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Composition of Essential Oil, Radical Scavenging and Antibacterial Properties of Interspecific Hybrid Thymus × oblongifolius Opiz

Kristina Lo žienė, Aušra Šipailienė, Ramutė Maždžierienė, Juozas Labokas and Petras Rimantas Venskutonis

Institute of Botany, Nature Research Centre, Žaliųjų Ežerų g. 49, LT-08406, Vilnius, Lithuania

Department of Food Technology, Kaunas University of Technology, Radvilėnų pl. 19, Kaunas, LT-50254, Lithuania

Abstract: Radical scavenging and antibacterial properties of thyme extracts isolated from the two different Thymus × oblongifolius Opiz samples (TO1 and TO2) were studied. The oil of the TO1 was constituted mainly of hydrocarbon terpenes (83.4%), while the oil of the TO2 was composed mainly of oxygenated compounds with a -terpenyl acetate (37.9%) being the major one. The extracts isolated with hexane, acetone and ethanol from the whole and deodorized herb were tested for their radical scavenging capacity (RSC) in the model reaction systems containing stable radical DPPH • and cation radical ABTS •+. The extracts isolated with ethanol from undeodorized herb possessed the strongest RSC, while hexane extracts were not active. Undeodorized acetone extracts of the TO1 possessed higher RSC than those of the TO2, while undeodorized ethanol extracts of the TO2 were stronger radical scavengers than similar extracts of the TO1. The antibacterial activity of the extracts tested by using seven food pathogenic species depended on the species, extract concentration and extract type. Bacillus cereus, Staphylococcus aureus and St. epidermidis were more sensitive to plant extracts than Micrococcus luteus, Esherichia coli, Salmonella typhimurium and Enterobacter aerogenes.

Keywords: Interspecific hybrid Thymus × oblongifolius Opiz; radical scavenging capacity; DPPH; ABTS; antibacterial activity.