Characterization of aroma-active and phenolic profiles of wild thyme (Thymus serpyllum) by GC-MS-Olfactometry and LC-ESI-MS/MS

Abstract

The present study was designed to characterize the volatile, aroma-active and phenolic compounds of wild thyme. Volatile components of T. serpyllum were extracted by use of the purge and trap technique with dichloromethane and analyzed by gas chromatographymass spectrometry (GC-MS). The extraction method gave highly representative aromatic extract of the studied sample based on the sensory analysis. A total of 24 compounds were identified and quantified in Thymus serpyllum. Terpenes were qualitatively and quantitatively the most dominant volatiles in the sample. Aroma extract dilution analysis (AEDA) was used for the first time for the determination of aroma-active compounds of Thymus serpyllum. In total, 12 aroma-active compounds were detected in the aromatic extract by GC-MS-Olfactometry and terpenes were the most abundant compounds. Highperformance liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was used for the phenolic compounds analysis. 18 phenolic compounds were identified and quantified in the T. serpyllum. Luteolin 7-O-glucoside, luteolin and rosmarinic acid were the most abundant phenolics in this herb.

Effects of γ-Irradiation of Wild Thyme (Thymus serpyllum L.) on the Phenolic Compounds Profile of Its Ethanolic Extract

“…We did not fi nd apigenin-7-O-glucoside and apigenin-6,8-di-C-glucoside among them, although they were noted in previous studies [Kulišić et al, 2006;Boros et al, 2010;Sonmezdag et al, 2016]. Whereas a few other glucoside, glucuronide and rutinoside derivatives of luteolin and apigenin of wild thyme were described in literature [Fecka & Turek, 2008;Miron et al, 2011;Sonmezdag et al, 2016]. Flavanone aglycons: eriodictyol, eriocitrin and naringenin and their glycosides: eriodictyol-7-O-glucuronide and naringin, have so far been determined in wild thyme [Fecka & Turek, 2008;Boros et al, 2010;Miron et al, 2011;Sonmezdag et al, 2016].…”

“…Because retention times of peaks corresponding these compounds were shorter than t R of luteolin and apigenin, the compounds with not fully identifi ed structure were probably sugar derivatives of fl avones. We did not fi nd apigenin-7-O-glucoside and apigenin-6,8-di-C-glucoside among them, although they were noted in previous studies [Kulišić et al, 2006;Boros et al, 2010;Sonmezdag et al, 2016]. Whereas a few other glucoside, glucuronide and rutinoside derivatives of luteolin and apigenin of wild thyme were described in literature [Fecka & Turek, 2008;Miron et al, 2011;Sonmezdag et al, 2016].…”

“…Its presence in ethanolic extracts was confi rmed on the basis of a chromatogram recorded using a fl uorescence detector at excitation and emission wavelengths of 276 and 310 nm, respectively (Figure 3). Thymol, which in terms of structure is a monoterpene phenol, was determined as the main compound of essential oils of T. serpyllus [Nikolić et al, 2014] with the content of 1702 mg/100 g dry herb [Sonmezdag et al, 2016]. Thymol was also extracted in our study, because of its good solubility in ethanol, but its content in the extract was not very high (Table 1).…”

“…These effects are ascribed to secondary metabolites present in Thymus species. As the aromatic plant, thyme is rich in essential oils including mainly oxygenated monoterpenes [Nikolić et al, 2014;Sonmezdag et al, 2016]. A broad spectrum of phenolic compounds of thyme was identifi ed, too [Fecka & Turek, 2007;Boros et al, 2010;Miron et al, 2011].…”

Voltammetric determination of polyphenolic content as rosmarinic acid equivalent in tea samples using pencil graphite electrodes

“…The major source of RA is the rosemary, but it can be found in many plants as culinary or medicinal herbs (Sonmezdag et al 2016;Loganayaki et al 2013). It is classified as phenolic acid, one of the major plant phenolics, that act as antioxidants by trapping free radicals.…”