Volatile compounds of Origanum onites L. herbal tea influenced by brewing durations

Abstract

The tisanes (herbal teas), which are prepared by steeping various parts containing bioactive ingredients of medicinal plants in hot water, have long been used for the prevention and treatment of human diseases. For the effective transfer of phytochemicals to water, the duration of brewing is one of the basic factors that determine the quality of tisanes. This study was carried out to investigate the volatile compounds of Origanum onites L. tisane influenced by 7 different brewing durations (1, 2, 3, 4, 6, 8, and 10 min) by SPME/GC-MS method. To clearly understand the qualitative changes of the tisanes that bear volatile ingredients, the volatile oil (VO) of the plant was also analyzed. Oxygenated monoterpenes (81.43%) were higher than other chemical groups in the VO. Carvacrol (73.2%) was observed as the predominant constituent of O. onites VO. Other major components of the VO were determined as linalool, γ-terpinene, p-cymene, β-bisabolene, caryophyllene, thymol, borneol, α-thujene, and α-terpinene. As a result of chromatographic analysis, oxygenated monoterpenes (96.05–98.19%) were the most major group in O. onites tisanes exposed to different brewing durations. Carvacrol was predominant constituent (84.34–92.6%) in all tisane treatments.The highest carvacrol contents of tisanes were observed at 4 (92.65%), 3 (92.19%), and 6 (91.61%) min. p-Cymene, γ-terpinene, linalool, and thymol were the other main compounds of O. onites tisanes. Based on the current findings, the greatest compounds group dissolved in water were oxygenated derivatives. As a general result, the most effective brewing duration in terms of volatile compounds diversity was determined in 2, 3, and 4 min. Also, the richest treatments in terms of carvacrol content were seen at 3, 4, and 6 min.