Authors:Erika-Beáta Kerekes, Anita Vidács, Julianna Jenei Török, Csilla Gömöri, Tamás Petkovits, Muthusamy Chandrasekaran, Shine Kadaikunnan, Naiyf S. Alharbi, Csaba Vágvölgyi, and Judit Krisch
The anti-listerial effect of marjoram, thyme essential oils (EOs) and thymol on Listeria monocytogenes inoculated chicken breast fillets was investigated. Before inoculation the fillets were pretreated by washing or not under running tap water. Inoculated samples were kept at 6 °C for 24 h to allow the growth of L. monocytogenes. After this, the fillets were put in marinating solutions containing salt (5%) and EOs or thymol in MIC/2 concentration established in vitro. Total germ count (TGC) and L. monocytogenes count was monitored on the meat surface and in the marinating solutions following 24 and 48 h storage at 6 °C. Thyme and thymol reduced significantly Listeria cell count (1–3 log CFU) in both samples. They also gave good flavour to the fried meat. The doses of EOs used were optimal for antimicrobial efficiency and had a pleasant flavour effect. Washing was not efficient in reducing total germ count.
Authors:Khabat Noori Hussein, Tímea Molnár, Richard Pinter, Adrienn Toth, Emna Ayari, Laszlo Friedrich, Istvan Dalmadi, and Gabriella Kiskó
monoterpenes can be classified based on their diverse functional groups: terpinene, pinene; alcohols, e.g. geraniol; aldehydes, e.g. citral; ketones, e.g. camphor or phenols, e.g. thymol and carvacrol ( Bakkali et al., 2008 ) ( Fig. 1 ). Some of these active
Authors:Zsuzsanna Pluhár, Marianna Kocsis, Anett Kuczmog, S. Csete, Hella Simkó, Szilvia Sárosi, P. Molnár, and Györgyi Horváth
Chemical and genetic differences of twenty taxa belonging to four Thymus species were studied in order to determine whether molecular characters and essential oil components could be used as taxonomic markers and to examine the correlation between them. Plant samples, representing different taxa and geographic regions, were collected from experimentally grown populations. Essential oil samples were analysed by GC/MS and cluster analysis of volatile composition resulted in segregation of thymol chemotypes from sesquiterpenic ones. Thymol was characteristic for all the populations of Thymus glabrescens and T. pannonicus as well as for certain taxa belonging to T. praecox and T. pulegioides. Sesquiterpenes occurred in only two taxa of T. glabrescens, in each sample of T. praecox and in three taxa of T. pulegioides. Plant samples were analysed by random amplified polymorphic DNA (RAPD). The obtained dendrogram revealed high gene diversity. The 13 primers resulted 114 polymorphic RAPD bands, and the average percentage of polymorphism was 80.8%. The RAPD dendogram showed separation neither at interspecific nor at interpopulational levels. Therefore, further specific molecular studies involving more taxa are suggested. Partial correlation have been found between molecular and chemical assessments.
Phenoloids with allelopathic effect (juglone, ctaechin, tannin, gallic acid t-cinnamic acid, caffeic acid, coumarin, thymol, salicin in 1mM concentration) cannot be detected after the absorption from the acceptor plant (bean) by the applied selective analytical method (TLC densitometry). Their localisation can be determined by histochemical reagens (ferrichloride, potassium bichromate, sodium hydroxide). In the foliage leaves and excised bean plants they are present mainly in the parenchymatuos elements of the vascular tissue already on the 3rd day, at the beginning of wilting. Some substances (tropanes) out of the studied allelopathic alkaloids (atropine, scopolamine, belladonnin, tropine and caffeine) can be detected only in small amounts (7-8%) or only in traces in the leaf. Others (e.g. caffeine) accumulate in substantial amount (almost 200%) in their original form. Alkaloids,as well as phenoloids, can be detected in lesf tissue by histochemical methods (Dragendorff and Meyer reagents).
Authors:Gy. Horváth, L. Botz, B. Kocsis, É. Lemberkovics, and L. Gy. Szabó
Certain classes of bioactive compounds can be separated using planar chromatography. Some biological effects (e.g. antibacterial) of these compounds can be investigated directly by examining the growth of a test organism on a specially treated sorbent of thin layer chromatography (TLC). A special method of detection, direct bioautography, is suitable for studying the antimicrobial activity of plant extracts of natural origin by using TLC. Zones of inhibition are visualised by use of a dehydrogenase-activity-detecting, tetrazol-type reagent. Zones of inhibition appeared as pale spots separating well from the dark background. The antibacterial effect of the main essential oil components of some Thymus taxa, as well as that of two antibiotics (streptomycin sulphate and gentamycin) known and applied in practice was investigated against plant pathogenic bacteria. Results showed that thyme essential oil and its components inhibited the growth of test bacteria, but not so considerably as the antibiotics applied. Compositions of the essential oils were analysed by gas chromatography (GC). It could be verified that among the essential oil components, thymol and carvacrol had the strongest inhibitory effect.
Authors:Banu Kaskatepe, Serap Suzuk Yildiz, Merve Eylul Kiymaci, Ayse Nur Yazgan, Salih Cesur, and Sinem Aslan Erdem
Fachini-Queiroz , F. C. , Kummer , R. , Estevão-Silva , C. F. , Barros Carvalho , M. D. , Cunha , M. J. , Grespan , R. , Bersani-Amado , C. A. , Cuman , R. K. N. ( 2012 ) Effects of Thymol and Carvacrol, Constituents of Thymus vulgaris L
Authors:Éva Németh-Zámbori, Zsuzsanna Pluhár, Krisztina Szabó, Mahmoud Malekzadeh, Péter Radácsi, Katalin Inotai, Bonifác Komáromi, and Katarzyna Seidler-Lozykowska
Babei , K. , Majid , A. D. , Sanavi , M. , Jabari , R. ( 2010 ) Water deficit effect on morphology, prolin content and thymol percentage of thyme ( Thymus vulgaris L.) . Iran J. Med. Arom. Plants 2 , 239 – 251 .