa canina L.) and balm leaves (Melissa officinalis L.) were investigated. The total content of phenolic compounds was highest in Melissa officinalis raw material 79.04 mgRE/g, and „Velvety Evening“ tea mixture 76,48 mgRE/g. Minimum amounts were determined in Carum carvi L. 5.9 mgRE/g and „Elfin“ mixture 44.1 mgRE/g. Flavonoids highest amounts were in Mentha piperita L. raw material 40,33 mgRE/g and „Velvety Evening“ mixture 48.65 mgRE/g.[...]Biochemijos katedraGamtos mokslų fakultetasInstrumentinės analizės APCVytauto Didžiojo universiteta