Chemical composition and antioxidative activity of essential oil of Thymus serpyllum L.

Abstract

Wild thyme (Thymus serpyllum L.) is a popular remedy regarding both tradetional and conventional medicine. It is used as the antiseptic, aromatic, expectorant, stomachic, antispasmodic, carminative and preservative substance. For the purpose of this paper, wild thyme essential oil was isolated from the dried herb T. serpyllum by hydrodistillation. Original semi-industrial distillation device SP-130 performing distillation by water and steam was used for the hydrodistillation of T. serpyllum essential oils. The temperature during the hydrodistillation in the device SP-130 ranged from 100-102 °C at atmospheric pressure, and the whole process lasted 5 hours. The isolated essential oil is a liquid of light yellow colour and the odour characteristic of the genus Thymus. Obtained yield of essential oil was 0.08 %, with 65 components identified in the tested essential oil. The most represented chemical groups are sesquiturpene hydrocarbons with 35.1%, and oxygenated sesquiturpenes with 34.8%. The main components of essential oil of T. serpyllum were: trans-nerolidol (24.2%), germacrene D (16.0%), thymol (7.3%), δ-cadinene (3.7%) and β-bisabolene (3.3%). The essential oil showed significantly better ability to neutralize DPPH free radicals (IC50 = 0.503 μL/mL) compared with synthetic antioxidants BHA and BHT. Synthetic chemical compounds such as BHA and BHT are used in food industry as antioxidants due to their ability to prolong the shelf-life of foodstuffs by protecting them against deterioration caused by oxidation, such as fat rancidity, colour changes, degradation of the flavor and loss of nutrient value. In recent years, there is a considerable interest in finding natural compounds that could replace sinthetic antioxidants because of adverse toxicological reports on many synthetic compounds. Lamiaceae herbs and their essential oils or extracts application has proven to be the effective preservation agents for the extension shelf-life of foodstuffs, indicating their potential use in food industry as functional ingredients and food additives. The antioxidant activity of extracts from some Lamiaceae herbs is comparable to that of the most common synthetic antioxidants BHT and BHA. Free radicals are a major cause of many degenerative diseases, such as atherosclerosis, cancer, cardiovascular diseases, inflammatory bowel diseases, skin aging, old age dementia and arthritis. Epidemiological data and randomized clinical trials provide sample indications that antioxidants play a fundamental role in the prevention of cancer and cardiovascular diseases. They act as scavengers of reactive oxygen species and metal chelators that protect human cells and reduce oxidative damages. Natural antioxidants are important in the food industry because they can have a double functionality, that is, they can be useful as a food preservation agents while providing important health benefits for humans by maintaining our health and preventing disease. This investigation showed that the essential oil of T. serpyllum can be an important source for the production and application in the food industry as nutritional supplements, functional food components or natural food antioxidants.

Cilj ovog rada bio je ispitivanje hemijskog sastava i antioksidativnog potencijala etarskog ulja majčine dušice (Thymus serpyllum L.). Etarsko ulje majčine dušice izolovano je iz osušene herbe T. serpyllum postupkom hidrodestilacije. Za hidrodestilaciju etarskog ulja T. serpyllum koriščen je originalni poluindustrijski destilacioni uređaj SP-130 koji radi na principu destilacije vodom i vodenom parom. Gasnohromatografskom analizom određene su najzastupljenije komponente kod etarskog ulja T. serpyllum: trans-nerolidol (24,2%), germakren D (16,0%), timol (7,3%), δ-kadinen (3,7%) i β-bisabolen (3,3%). Etarsko ulje je pokazalo značajno bolju sposobnost neutralizacije slobodnih DPPH radikala (IC50 = 0,503 μL/ml) u poređenju sa sintetskim antioksidansima BHA i BHT.