Ethanol extracts of thyme (Thyme sp. ) obtained by static and ultrasound assisted extraction – chemical composition and antioxidant activity

¹ Department of Food Technologies, Faculty of Technics and Technologies, Trakia University, 8600 Yambol, Bulgaria
² Department of Chemical Technology, University of Plovdiv “Paisii Hilendarski”, 4000 Plovdiv, Bulgaria
³ Department of Processes and Apparatus, University of Food Technologies, 4002 Plovdiv, Bulgaria
⁴ Department of Technology of tobacco, sugar, vegetable and essential oils, University of Food Technologies, 4002 Plovdiv, Bulgaria

^* Corresponding author: krasimira@This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The aim of this study is a comparative analysis of the chemical composition and antioxidant activity of extracts obtained with 70% ethanol from Thymus sp. collected from three different areas of Bulgaria by static and ultrasound assisted extraction. The extracts were analyzed using GC/MS. The main compounds were: thymol (32.20–82.35%), p-cymene (7.80–38.55%), γ-terpinene (0.74–5.60%), borneol (1.74–3.39%), carvacrol (1.48–4.83%), β-linalool (0.34–4.86%), and β-caryophyllene (0.75–3.43%). The total phenolic content was determined between 6.50 and 14.65 mg (GAE/g in the extracts from static extraction and between 3.24 and 13.73 mg GAE/g in the extracts from ultrasound assisted extraction. The antioxidant activities on the extracts measured by DPPH assay (between 12.47 and 13.59 mM TE/g for extracts from static extraction and between 12.24 and 12.43 mM TE/g for extracts from ultrasound assisted extraction) and ABTS assay (between 11.27 and 11,87 mM TE/g for extracts from static extraction and between 10.94 and 11.78 mM TE/g for extracts from ultrasound assisted extraction).