Characterization of the essential oil volatiles of Satureja thymbra and Satureja parnassica: Influence of harvesting time and antimicrobial activity

Seasonal variation in chemical composition of essential oils obtained from Satureja parnassica subsp. parnassica Heldr. & Sart ex Boiss. and Satureja thymbra L. was determined by GC and GC-MS analysis. The in vitro antibacterial activities of these essential oils were evaluated at two different initial levels against two common foodborne bacteria. Their minimum inhibitory concentration (MIC) and noninhibitory concentration (NIC) values were determined via an innovative automated technique, which was applied on a Malthus apparatus combining the conductance measurements with the common dilution method. The essential oil concentration fluctuated greatly during the period examined and established that the Satureja oils obtained during the flowering period were the most potent, exhibiting the lowest MIC values and retaining remarkable bactericidal properties. Thus, they represent an inexpensive source of natural antibacterial substances that exhibit potential for use in food systems to prevent the growth of foodborne bacteria and to extend the shelf life of the processed food. © 2006 American Chemical Society

Insecticidal Efficacy of Silica Gel With Juniperus oxycedrus ssp oxycedrus (Pinales: Cupressaceae) Essential Oil Against Sitophilus oryzae (Coleoptera: Curculionidae) and Tribolium confusum (Coleoptera: Tenebrionidae)

Laboratory bioassays were carried out to evaluate the effect of silica gel enhanced with the essential oil (EO) of Juniperus oxycedrus L. ssp. oxycedrus (Pinales: Cupressaceae) (derived from berry specimens from Greece) against adults of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae). For that purpose, a dry mixture consisting of 500 mg of silica gel that had absorbed 2.18 mg of EO (total weight: 502.18 mg) was tested at three doses; 0.125, 0.250, and 0.5 g/kg of wheat, corresponding to 125, 250, and 500 ppm, respectively, and silica gel alone at 0.5 g/kg of wheat corresponding to 500 ppm, at different exposure intervals (24 and 48 h and 7 and 14 d for S. oryzae; 24 and 48 h and 7, 14, and 21 d for T. confusum). The chemical content of the specific EO was determined by gas chromatography (GC)-mass spectrometry (MS) analyses indicating the presence of 31 constituents with myrcene and germacrene-D being the predominant compounds. The bioactivity results for S. oryzae indicated that 48 h of exposure in wheat resulted in an 82% mortality for treatment with 500 ppm of the enhanced silica gel. For 7 d of exposure, 100 and 98% of S. oryzae adults died when they were treated with 500 and 250 ppm of enhanced silica gel, respectively. At 14 d of exposure, all adults died both at 250 and 500 ppm of enhanced silica gel. At 48 h, 7 and 14 d of exposure significantly less S. oryzae adults died in wheat treated with silica gel alone than at 250 or 500 ppm of enhanced silica gel. In the case of T. confusum, at 7 d of exposure, mortality in wheat treated with silica gel only was significantly higher in comparison to the other treatments. At the 14 d of exposure mortality in wheat treated with 500 ppm of silica gel alone was significantly higher than 125 and 250 ppm of the enhanced silica gel. Similar trends were also noted at 21 d of exposure, indicating that there is no enhancement effect from the addition of the EO. Results herein suggest that the simultaneous use of silica gel and J. oxycedrus ssp. oxycedrus EO enhances significantly its activity against S. oryzae

“Gold” Pressed Essential Oil: An Essay on the Volatile Fragment from Citrus Juice Industry By-Products Chemistry and Bioactivity

Present essay explores the potentials of Citrus juice industry’s by-products as alternative bioactive natural products resources. Four crude Cold Pressed Essential Oils (CPEOs), derived from orange, lemon, grapefruit, and mandarin, were studied. All CPEOs were subjected to water distillation, in order to obtain the volatile fragment, which was further fractionated with respect to distillation period in two parts, concluding to eight samples. These samples along with the four original CPEOs were assessed in relation to their phytochemical content and their repellent and larvicidal properties against Asian Tiger Mosquito. The volatiles recovery rates ranged from 74% to 88% of the CPEO. Limonene presented a significant increase in all samples ranging from 8% to 52% of the respective CPEO’s content and peaked in mandarin’s 2nd volatile fragment which comprised 97% of the essential oil. The refinement process presented clear impacts on both bioassays: a significant increase in larvicidal potency was observed, annotated best by the improvement by 1100% and 1300% of the grapefruit volatile fractions; repellence testing provided only one significant result, the decrease of landings by 50% as a response to mandarin’s second volatile fraction. The applied methodology thus may be considered for the improvement of Citrus juice industry’s by-products chemistry and bioactivity

Essential Oil Coating: Mediterranean Culinary Plants as Grain Protectants against Larvae and Adults of <i>Tribolium castaneum</i> and <i>Trogoderma granarium</i>

Postharvest agricultural losses constitute a major food security risk. In contrast, postharvest protection is strongly linked with food safety. The present study aims to develop novel postharvest protection tools through a bioprospecting protocol utilizing edible essential oils (EOs) as grain coatings. For this purpose, six Mediterranean culinary plants were selected for evaluation. The EOs of juniper, Juniperus phoenicea L. (Pinales: Cupressaceae), marjoram, Origanum majorana L. (Lamiales: Lamiaceae), oregano, Origanum vulgare ssp. hirtum (Link) A.Terracc. (Lamiales: Lamiaceae), bay laurel, Laurus nobilis L. (Laurales: Lauraceae) and tarhan, Echinophora tenuifolia ssp. sibthorpiana (Guss.) Tutin (Apiales: Apiaceae) were retrieved through steam distillation, while lemon, Citrus limon (L.) Osbeck (Sapindales: Rutaceae) EO was retrieved through cold press extraction. All EOs were formulated to microemulsions (MEs) and applied uniformly as a coating on wheat against larvae and adults of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Trogoderma granarium Everts (Coleoptera: Dermestidae). All EO-based MEs have been evaluated for the first time as grain coatings. They caused moderate to high mortality to T. castaneum larvae (67.8–93.3% 14 days post-exposure) and T. granarium adults (70.0–87.8% after 7 days of exposure). Citrus limon, O. majorana and E. tenuifolia ssp. sibthorpiana EO-based MEs were the most efficient against T. castaneum larvae, by exhibiting 93.3%, 91.1% and 90.0% mortality 14 days post-exposure, respectively. Origanum majorana, L. nobilis and J. phoenicea EO-based MEs were the most efficient against T. granarium adults, exhibiting 87.8%, 84.4% and 83.3% mortality after 7 days of exposure, respectively. These results indicate that EO-based ME coating is a potent tool against the tested postharvest pests

Effect of a Carotenoid Extract from <i>Citrus reticulata</i> By-Products on the Immune-Oxidative Status of Broilers

Although carotenoids generally possess antimicrobial and antioxidant properties, the in vivo synergistic action of carotenoid blends derived from plant-based by-products has not been thoroughly studied. Therefore, the carotenoid characterization and antimicrobial potential of Citrus reticulata extract as well as the impact of this carotenoid-rich extract (CCE) dietary supplementation on the performance, meat quality, and immune-oxidative status of broiler chickens were determined. One hundred and twenty one-day-old hatched chicks (Ross 308) were allocated to two dietary groups, with four replicate pens of 15 birds each. Birds were fed either a basal diet (CON) or the basal diet supplemented with 0.1% CCE (25 mg carotenoid extract included in 1 g of soluble starch) for 42 d. β-Cryptoxanthin, β-Carotene, Zeaxanthin, and Lutein were the prevailing carotenoid compounds in the Citrus reticulata extract. The CCE feed additive exerted inhibitory properties against both Gram-positive (Staphylococcus aureus) and negative (Klebsiella oxytoca, Escherichia coli, and Salmonella typhimurium) bacteria. Both the broiler performance and meat quality did not substantially differ, while the breast muscle malondialdehyde (MDA) concentration tended to decrease (p = 0.070) in the CCE-fed broilers. The inclusion of CCE decreased the alanine aminotransferase and MDA concentration, and the activity of glutathione peroxidase, while the activity of superoxide dismutase was increased in the blood. Catalase and NADPH oxidase 2 relative transcript levels were significantly downregulated in the livers of the CCE-fed broilers. Additionally, Interleukin 1β and tumor necrosis factor (TNF) relative transcript levels were downregulated in the livers of the CCE- fed broilers, while TNF and interferon γ (IFNG) tended to decrease in the spleens and bursa of Fabricius, respectively. The present study provided new insights regarding the beneficial properties of carotenoids contained in Citrus reticulata in broilers’ immune-oxidative status. These promising outcomes could be the basis for further research under field conditions

Larvicidal, molluscicidal and nematicidal activities of essential oils and compounds from Foeniculum vulgare

Plant-based products, namely essential oils (EOs), are environmentally friendly alternatives for the control of disease vectors, hosts and/or parasites. Here, we studied the general toxicity and biopesticidal potential of EOs and phenylpropanoids from Foeniculum vulgare var. vulgare (bitter fennel), a perennial plant well adapted to temperate climates. EO/compound toxicity was tested against a freshwater snail and potential intermediate host of Fasciola hepatica (Radix peregra), a mosquito and former European malaria vector (Anopheles atroparvus) and one of the most damaging plant-parasitic nematodes, the root-knot nematode (Meloidogyne javanica). Lethal concentrations (LC50; LC90) of EOs (infrutescences/stems with leaves) and compounds were calculated by probit analysis. All displayed noteworthy activity against R. peregra adults (LC50 21-39 A mu g ml(-1)) and A. atroparvus larvae (LC50 16-56 A mu g ml(-1)). trans-Anethole revealed acute nematicidal activity after 24 and 48 h (LC50 310 and 249 A mu g ml(-1), respectively), and estragole (1,000 A mu g ml(-1)) showed some effectiveness against M. javanica hatching and juveniles after 15 days. Plant and EO yields were determined to evaluate the bitter fennel productivity. The chemical composition of the EOs was analyzed by gas chromatography coupled to mass spectrometry. EOs extracted from whole plants, infrutescences and stems with leaves were characterized by estragole-dominant profiles (28-65 %), considerable amounts of phellandrene (10-34 %) and fenchone (6-16 %), and minor trans-anethole contents (1-4 %). Although additional toxicological studies against nontarget organisms are required, our study demonstrates that bitter fennel is a productive source of molluscicides and larvicides, and thus a potential sustainable biological agent to control particular host species, namely freshwater snails and mosquitoes.We would like to thank Jose Ferreira and Diara Rocha from the IHMT for the mosquito colony maintenance and larvae production and collaborators from the Nematology Laboratory of the University of Coimbra for kindly providing the nematode isolate. The authors are grateful to Susana Chaves for improving the use of English in the manuscript. This research was supported by FEDER through POFC-COMPETE and by Portuguese funds through the projects (PIDDAC)-PEst-OE/BIA/UI4050/2014 and PEst-OE/AGR/UI4033/2014. R.M. Sousa was supported by the Portuguese Foundation for Science and Technology (FCT) through a PhD grant (SFRH/BD/66041/2009).info:eu-repo/semantics/publishedVersio