Thyme essential oils are well recognized by their excellent biological activities and the antimicrobial activity of Portuguese thyme essential oils has been investigated with promising results, particularly against food borne pathogens. In this study the potential antimicrobial activity of the essential oils of five species of Thymus (Lamiaceae), namely Th. caespititius Brot., Th. camphoratus Hoffmanns. & Link, Th. capitellatus Hoffmanns. & Link., Th. carnosus Boiss. and Th. zygis L. was evaluated against Candida albicans, Haemophilus influenza, Helicobacter pylori, Listeria monocytogenes, Salmonella enterica and Streptococcus pneumoniae. H. pylori strains were the most susceptible bacteria, particularly to the essential oils of Th. caespititius (Planalto Central), Th. zygis (Rebordãos) and Th. caespititius (Pico) which minimum inhibitory concentration (MIC) values ranged from 0.05 to 0.08 mg.mL-1. Th. caespititius essential oil from Planalto Central or its main component, carvacrol significantly (p<0.05) inhibited the intracellular growth of H. pylori, and showed no citotoxicity to the gastric cell line. Our results suggest the potential of this essential oil and its main component as a promising tool as anti-Helicobacter agent potentiating the eradication of this important gastroduodenal pathogen.

Neste ensaio avaliou-se o efeito de diferentes misturas de substrato comercial e vermicomposto na produção de biomassa, composição química e rendimento dos óleos essenciais de Thymus zygis. Utilizaram-se 5 substratos resultantes da mistura de um vermicomposto (V) com um substrato orgânico comercial (O), em cinco proporções diferentes (v/v): V100 (100%V); VO75-25 (75%V+25%O); VO50 -50 (50%V+50%O); VO 25-75 (25%V + 75%O) e O100 (100%O). A inclusão do vermicomposto no substrato não melhorou a produção de biomassa. Na modalidade O100 produziu-se mais biomassa, tendo sido na modalidade VO25-75 onde se obteve o valor mais baixo. Na modalidade V100 todas as plantas secaram tendo-se ainda apresentado nesta modalidade o valor mais elevado de pH e de densidade real e inversamente o menor valor de espaço poroso total. Os monoterpenos oxigenados predominaram nos óleos extraídos das plantas nas modalidades O100 e VO25-75, contrariamente ao que se verificou para os monoterpenos não oxigenados tendo estes predominado nas modalidades VO75-25 e VO50-50. A concentração de timol foi elevada nas misturas testadas, em particular na modalidade VO25-75.

In this trial we evaluated the effect of different mixtures of organic growing media substratum and vermicompost and their physical properties on biomass, chemical composition and yield of essential oils of Thymus zygis. Five treatments were established based on two types of organic materials (O, commercial growing media, and V, vermicompost). The following proportions were studied (v/v): V100 (100%V); VO75-25 (75%V+25%O); VO50-50 (50%V+50%O); VO 25-75 (25%V+75%O) and O100 (100%O). The inclusion of vermicompost did not improve biomass production. The treatment O100 produced more biomass and the lowest was obtained in VO25-75. On V100 treatment all plants were dead and also have showed the highest pH and particle density and conversely presented the lowest value of total pore space. Oxygenated monoterpenes predominated in the oils extracted from plants in O100 and VO25-75, contrary to what was found for non-oxygenated monoterpenes having these prevailed in VO75-25 and VO50-50. The concentration of thymol was high in the mixtures tested, particularly in VO25-75.