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The chemical fate of the endogenous plant antioxidants carvacrol and thymol during oxidative stress

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Synopsis The major antioxidants present in the essential (volatile) oils of oregano ( Origanum vulgare , L.), summer savory ( Satureja hortensis , L.) and thyme ( Thymus vulgaris , L.) have been identified as carvacrol and thymol which have both been demonstrated to possess fungicidal and bactericidal properties. EPR spectra produced upon oxidation are inconsistent with the expected phenoxy free radicals (RO), but resemble those of galvinoxyl and anthronyl radicals. The EPR spectrum, in the case of carvacrol, is a pair of quintets with isotropic splittings, 0.325 and 0.080 millitesla (mT). ENDOR and TRIPLE resonance experiments have been performed and are indicative of the paramagnetic species being a substituted anthronyl. Further studies are being conducted to characterise these species and to investigate their potential roles during oxidative stress.

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... The potential of thyme extracts as sources of food preservatives and specifically as food antioxidants is being realized. 32,44 The oils extracted from leaves and flowers are used in perfumery and medicine. Thyme is believed to strengthen the immune system and thyme oil has been used in tonics to treat depression, colds and muscular pain. ...
... In addition to being potentially targeted for inhibition of E. coli in processed meat it can also be used as an antioxidant in meat. 32,44 The use of natural phenolic metabolites in vegetables, meats and seafood will enhance the potential for processing and preserving food and increase the marketability of excess food products into Asia and Europe where natural plant extracts are widely used and readily accepted compared to synthetic chemicals. Since thyme phenolics like thymol, carvacrol and rosmarinic acid have antioxidant properties, it could also be an excellent base for potential skin care products serving as UV protectants and cancer chemopreventive metabolites following clearly defined clinical studies. ...
... In addition to their antimicrobial properties, thymol and carvacrol have received attention as possible antioxidants. 16,32,44 Thus, these natural compounds may have a dual function in lipid-containing foods such as meats. In terms of food safety, the results of our work could identify an additional 'barrier' to exposure to food-borne pathogens by global consumers. ...
... The potential of thyme extracts as sources of food preservatives and specifically as food antioxidants is being realized. 32,44 The oils extracted from leaves and flowers are used in perfumery and medicine. Thyme is believed to strengthen the immune system and thyme oil has been used in tonics to treat depression, colds and muscular pain. ...
... In addition to being potentially targeted for inhibition of E. coli in processed meat it can also be used as an antioxidant in meat. 32,44 The use of natural phenolic metabolites in vegetables, meats and seafood will enhance the potential for processing and preserving food and increase the marketability of excess food products into Asia and Europe where natural plant extracts are widely used and readily accepted compared to synthetic chemicals. Since thyme phenolics like thymol, carvacrol and rosmarinic acid have antioxidant properties, it could also be an excellent base for potential skin care products serving as UV protectants and cancer chemopreventive metabolites following clearly defined clinical studies. ...
... In addition to their antimicrobial properties, thymol and carvacrol have received attention as possible antioxidants. 16,32,44 Thus, these natural compounds may have a dual function in lipid-containing foods such as meats. In terms of food safety, the results of our work could identify an additional 'barrier' to exposure to food-borne pathogens by global consumers. ...
Article
Infectious diseases transmitted by food have become a major public health concern in recent years. In the USA alone, there are an estimated 6-33 million cases each year. The list of responsible agents continues to grow. In the past 20 years some dozen new pathogens that are primarily food-borne have been identified. Fruits and vegetables, often from the global food market, have been added to the traditional vehicles of food-borne illness; that is, undercooked meat, poultry, seafood, or unpasteurized milk. Such products are minimally processed and have fewer barriers to microbial growth such as salt, sugar or preservatives. The evolution of the epidemiology of food-borne illness requires a rethinking of traditional, though still valid, solutions for their prevention. Among various strategies to prevent food-borne pathogens, use of dietary phytochemicals is promising. The major obstacle in the use of dietary phytochemical is the consistency of phytochemicals in different foods due to their natural genetic variation. We have developed a novel tissue-culture-based selection strategy to isolate elite phenolic phytochemical-producing clonal lines of species belonging to the family Lamiaceae. Among several species we have targeted elite clonal lines of thyme (Thymus vulgaris) and oregano (Origanum vulgare) against Escherichia coli and Clostridium perfrigens in fresh and processed meats. We are also evaluating high phenolic profile-containing clonal lines of basil (Ocimum basilicum) to inhibit gastric ulcer-causing Helicobacter pylori. Other elite lines of the members of the family Lamiaceae, rosemary (Rosmarinus officinalis) and salvia (Salvia officinalis) also hold promise against a wide range of food pathogens such as Salmonella species in poultry products and Vibrio species in seafood.
... Essential oils from thyme (Thymus vulgaris L.) have antioxidant properties, which may result from the presence of free radical scavengers in these oils (Farag et al., 1989;Deighton et al., 1993Deighton et al., , 1994Aeschbach et al., 1994). The antioxidant property of essential oils of thyme is specifically linked to the phenolic metabolites thymol and carvacrol (Aeshbach et al., 1994;Deighton et al., 1994;Madsen and Bartlesen, 1995). ...
... Essential oils from thyme (Thymus vulgaris L.) have antioxidant properties, which may result from the presence of free radical scavengers in these oils (Farag et al., 1989;Deighton et al., 1993Deighton et al., , 1994Aeschbach et al., 1994). The antioxidant property of essential oils of thyme is specifically linked to the phenolic metabolites thymol and carvacrol (Aeshbach et al., 1994;Deighton et al., 1994;Madsen and Bartlesen, 1995). In addition, these compounds have been shown to have bactericidal and fungicidal properties (Beuchat, 1976;Conner and Beuchat, 1984;Karapmar and Aktug, 1987;Akgul and Kiranc, 1988;Sharpiro et al., 1994;Curtis et al., 1996). ...
Article
A high phenolics-containing clonal line (T-12) of thyme (Thymus vulgaris L.) was isolated from a heterogeneous seed population by plant tissue culture techniques. This clonal line was isolated from among 10 clonal lines, with each originating from different genetically heterozygous, single-germinating seedlings. All clonal lines were generated via shoot organogenesis through adventitious bud proliferation from apex explants. Optimum shoot organogenesis was induced on Murashige and Skoog (MS) medium with benzyladenine (1 mg/L) as the growth hormone. Multiple shoots originating from apex explants of single heterozygous seedlings were further multiplied on the aforementioned benzyladenine-containing MS medium to subsequently generate a larger number of clonally identical plants. Shoots from each individual clonal line were inoculated with a novel Pseudomonas sp. Following growth on hormone-free MS medium for 25 days, total phenolics were determined spectrophotometrically. Using this approach, high phenolics-stimulated clonal line T-12 and moderate phenolics-stimulated clonal time T-16G were isolated. These clonal lines attained the higher level of phenolics following Pseudomonas inoculation and also had uninhibited shoot growth compared with the corresponding uninoculated control. Several low phenolics clonal lines, which had inhibited shoot growth in response to Pseudomonas sp., were also isolated. Thymol levels of uninoculated shoots of all clonal lines after 60 days of growth were also measured by gas chromatography−mass spectroscopy. The high-to-medium phenolics-containing clonal lines (T-12 and T-16G) had basal thymol levels in the range of 150 μg/g fresh weight (FW). The thymol levels of low phenolics-containing clonal lines were in the range 10−70 μg/g FW. This Pseudomonas sp.-mediated selection provides a potentially novel biotechnology based strategy to isolate high phenolics and thymol-containing clonal lines of thyme from a genetically heterogeneous population. Keywords: Biotechnology; clonal lines; micropropagation; phenolics; Pseudomonas sp.; thymol; Thymus vulgaris
... Essential oils from thyme (Thymus vulgaris L.) have antioxidant properties, which may result from the presence of free radical scavengers in these oils (Farag et al., 1989;Deighton et al., 1993Deighton et al., , 1994Aeschbach et al., 1994). The antioxidant property of essential oils of thyme is specifically linked to the phenolic metabolites thymol and carvacrol (Aeshbach et al., 1994;Deighton et al., 1994;Madsen and Bartlesen, 1995). ...
... Essential oils from thyme (Thymus vulgaris L.) have antioxidant properties, which may result from the presence of free radical scavengers in these oils (Farag et al., 1989;Deighton et al., 1993Deighton et al., , 1994Aeschbach et al., 1994). The antioxidant property of essential oils of thyme is specifically linked to the phenolic metabolites thymol and carvacrol (Aeshbach et al., 1994;Deighton et al., 1994;Madsen and Bartlesen, 1995). In addition, these compounds have been shown to have bactericidal and fungicidal properties (Beuchat, 1976;Conner and Beuchat, 1984;Karapmar and Aktug, 1987;Akgul and Kiranc, 1988;Sharpiro et al., 1994;Curtis et al., 1996). ...
Article
Plant phenolics are secondary plant products, sometimes synthesized as chemical defenses to microorganisms, and also serve as potential sources of food preservatives. In this study, we have investigated the extent of stimulation of total phenolics and rosmarinic acid (RA) levels in three in vitro shoot culture-based thyme clonal lines in response to a novel Pseudomonas spp. previously isolated from oregano tissue cultures. Clonal lines chosen for this study were the high phenolic line T-12 and the medium- and low-phenolic lines T-16G and M-3. Results indicate that different strains of Pseudomonas stimulated total phenolic levels and RA accumulation to varying degrees. Mucoid strain M4 elicited the highest levels of RA in clonal line T-12 on day 25. A moderate degree of RA stimulation in response to M4 was observed in clonal line M-3. Mucoid strain F elicited the highest total phenolic levels in T-12 on day 25. Nonmucoid strain NMA elicited stimulation of total phenolic compounds and RA to some degree only in clonal line T-16G. A 30 day time course analysis in line T-12 indicated that strains F and NMA elicited the highest phenolic levels. RA synthesis appeared to be stimulated in response to M4 at later stages of growth and reduced stimulation was apparent in response to F and NMA. The mechanical rigidity of T-12 shoots appeared to be highest in response to mucoid strain M4, indicating the possibility of increased lignin formation. This Pseudomonas-thyme clonal system provides a foundation to investigate the microbially-elicited stimulation of biosynthetic pathways leading to novel antimicrobials and antioxidants.
... In foods, the use of essential oils or their individual components, as potential natural preservatives has been reported in cheese [25], bakery products [26], and meat [27], although there is little evidence of a role for them in the control of fruit decay. Essential oils containing high amounts of thymol and carvacrol were reported to possess the highest antioxidant activity [28][29][30][31][32]. In addition, these compounds exhibit other bioactivities, for example, thymol has antiseptic, antibacterial, antifungal, antioxidative, and food preservative properties [33], while carvacrol possesses antifungal properties [34]. ...
Article
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Several postharvest diseases of table grapes (Vitis vinifera) occur during storage, and gray mold rot is a particularly severe disease because the causal agent, Botrytis cinerea, grows at temperatures as low as 0℃. Other postharvest diseases, such as those caused by Penicillium spp. and Aspergillus spp., also often lead to deterioration in the quality of table grapes after harvest. The use of plant essential oils such as thymol and linalool, to reduce postharvest diseases in several kinds of fruits, including table grapes and oranges, has received much attention in European countries. However, to the best of our knowledge there has been no report of the use of thymol fumigation to control gray mold in table grapes in Korea. Thymol (30 µg/mL) and linalool (120 µg/mL) significantly inhibited mycelial growth and conidia germination of B. cinerea. The occurrence rate of gray mold rot of B. cinerea and other unknown fungi was significantly reduced by fumigation with 30 µg/mL thymol in several table grape cultivars, such as Campbell early, Muscat Bailey A, Sheridan, and Geobong. In this study, fumigation with 30 µg/mL thymol, had no influence on the sugar content and hardness of grapes, but reduced fungal infection significantly. This suggests that 30 µg/mL thymol could be utilized to reduce deterioration of grapes due to gray mold and other fungal infections during long-term storage.
... hirtum), savory and thyme produced ESR spectra accounted for free radicals generated by phenolics, carvacrol and thymol. The conclusion was based on previously known antioxidant properties of these molecules (Deighton, Glidewell, Goodman, & Deans, 1994;Deighton et al., 1993 (Table 4). Among the four oregano extracts, the OH-AO 100°C was the most effective at scavenging superoxide anion free radicals. ...
... Antioxidant compounds have been shown to have a suppressive effect on the related soil-borne pathogen Sclerotium rolfsii and its sclerotial development (Georgiou, 1997;Abo Ellil, 1999;Georgiou et al., 2000aGeorgiou et al., ,b, 2003Georgiou and Petropoulou, 2001). In addition, essential oils have shown to possess antioxidant properties (Zygadlo et al., 1995;Baratta et al., 1998a,b;Ruberto and Baratta, 2000;Meral et al., 2002;Deighton et al., 2003). Thus, the monoterpenes could be capable of inhibiting development of S. cepivorum sclerotia and to modify lipid composition of its mycelia. ...
... Among the secondary metabolites, plant phenolics are important ingredients in several commercial applications as an antioxidant in food, dietary supplements, cosmetics, and pharmaceuticals. Such antioxidant activity has been demonstrated in the essential oil obtained from oregano (Origanum vulgare) in a number of studies (1,7,8,10,12,26,28). Yet, the use of oregano for antioxidant purposes has been limited owing to the inconsistent levels and types of phenolics that result from the genetic heterogeneity common among natural cross-pollinated plants (24). ...
Article
Oregano, Origanum vulgare, is a source of essential oils and phenolic metabolites, such as rosmarinic acid, which exhibits anti-oxidant and antimicrobial activity. This suggests that the plant material could be useful in food preservation, and in nutraceutical and cosmetic applications. Due to natural cross-pollination, however, oregano has substantial plant-to-plant variation and therefore a considerable genetic inconsistency in the type and level of phytochemicals produced. In this study, clonal lines developed from a population of heterozygous seeds using tissue culture were screened for desirable traits (multiple shoot formation and enhanced biomass, and rosmarinic acid and phenolic acid production) based on tolerance of the clonal lines to Pseudomonas and azetidine-2-carboxylate (A2C). Of the 20 clonal lines isolated, two over-expressed phenolic acids in response to both Pseudomonas and A2C.
... Plant phenolic compounds can be used as natural food ingredients such as antioxidants (Cuvelier et al. 1994;Deighton et al. 1994) and flavors (Giese 1994). Some of these phenolics such as rosmarinic acid (RA) also exhibit medicinal and antimicrobial properties (Englberger et al. 1988;Shapiro and Guggenheim 1994;Zaika 1988). ...
Article
Plant phenolic compounds such as rosmarinic acid exhibit antioxidant and antimicrobial activities and have potential as functional food ingredients. Our model has proposed that a cellular redox cycle linking pyroline-5-carboxylate and proline can stimulate the pentose phosphate, shikimate and phenylpropanoid pathways, and ultimately lead to an increase in phenolic synthesis, including rosmarinic acid (RA). In this study, the response of thyme shoot clones to proline and/or proline analogs was investigated through measurement of total phenolics, rosmarinic acid and proline levels, as well as glucose-6-phosphate dehydrogenase (G6PDH) and phenylalanine ammonia-lyase (PAL) activities. A genetically uniform, high phenolic-containing thyme shoot-based clonal line T-12 was used. Results indicate that supplementation of exogenous proline did not enhance total phenolic and rosmarinic acid content. Therefore, exogenous proline may not have stimulated the proline-linked pentose phosphate pathway. However, increases in proline, total phenolics and rosmarinic acid synthesis were observed following supplementation with the proline analogs, hydroxyproline and azetidine-2-carboxylate. These analogs through proline synthesis may have activated the pentose phosphate pathway and therefore the phenylpropanoid pathway by linking steps involved in NADP/NADPH interconversions. As a result, increases in total phenolic and rosmarinic acid levels were observed. This mode of regulation via proline synthesis-linked to pentose phosphate pathway may be important for synthesis of RA and its overexpression in elite thyme clonal lines for food and medicinal applications.
... Thymus species as well as many other aromatic plants biosynthesize remarkable amount of volatile compound referred as the essential oil; therefore chemical classification of such plants is based on the main essential oil components. Among the major compounds available in the oil, thymol and carvacrol were reported to possess the highest antioxidant activity [12][13][14][15]. In addition, these compounds exhibit other biological activities, e.g. ...
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Full-text available
This study was designed to examine the in vitro antimicrobial and antioxidant activities of the essential oil of T. boveii and T. hyemalis. According to the results of GC-EIMS analysis, essential oils were found rich in phenols and hydrocarbons. p-cymene, thymol and carvacrol were mainly found as the major compounds for the essential oils. Both plant species showed remarkable antioxidant activity in all test systems except chelating effect. In the case of antimicrobial activity, the oils showed remarkable growth inhibition against the tested microorganism except K. pneumoniae, P. aeruginosa, L. monocytogenes, P. fluorescens.
... Chemical polymorphism is characteristic to the species of Thymus; numerous chemotypes have been defined, such as carvacrol and thymol, a-terpineol, thujone, geraniol, linalool and others (Thompson, Manicacci, & Tarayre, 1998). Essential oils containing high amount of thymol and carvacrol were reported to possess the highest antioxidant activity (Aeschbach et al., 1994;Dapkevičius, Venskutonis, Van Beek, & Linssen, 1998;Deighton, Glidewell, Deans, & Goodman, 1994;Farag, Badei, & ElBaroty, 1989). In addition, these compounds exhibit other bioactivities, e.g. ...
Article
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Radical scavenging and antibacterial properties of large thyme extracts isolated from five chemotypes of Thymus pulegioides L. growing wild in Lithuania were studied. The chemotypes were defined according to the main essential oil components: linalool (L), geranial/geraniol/neral (G/G/N), thymol (T), carvacrol/γ-terpinene/p-cymene (C/γT/pC) and thymol/carvacrol/γ-terpinene/p-cymene (T/C/γT/pC). The contents of phenolic compounds, flavonoids and flavonols were determined. It was found that the extracts of phenolic chemotypes containing remarkable concentrations of thymol and/or carvacrol were stronger DPPH and ABTS free radical scavengers in the model systems. The antibacterial activity of the extracts depended on the plant chemotype, extract preparation, solvent used and finally the sensitivity of bacteria. Bacillus cereus, Micrococcus luteus, Staphylococcus epidermidis and Staphylococcus aureus were the most sensitive to the all extracts applied, whereas Escherichia coli, Salmonella typhimurium and Enterobacter aerogenes remained resistant.
... Thymus species as well as many other aromatic plants biosynthesize remarkable amount of volatile compound referred as the essential oil, therefore chemical classification of such plants is based on the main essential oil components. Among the major compounds available in the oil, thymol and carvacrol were reported the possess the highest antioxidant activity (Dapkevicius et al., 1998;Aeschbach et al., 1994;Deighton et al., 1994;Farag et al., 1989). In addition, these compounds exhibit other biological activities, e.g. ...
Article
This study is designed to examine the chemical composition and in vitro antioxidant activity of the hydrodistillated essential oil and various extracts obtained from Thymus longicaulis subsp. longicaulis var. longicaulis. GC and GC-MS analysis of the essential oil were resulted in determination 22 different compounds, representing 99.61% of total oil. gamma-terpinene, thymol and p-cymene were determined as the major compounds of the oil (27.80, 27.65 and 19.38%, respectively). Antioxidant activities of the samples were determined by four different test systems namely beta-carotene/linoleic acid, DPPH, reducing power and chelating effect. Essential oil showed the highest antioxidant activity in beta-carotene/linoleic acid system among the experiments examined. In the case of other test systems, in general, methanol and water extracts exhibited the strongest activity profiles. Especially, reducing power of water extract was found superior than those of synthetic antioxidants. As well as the antioxidant activities of the extracts, they were evaluated in terms of their total phenolic and flavonoid contents. Hexane and water extracts were found to be rich-in phenolics. However, flavonoids were determined in the highest level in methanol extract.
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This study examines the anatomical structure of the glandular apparatus in Satureja cuneifolia Ten., as well as the chemical composition of the essential oil derived from it. Leaves were collected from a population in Dalmatia (Croatia). Anatomically, the glandular scales feature a unicellular base, a unicellular stalk and a 12-celled head. Each glandular apparatus was observed to be surrounded by epidermal cells. Qualitative and quantitative GC-MS analysis of the essential oil showed that linalool, carvacrol and p-cymene were its main constituents.
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The composition of the essential oil of Origanum vulgare L. (Lamiaceae) from Macedonia was examined by analytical GC-FID and GC-MS techniques. Three different populations of the taxa were investigated and compared to commercial sample of Origani herba. More than fifty components were separated in the oils, twenty of them were identified, representing 68.6-91.5% of the whole oils. Three wildly growing Origanum specimens contained much lower quantities of essential oils (0.1-0.2%) in comparison to the commercial sample (3.1%). The essential oils from three samples of wild origano were non-phenolic, without carvacrol and with traces of thymol (0.1-1.7%). These oils contained α-pinene (40.0-67.5%) and β-caryophyllene (7.4-26.6%) as major constituents. The commercial sample contained higher amount of α- pinene, too, but the most important constituents of the oil were thymol (31.1%) and carvacrol (36.4%).
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Antioxidant activity of five Thymus L. (Lamiaceae) species from Macedonian flora was investigated. Ether and ethyl acetate extracts from overgrown herbal parts were prepared and added to the antioxidant and peroxide-free lard. The Wheeler method was used to monitor the oxidative stability of lipids. The progress of oxidation was observed by measuring the peroxide value. It was found that all of the investigated taxa showed some antioxidant activity, in poor dependence on their total flavonoid content. The ethyl acetate extract of Thymus moesiacus was found to be the most active.
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Satureja (Lamiaceae) species are used as flavoring compounds in food, pharmaceutical, and cosmetic industries because of its sweetness and simple cultivation characteristics. They have traditionally been used as muscle pain relievers, tonic, and carminative agents to treat stomach and intestinal disorders such as cramps, nausea, indigestion, and diarrhea, due to their considerable phytochemical characteristics. This review evaluates some information published since 1989 on Satureja genus from a systematic perspective in terms of its pharmacological and phytochemical characteristics. Web of Science, PubMed, Scopus, and Google Scholar databases were searched up to March 2014. "Satureja" was used as a research term without narrowing or limiting research elements. After obtaining all reports from database (a total number is about 637), the papers were carefully analyzed in order to find data related to the topic of this review. In this review, 453 reports were used which were published between 1989 and 2014. The study was compiled into two sections (Pharmacology and Phytochemistry). In the pharmacology section, more than 50 different activities were studied. In the second section, in addition to other compounds and inorganic substances, volatiles, phenolic acids, and flavonoids were discussed. According to our contemporary information, Satureja species have been evaluated for their wide range of biological activities. However, a small part of these studies have been carried out on the active principles. Therefore, in the future, more studies should be carried out to identify responsible phytochemicals for the various activities.
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It has been reported that oxidative stress plays a vital role in nickel-induced biochemical and molecular alterations. The effects of thyme on the cytotoxicity and genotoxicity induced by nickel chloride were examined with respect to the DNA fragmentation in liver and testis, micronuclei formation, intracellular glutathione and alteration in gene expression. The obtained data from this study revealed that treatment of mice with NiCl2 (20 mg/kg) for two consecutive days, exhibited significantly (p≤0.05) bone marrow cytotoxicity and a server reduction in number of PCEs was detected, in addition a significant (p≤0.05) induction in micronucleated PCEs (Mn-PCEs) (28.2 ± 0.75) compared with control group (3.0 ± 0.48). Further more, NiCl2 significantly depleted intracellular glutathione (GSH) levels in hepatic and testicular tissues by 27 & 31.5 % below that of control group and led to apoptotic changes in both tissues as evidenced by DNA fragmentation (21.5% compared to 8.5% in liver & 24.6% compared to 5.0% in testis) as measured by diphenylamine assay. However, pretreatment with thyme oil, significantly (P≤0.05) increased the number of PCEs and decreased the frequencies of Mn-PCEs (10 ± 0.48).The GSH levels were significantly increased in group pretreated with thyme in hepatic and testicular tissues (34.8% and 29.75 % above control values). Moreover, DNA fragmentations were significantly reduced reached to 62.7% in testis and 65.2% in liver when mice pretreated with thyme. Hepatic mRNA levels for Fas, the apoptosis-promoting gene Bax, and TNFά, were up regulated following NiCl2 exposures in mice as compared to vehicle controls. In summary, the results suggest that the chemo preventive role of thyme against nickel chloride-induced testicular and liver genotoxicity may be due to its intrinsic antioxidant property and it exhibits a hepatoprotective effect, the mechanism of which may involve thyme anti-inflammatory and antiapoptotic effects. [Sabah Abdulaziz Linjawi. Thyme (Thymus capitatus) regulating altered hepatic mRNA expression of apoptotic genes during Nickel Chloride exposure.
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We are applying a dynamic systems biology approach to the development of several phenolic phytochemicals in food-grade plants as ingredients for functional food applications. Phenolic antioxidant phytochemicals from food-grade plants will be an important part of a healthy diet in a global population that is projected to reach 9 billion in the next 50 years. Such phytochemicals are being targeted for designing conventional foods with added health benefits (functional foods). Such value-added foods are needed for dietary support to manage major oxidation-linked diseases, such as diabetes, cardiovascular disease, arthritis, cognition diseases and cancer. Plants produce phenolic metabolites as a part of growth, developmental and stress-adaptation response. These stress and developmental-modulated phenolic phytochemicals can be targeted for the design of functional foods. In order to design consistent food-grade phytochemical profiles for safety and clinical relevancy, novel tissue culture and bioprocessing technologies have been developed. The strategy for designing these phenolic phytochemicals is based on the model that phenolic metabolites in plants are efficiently produced through an alternative mode of metabolism that links proline synthesis to activity of the pentose–phosphate pathway. Using the proline-linked pentose–phosphate pathway model, techniques have been developed to isolate high phenolic clonal lines of food-grade plants from single heterozygous seeds. Further, using the same model, elicitation concepts and techniques have been applied to over-produce phenolic metabolites in seeds and sprouts. In both clonal and seed sprout systems, exogenous treatment of phenolic phytochemicals from a non-target species elicited endogenous stimulation of phenolic synthesis and, potentially, an antioxidant response. From these investigations, a hypothetical model has been proposed in which the proline-linked pentose–phosphate pathway is critical for modulating protective antioxidant response pathways in diverse biological systems, including humans. This model, when confirmed precisely, may provide a mechanism for understanding the mode of action of phenolic phytochemicals in modulating antioxidant pathways in relation to human health. An understanding of the interconnection of the proline-linked pentose–phosphate pathway and antioxidant response pathway can provide dietary and nutritional mechanisms as well as new strategies to manage oxidation-linked diseases through improvement of host physiological response. In this review we have focused on clonal herbs, fava bean sprouts and cranberry bioprocessing as 3 model systems for understanding biosynthesis of phenolic metabolites for functional food application.
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The total phenol content, antioxidant and pro-oxidant activities of deodourised, water-soluble aniseed, basil, caraway, cardamon, fennel, ginger, juniper, laurel and parsley extracts were estimated using a number of in vitro assays. The laurel and basil extracts contained the highest phenol content of 107.3±1.3 GAE [mg gallic acid equivalents/g (dry wt.) extract] and 98.5±1.4 GAE, respectively, whilst the ginger extract contained the lowest content at 14.9±0.9 GAE. Juniper, laurel and basil extracts were consistently better than the other extracts in terms of iron(III) reducing activity, inhibition of β-carotene-linoleate thermal co-oxidation and N,N-dimethyl-p-phenylenediamine and hydroxyl radical scavenging assays. Potential pro-oxidant activities of the extracts were assessed using both DNA and bovine serum albumin (BSA) as substrates. None of the extracts were capable of stimulating hydroxyl-mediated DNA fragmentation; however, the extracts could be categorised in the protein oxidation assay as extracts with (i) no significant (p>0.05) effect, (ii) a significant (p
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Assay of flavonoids in extracts of seven Thymus L. (Lamiaceae) species from Macedonia including identification and quantification was performed. Extracts obtained after hydrolysis of air dried samples (A1) were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Luteolin and apigenin were identified in comparison to authentic standard substances. The content of total flavonoids in plant samples determined by UV-Vis spectrometry (with AlCl3) ranged from 0.05-0.13 %. Two other extracts were prepared by extraction with a mixture of ethanol:water (7:3, V/V), evaporation until only water remained and extraction first with diethylether (A2) and secondly with ethyl acetate (A3). The content of flavonoids in diethyl-ether and ethyl acetate extracts ranged from 52.5-244.4 mg·ml-1 and 48.7 -117.5 mg·ml-1, respectively. For quantification of luteolin and total flavonoids the HPLC method was applied, using reverse phase column C18, mobile phase consisting of 5% acetic acid and methanol in gradient elution mode and column temperature set to 40 oC. The content of luteolin in the plant samples ranged from 0.23-0.48 % (m/m), while the content of total flavonoids was found to be 0.26-0.52 %.
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Essential oil composition of Thymus tosevii ssp . tosevii var. longifrons growing wild in Macedonia was examined by the GC-FID and GC-MS methods. Four different types of essential oil were found, one with almost equ al 1Faculty of Pharmacy contents of thymol and carvacrol, two others with only one of the phenols dominating (thymol or carvacrol) and the last one was a nonphenolic type of the oil. In most of the samples, phenols were the most abundant components followed by p-cymene and y-terpinene. The samples containing phenols only in traces, contained geraniol, linalool and geranyl acetate as main oil components.
Article
Using GC and GC-MS techniques, two different varieties of Thymus longidens Vel. (var. lanicaulis and var. dassareticus) have been examined on essential oils composition. Big differences in oil composition were noticed. Var. lanicaulis conlained35.65 41.56/33.66% of thymol/carvacrol, 11.96-31.52% of geraniol and 9.46-9.66 % of terpynilacetate as main components while the essential oil from var, dassareticus contained very low amounts of thymol (3.95%) and carvacrol (1.98 %) and higher quantities of Iinalool (14.81 %), geraniol (14.49%), a.-terpineol (15.62%) and terpynil acetate (16.23%) as major constituents. Lemon like odor of second oil was noticed, originating from presence of ecitral (5.56%) and citral (3.60%) that were determined. First analyzed taxa belongs to the phenol type while the second one is lemon type of genera Thymus L.
Article
Assay of flavone aglycones in extracts of Origanum vulgare from Macedonia including identification and isolation is performed. Hydrolyzed extracts were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Three aglycones were identified and then isolated by column chromatography and TLC. Further TLC, HPLC, and UV/VIS spectrophotometric analysis showed that the isolated compounds are luteolin (the most abundant), apigenin, and diosmetin. A new and rapid HPLC method was developed only for determination of the content of luteolin, which can serve as an appropriate criterion for evaluation of the flavonoid content in the drug. The accuracy of the method was proven by the method of standard additions, which gave satisfactory values for the recovery (98.2–100.3 %). The quantity of luteolin found in the drug ranged from 0.40–0.50 % (m/m).
Article
Synopsis Plants have evolved a multiplicity of defence mechanisms against pathogen attack. Their modes of action may be to (i) kill the pathogen directly, (ii) block the action of enzymes required for infection, or (iii) erect barriers to pathogen growth. Some of these reactions proceed via free radical intermediates and make use of either atmospheric oxygen or reactive oxygen species. This paper reviews the various types of reaction involving oxygen-derived free radicals that are initiated in plant tissue when it is invaded by pathogenic organisms. Both the production of free radicals by plants in defensive processes and the utilisation of free radicals by pathogens in offensive reactions are considered and particular attention is given to the use of electron paramagnetic resonance (EPR) spectroscopy for the direct observation of such free radical reactions.
Article
Monoterpenes have antifungal activity on pathogenic fungi. The purpose of this study was to examine the effect of seven monoterpenes on phospholipid and sterol composition of Sclerotium cepivorum Berk as well as lipid peroxidation of mycelia and sclerotia development. Most of the monoterpenes increased the ergosterol content with a consequent diminution in the phospholipid/sterol ratio. This ratio was significantly decreased by the thymol treatment. When the fungus was grown in the presence of thymol or borneol, the saturated fatty acid content and the lipid peroxides were increased, concomitant with an increase of the sclerotial diameter. These results indicate that thymol and borneol may be promoting generation of lipid peroxides. Sclerotial differentiation was retarded mainly by camphor, 1,8-cineole, linalool and menthol.
Article
Electron paramagnetic resonance (EPR) spectroscopy is used to measure directly the generation of free radicals during a simulation of the mastication process. This involves the gentle grinding of the food product in the presence of a spin trap, a molecule which reacts selectively with unstable free radicals to generate (more) stable radical adducts, which can then be characterised. With mushrooms of the Agaricus family, adducts consistent with a carbon-centred radical are seen with a wide range of spin traps and this radical has been confirmed as 4-(hydroxymethyl)phenyl. In plant tissues that are rich in ascorbic acid, this molecule competes successfully with spin traps for the free radicals and the (monodehydro)ascorbate radical, formed by the 1-electron oxidation of ascorbic acid, is seen in the EPR spectra. However, with >50% of the plant tissue samples studied in the present experiment, free radicals resulting from oxidation of the spin traps were observed. The formation of such molecules, for which oxygen was found to be necessary, requires the existence of powerful oxidation processes as the plant tissue is broken down. Such pro-oxidant behaviour is contrary to the popular assumption that the beneficial effects of uncooked plant tissues are the result of their high levels of anti-oxidant molecules.
Article
The antifungal effects of 22 essential oils from Turkish spices, herbs and citrus peel on four foodborne moulds were evaluated for fungistatic and fungicidal activity. The most active oils were wild thyme (Thymus rariflorus L) and thyme (Thymus serpyllum L). Parsley (Penloselinum sativum Hoffin) and savory (Satureja hortensis L) oils were found to be the least active oils. Rhizopus sp displayed the greatest tolerance, and the most sensitive mould was Penicillium chrysogenum. Prolonged incubations reduced the fungistatic and fungicidal effects of oils. It was concluded that some oils may be useful as mould inhibitors at food additive levels.
Article
The formation of stable free radicals upon reaction of the essential oils of 10 plant species with ultraviolet radiation and the superoxide radical anion, O2−, has been investigated by electron paramagnetic resonance (EPR) spectroscopy. Only the oils from oregano, summer savory and thyme produced EPR spectra and the results can be accounted for in terms of free radicals produced by the closely related phenolics, carvacrol and thymol. These observations are interpreted in terms of the known antioxidant properties of these molecules.
Article
The antifungal activity of several components of essential oils were evaluated using a paper-disk method. The substances investigated are structurally related to eugenol. Equimolar amounts were tested on more than ten fungal strains known to contaminate food. Iso-eugenol, cinnamaldehyde, carvacrol, eugenol and thymol revealed the strongest antifungal activity. The most resistant strain appeared to bePenicillium verrucosum var.cyclopium, and the most sensitive wasP. viridicatum. Some of the structural effects were considered, including a free hydroxyl group[Die antimykotische Wirkung mehrerer Komponenten von therischen len wurde mit einem Agar-Diffusionstest bestimmt. Die untersuchten Substanzen sind strukturell mit Eugenol verwandt. quimolare Mengen wurden an mehr als zehn Schimmelpilzstmmen getestet, von denen bekannt ist, da sie Lebensmittel kontaminieren. Iso-Eugenol, Zimtaldehyd, Carvacrol, Eugenol und Thymol zeigten die strkste antimykotische Wirkung. Der unempfindlichste Stamm war einPenicillium verrucosum var.cyclopium, whrend einP. viridicatum den sensibelsten darstellte. Einige Struktur-Wirkungsbeziehungen konnten in Betracht gezogen werden. Eine aktive Konfiguration bei phenolischen Verbindungen zur Entfaltung antimykotischer Wirkung scheint die freie Hydroxylgruppe in Verbindung mit einem Aklkylsubstituenten zu sein.