Doses Of Essential Oil Research Articles

Protective Effect of Lemon Essential Oil and Its Major Active Component, D-Limonene, on Intestinal Injury and Inflammation of E. coli-Challenged Mice.

Inflammatory diseases are a major threat to public health. Natural plant essential oils (EOs) possess anti-inflammatory and anti-oxidative activities. The objective of this study was to investigate the anti-inflammatory effect and mode of action of lemon essential oil (LEO), and its main active component, d-limonene, with different doses on intestinal inflammation of mice. Sixty-four 5-week-old male balb/c mice weighing 22.0 ± 1.5 g were randomly assigned into one of 8 treatments (n = 8/treatment), including normal saline group (NS), Escherichia coli (E. coli) group, and either LEO and d-limonene essential oil (DEO) group supplemented at 300, 600, and 1,200 mg/kg of BW, respectively. After the pre-feeding period, the mice were fasted for 12 h, the mice in the NS group and the E. coli group were gavaged with normal saline, and the mice in the LEO group and DEO group were gavaged with respective dose of EOs for 1 week. One hour after the end of gavage on the 7th day, except that the mice in the normal saline group were intraperitoneally injected with normal saline, the mice in the other groups were intraperitoneally injected with the same concentration of E. coli (108 cfu/ml, 0.15 ml per mouse). The antioxidant indexes were measured including superoxide dismutase (SOD), malondialdehyde (MDA), and myeloperoxidase (MPO) in plasma obtained by taking blood from mouse eyeballs. The inflammatory indexes were measured including interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor alpha (TNF-α) in plasma. The tight junction protein indicators were tested include zona occludens 1 protein (ZO-1), occludin and claudin in mouse duodenum. We found that all of the above indexes for E. coli group were different (P< 0.05) with the NS group. The interaction of EO and dose (E × D) were significant (P < 0.01) for all of the indexes. In addition, LEO at 300 mg/kg BW and DEO at 600 mg/kg BW had better antioxidant and anti-inflammation activity on the infected mice, which reduced (P < 0.05) the plasma concentrations of MDA, MPO, TNF-α, IL-1β, and IL-6, but increased (P < 0.01) the concentrations of SOD. Hematoxylin-eosin (H&E) staining of duodenum observation showed that LEO and DEO reduced inflammatory cell infiltration and maintain the orderly arrangement of epithelial cells. Moreover, supplementation of LEO at 600 mg/kg and DEO at 300 mg/kg BW alleviated (P < 0.05) intestinal barrier injury for increasing the relative expression of ZO-1, occludin and claudin mRNA in mice duodenum. These results showed that the pre-treatment with LEO and DEO had protection of intestinal tissue and inflammation in E. coli infected mice. Both LEO and DEO exhibited activity of antioxidant, anti-inflammatory and alleviating intestinal injury, whereas, compared with DEO, LEO can be active at a lower dosage. Furthermore, as the main active component of LEO, the d-limonene appeared to play not only the major role, but also the joint action with other active components of LEO.

Efficacy of cumin ( Cuminum cyminum ) and lavender ( Lavandula angustifolia ) essential oils as anaesthesics in common carp ( Cyprinus carpio L.1758)

In this study, anaesthetic effects of cumin and lavender essential oils by comparing with clove oil were determined on common carp. Fish (mean weight of 10 g) were exposed to nine concentrations of essential oils (5–500 mg L−1). Anaesthesia induction, recovery times and mean lethal dose of essential oils (10 min LC50 concentration) were evaluated separately for each fish. In addition, histopathological effects of essential oils on the fish tissues including hepatopancreas, gill and skin were investigated. The results showed that when the dose of essential oils increased, the time to anaesthesia induction was shortened and the time to recovery from anaesthesia was prolonged. Cumin essential oil at 300 mg L−1 dose and lavender oil at 400 mg L−1 dose on common carp showed similar anaesthetic effects (sedative and deep anaesthesia) to clove oil (p > .05). At these concentrations, sedative (Stage 2) and deep anaesthesia (Stage 4) induction times were 105 and 187.5 s for cumin and 94 and 194 s for lavender respectively. Recovery times at these concentrations were 415 s for cumin and 477.5 s for lavender. Mean lethal dose of essential oils for carp were found as 450 mg L−1 for cumin oil and 500 mg L−1 for lavender oil. Histopathological examination revealed no lesion in gill, skin and hepatopancreas in essential oils group. In the light of these findings, it was determined that lavender and cumin oils can be used as effective and safe anaesthetic in common carp.

Evaluation of oregano (Origanum vulgare) essential oil supplementation on growth performance, digestive enzymes, intestinal histomorphology and gut microbiota of Black Sea salmon, Salmo labrax

Abstract This study aimed to determine the effect of dietary oregano (Origanum vulgare) essential oil (EO) on the growth performance, digestive enzyme activity, intestinal histomorphology, and intestinal microbiota of the Black Sea salmon juvenile (Salmo labrax). Fish were fed diets different levels of oregano EO such as 50, 100, 200, and 400 mg kg−1. For this purpose, a total of 675 fish were distributed randomly in triplicate into 5 experiment groups in 15 experiment tanks. Fish with average initial weights of 3.52±0.01 g were fed by hand at 3% of live weight for 90 days. At the end of the study, feeding with oregano EO supplementation did not significantly affect the growth performance of fish. Except for pepsin, there were no significant differences in the activity of digestive enzymes among the control and oregano EO groups. Besides, oregano EO at the doses of 50 or 400 mg kg−1 may have the potential to increase the surface area required for digestion by increasing intestinal villi length. Moreover, all doses of oregano EO showed antimicrobial properties by decreasing the count of lactic acid bacteria in the intestine. Supplementation with 100 and 200 mg kg−1 oregano EO in diets decreased the total coliform, Escherichia coli and lactic acid bacteria counts when compared to the control group. The results showed that oregano EO may positively affect digestion and absorption without adverse effects on the growth performance of Black Sea salmon juvenile.

Essential Oil from the Stem Bark of Casuarina equisetifolia Exerts Anti-inflammatory and Anti-nociceptive Activities in Rats

Herein the chemical constituents and the anti-pain properties of the essential oil from the stem bark of Casuarina equisetifolia L. (Casuarinaceae) grown in Nigeria were evaluated. The essential oil was obtained by hydrodistillation method in an all glass Clevenger-type apparatus, and characterized by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The hot plate method was used to determine the anti-nociceptive property whereas the anti-inflammatory activity was evaluated by carrageenan-induced and formalin experimental models. The pale-yellow essential oil was obtained in yield of 0.21% (v/w), calculated on a dry weight basis. The main constituents of the essential oil were methyl salicylate (30.4%), a-zingiberene (15.5%), (E)-anethole (9.5%), b-bisabolene (8.6%), b- sesquiphellandrene (6.9%), and ar-curcumene (6.2%). In the anti-nociceptive study, the rate of inhibition increases as the doses of essential oil increases with optimum activity at the 30th and 60th min for all tested doses. The essential oil displayed anti-nociceptive activity independently of reaction time at the highest tested dose (200 mg/kg). The essential oil of C. equisetifolia moderately reduced pain responses in early and late phases of the formalin test. The oil inhibited the paw licking in the neurogenic phase (60-63%) compared to the late phase of the formalin test. The carrageenan- induced oedema model revealed the suppression of inflammatory mediators within the 1st - 3rd h. Thus, C. equisetifolia essential oil displayed both anti-nociceptive and anti-inflammatory activities independent of the dose tested. The anti-inflammatory and anti-nociceptive activities of C. equisetifolia essential oil are herein reported for the first time.

Impacts of Lavandula angustifolia Mill. and Thymbra spicata L. essential oils on postharvest gray mold of strawberries

Antifungal activities of two essential oils (EOs), derived from the Lavandula angustifolia L. and Thymbra spicata L. plant leaves were tested in current study against two isolates (M1-5 and M3-5) of Botrytis cinerea in Potato Dextrose Agar (PDA). These studies were performed in vitro and a further in vivo test with vapor contact application of the EOs was performed with strawberry fruits to confirm the antifungal activities in postharvest storage. In vitro studies were conducted with four different application doses (0.25, 0.50, 1.00 and 2.00 mL L-1) of both EOs with poisoned food technique. The highest dose (2.00 mL L-1) of L. angustifolia had a 92.50% mycelial growth inhibition on M1-5, where the same dose of same oil had 0.00% mycelial growth inhibition on M3-5. On the other hand, the highest dose (2.00 mL L-1) of T. spicata had 16.76% and 51.18% of mycelial growth inhibition on M1-5 and M3-5, respectively. The lower doses had less or no antifungal activity, thus only the highest doses were tested in the consecutive in vivo studies. Results suggested that both of the EOs had moderate impact on the prevention of disease severity at strawberry cv. Camarosa fruits, inoculated with M1-5 and M3-5 isolates. The EOs were also noted to have a significant influence on the prevention of the weight loss and loss of soluble solids concentration. Results suggested that the vapor contact application of L. angustifolia and T. spicata essential oils have potential to be alternative to synthetic fungicides for controlling gray mold in strawberry fruits caused by B. cinerea.

Effect of natural garlic essential oil on chickens with artificially infected Eimeria tenella

Chicken coccidiosis is a kind of parasitic protozoosis caused by Eimeria parasitizing in the chicken intestinal epithelial cells. Eimeria tenella is considered as a significantly virulent and harmful parasite. At present, drug resistance remains a major problem and a large number of drug residues have been found to be produced in the treatment of the disease. Hence, novel strategies are needed to avoid the harmful effects caused by the generation of various chemical drug residues to the human body and also reduce the economic loss caused by coccidiosis to the chicken industry. In this study, natural garlic essential oil was used to control Eimeria tenella infection. The anticoccidial index (ACI) was calculated according to the clinical symptoms, body weight gain, oocyst excretion and cecal lesions. The immune organ index and serum biochemical indexes were measured to verify the possible anticoccidial effects. The results showed that: compared with the infected group, continuous feeding of different doses of natural garlic essential oil could significantly reduce the clinical symptoms, cecal lesions, the number of oocysts, but increase the weight of sick chickens, and effectively improve the intestinal functions. Moreover, compared with diclazuril control group, 0.06 mL/L garlic essential oil exhibited similar anticoccidial index. The content of immune organ index, serum biochemical index IgM, IgG and IgA in 0.06 mL/L garlic essential oil group was the highest, which indicated that garlic essential oil had a significant tendency to improve the immune function of the chickens. This study also showed that the natural garlic essential oil exhibited the same beneficial effects as that of diclazuril on chicken coccidiosis, and the anti-coccidiosis index of 0.06 mL/L garlic essential oil was favorable. Thus based on the above evidences and its relatively low cost, garlic essential oil can be potentially be used as an efficient anti parasitic drug.

The improving role of savory (Satureja hortensis) essential oil for Caspian roach (Rutilus caspicus) fry: Growth, haematological, immunological, and antioxidant parameters and resistance to salinity stress

Essential oils (EOs) due to their bioactive compounds can be considered suitable dietary supplements to achieve sustainable aquaculture. The present experiment was conducted to evaluate the effects of supplementation of Caspian roach fry (Rutilus caspicus) diet with different doses of savory essential oil (SEO) (Satureja hortensis) on growth performance, haematological parameters, serum and mucus immunological indices, serum antioxidant indices, and salinity stress resistance. Caspian roach fry (2.29 ± 0.07 g) were fed with four experimental diets including basal diet as control, and basal diet incorporated with 100, 200, or 400 mg/kg diet of SEO (SEO1, SEO2, and SEO3 respectively) for 60 days. At the end of the experiment, the lowest feed conversion ratio (FCR) as well as highest final weight (FW), weight gain (WG), and specific growth rate (SGR) were observed in fish given the SEO2 diet (P < 0.05). The SEO3 group showed the lowest FW, WG, and SGR which was significantly lower than other groups (P < 0.05). Survival rate of the SEO1 and SEO2 treated groups showed a significant increase compared to the SEO3 and control groups (P < 0.05) with the highest rates found in fish received SEO2. All groups receiving SEO showed significantly higher haemoglobin (Hb) and number of white blood cells than control group (P < 0.05). The best serum levels of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were observed in fish treated with SEO2, which showed a significantly different from the control group (P < 0.05). All SEO treated fish showed significant increase in serum total immunoglobulin (total Ig), lysozyme (LYZ), and alternative complement pathway haemolytic activity (ACH50) compared to the control group (P < 0.05) with SEO2 showing the best results. Also significant improvement of mucus total Ig, LYZ, ACH50, protease and alkaline phosphatase (ALP) activities were found in treatments receiving SEO compared to those of control group (P < 0.05). All SEO treatments showed significantly higher resistance to salinity stress than those in the control group (P < 0.05). Overall, our results revealed that SEO inclusion can improve growth performance, antioxidant enzymes activities, immune responses as well as resistance of R. caspicus and 200 mg/kg diet is recommended.

The Synergistic Effect of Three Essential Oils against Bacteria Responsible for the Development of Lithiasis Infection: An Optimization by the Mixture Design.

The present study aimed to determine the chemical composition and the synergistic effect of three plants' essential oils (EOs), Eucalyptus camaldulensis (ECEO), Mentha pulegium (MPEO), and Rosmarinus officinalis (ROEO), against three bacterial strains, Proteus mirabilis, Klebsiella pneumoniae, and Staphylococcus aureus, in order to increase the antimicrobial effectiveness by the use of a low dose of essential oils, consequently decreasing the toxicity and negative impact. For this reason, an augmented simplex-centroid mixture design was used to build polynomial models in order to highlight the synergy between the essential oils against bacterial strains. Antimicrobial effect screening was performed by the disc diffusion method and the minimal inhibitory concentrations (MIC) were also studied. The gas chromatography/mass spectrometry (GC-MS) results show the richness of these essential oils by terpenic compounds, especially 1,8-Cineole and P-Cymene for ECEO, Pulegone for MPEO, and α-Pinene and Camphene for ROEO. Moreover, a significant antibacterial effect has been demonstrated and the best values were revealed by MPEO and ECEO against P. mirabilis and K. pneumoniae, with inhibition zones (IZ) of 25 and 20 mm, respectively, and an MIC of 0.0391% (v:v) against K. pneumoniae. The optimal mixtures showed a synergistic effect of essential oils, and the lowest minimal inhibitory concentrations of the mixtures (MICm) were in the order of 29.38% of MPEO, 45.37% of ECEO, and 25.25% of ROEO against P. mirabilis and in the order of 60.61% of MPEO and 39.39% of ROEO against K. pneumoniae. These results indicate the antibacterial efficacy of the three essential oils combined and suggest their importance in the treatment of urinary tract infections caused by resistant bacterial strains.

Chemical Composition and Nematicidal Properties of Sixteen Essential Oils-A Review.

Essential oils (EOs) can be a large source of new food-safe and healthy nematicidal products, due to their strong activity on crop pathogens and pests, including phytoparasitic nematodes, as well as to their low environmental persistence. This review summarizes the results from our 10-year studies on chemical features and nematicidal properties of 16 EOs with different botanical origins and compositions, i.e., the EOs from Artemisia herba-alba Asso (Asteraceae), Cinnamomum camphora (L.) J. Presl. and Cinnamomum verum J. Presl. (Lauraceae), Citrus aurantium L., Cinnamomum. sinensis L. Osbeck and Ruta graveolens L. (Rutaceae), Eucalyptus citriodora Hook, Eucalyptus globulus Labill. and Syzygium aromaticum (L.) Marry et Perry (Myrtaceae), Mentha piperita L., Monarda didyma L., Monarda. fistulosa L., Rosmarinus officinalis L. and Thymus satureioides Cosson (Lamiaceae), Pelargonium asperum Ehrh ex Willd (Geraniaceae) and Schinus molle L. (Anacardiaceae). All these EOs were chemically characterized and tested in vitro and/or in vivo for their activity against the phytoparasitic species Meloidogyne incognita Kofoid et White (Chitw.), Pratylenchus vulnus Allen et Jensen and Xiphinema index Thorne et Allen. Toxicity bioassays were conducted by exposing 2nd stage juveniles (J2) of M. incognita, mixed-age specimens of P. vulnus and adult females of X. index to 2–100 μg mL−1 concentrations of EOs or EO’s major constituents for 4–96 h and checking mortality effect after a further 24–72 h permanence in water. Egg hatchability bioassays consisted in exposing (24–48 h) M. incognita egg masses to 500–1000 mg mL−1 EO solutions followed by a 5-week hatching test in water. The in vivo experiments were undertaken in sandy soil strongly infested by M. incognita and treated with different doses of EOs, applied either in water solution or by fumigation. The effects of the treatments on nematode infestation on tomato and in soil were checked at the end of each experiment. Structure-activity relationships, as suggested by the different chemical compositions of tested EOs, were also highlighted. In agreement with literature data, our studies indicated that most of the tested EOs are highly suitable for the formulation of new safe nematicides, though still retarded by the lack of efficient stabilization processes and standardized EOs’ components and extraction techniques.

Chemical Composition of Essential Oils of Peppermint and Spearmint Dry Leaves and Their Allelopathic Effects on Wheat Species

This study was carried out to determine the chemical composition of essential oils of the spearmint and the peppermint dry leaves and their allelopathic effects on seed germination and seedling growth of different wheat species. The ratios of essential oil isolated by hydrodistillation were found to be 2.5 % and 2.0 % (w/w), respectively. The GC/MS analysis revealed that the peppermint essential oil contained 20 compounds, while spearmint essential oil incorporated 17 compounds. The main components in the spearmint essential oil were identified to be carvone (62.9 %) and limonene (8.2 %), while those of the peppermint essential oil was to be menthone (34.5 %) and menthol (41.4 %). The seed germination started to be negatively affected by 0.2 μL of essential oil and the negative effect increased in parallel with the increase in essential oil dose. The reducing effect of the mint essential oils on seed germination was the lowest for Triticum spelta and the highest for T. aestivum. In the pot trial, the negative effect began to appear with 0.8 μL of essential oil and increased with the higher doses. The effect of mint essential oils on root lengths and dry weights of single seedlings was the lowest for T. spelta and the highest for T. dicoccum. The estimated field application dose of the peppermint essential oil for the investigated wheat species was determined to be approximately 208 mL da−1.

The effect of a seed coating with Origanum vulgare essential oil on Clavibacter michiganensis subsp. michiganensis

The study aimed to evaluate the efficacy of a seed film coating with Origanum vulgare Linnaeus essential oil (EO) against Clavibacter michiganensis subsp. michiganensis (Cmm) on tomatoes. Tomato seeds (cv. Rio Grande) coated with different doses of EO derived from O. vulgare were inoculated with Cmm (1.8 × 10&lt;sup&gt;8&lt;/sup&gt; CFU/mL). O. vulgare's EO showed a remarkable inhibition effect on the Cmm growth. The EO effect against Cmm was determined based on the parameters, such as the inhibition zone and bacterial population in a seed. The GC-MS analysis of EO showed that carvacrol is the major component (at 74.05%), which may inhibit the bacterial growth. Later, we have expanded our studies to determine the inhibitory effect of the EO's mode of action on the pathogenic bacteria with a molecular docking analysis based on the molecular protein-ligand interaction. The results showed that carvacrol has a strong interaction with the bacterial expansin protein (PDB 4JJO) of Cmm and the qPCR analyses confirmed the effect of the O. vulgare treatment against Cmm. This original approach has the prominent potential to prevent seed transmission of Cmm for seed quality in the world, suggesting a method for paving the way for Cmm disease management.

Effect of a mix essential oil of Pinus merkusii (Jungh. and de Vriese) and Melaleuca leucadendra (L.) on ruminal nutrient digestibility

This research was aimed to observe the effect of mix essential oil at different doses on nutrient digestibility in the in vitro rumen fermentation. Mix essential oil consisted of pine (Pinus merkusii (Jungh. and de Vriese)) and eucalyptus (Melaleuca leucadendra (L)) essential oil in ratio of 1:1. The doses of mix essential oils added were 0, 100 and 200 μL/L of fermentation media. Feed material included elephant grass, rice bran and pollard in ratio of 60:20:20 dry matter were used as fermentation substrate. Fermentation was conducted at 39°C for 24h. Data collected included dry matter (DMD), organic matter (OMD), crude protein (CPD) and crude fibre digestibility (CFD). Results showed that the addition of mix essential oil at the level of 100 μL/L increased DMD (P<0.05), without an effect on OMD, CPD, and CFD. Furthermore, the addition of mix essential oil at the level of 200 μL/L reduced OMD and CPD (P<0.05) and did not affect DMD and CFD. In conclusion, combination of pine (Pinus merkusii (Jungh. and de Vriese)) and eucalyptus (Melaleuca leucadendra (L)) essential oil in ratio of 1:1 improve the effect of both essential oils particularly at doses 100 μL/L hence this mix essential oil potential to be used as feed additive.

Chemical Composition and Herbicidal Activities of Essential Oil from Aerial Parts of Origanum Hybrids Grown in Different Global Climate Scenarios on Seed Germination of Amaranthus palmeri

The present study aimed to investigate the changes in the essential oil contents of some Origanum hybrids grown at different carbon dioxide (400 and 800 ppm) levels in a fully automated carbon dioxide greenhouse. The chemical composition of essential oils was analyzed gas chromatography/ mass spectrometry (GC/MS). It was found that, among the Origanum hybrids, there were differences between the essential oil contents of those grown under natural conditions and controlled greenhouse conditions. While an increase in carbon dioxide level significantly increased the thymol and carvacrol components, which are among important monoterpene components, of Origanum syriacum x O. onites and O. syriacum x O. vulgare hybrids, whereas it led to a decrease in O. syriacum x O. majorona hybrid. To determine the effects on germination of Amaranthus palmeri S. Watson seeds under laboratory conditions, the essential oils were used at 0.5, 1, 2, and 4 μl/petri doses. The most effective doses of essential oils for preventing the germination of A. palmeri seed were found to be 2 and 4 μl/petri. In preventing the germination of seeds, the most effective (100 %) application for all the essential oils was achieved with O. syriacum x O. onites hybrid grown at 800 ppm. These results show that the CO2 increases that may occur as a result of climate change in the next years may lead to changes in the content of essential oils in Origanum hybrids and may have the potential to be used as bio-herbicidal to prevent the germination of A palmeri.

The combined effect of essential oils and emerging technologies on food safety and quality

Essential oils (EOs) are natural food preservatives, but they may impair the sensory characteristics of foods. Emerging technologies (ETs) can inactivate microorganisms, but high intensities of the process may compromise quality parameters. This manuscript discusses the use of EOs and ETs and presents the mechanisms of microbial inactivation in combined processes. Also, the advantages, disadvantages, and limitations of EO and ETs were explained. It was found that lemongrass, lavender, thyme, sweet basil, lime, oregano, mentha, cinnamon, citral, carvacrol, carvone, geraniol, eugenol, citrus extract, mandarin, rosemary, and clove EOs have been combined with cold plasma, ultrasound, irradiation, ultraviolet light, high hydrostatic processing, pulsed light, pulsed electric fields, ohmic heating, and ozone to inactivate pathogens, spoilage bacteria, and molds. The food matrices explored for EO and ET include meat, fish, eggs, milk, plant-based products, as well as food-container surfaces. Synergistic effects between EOs and ETs have been reported in many cases. Microbial inactivation is influenced by the type of microorganism, the intensity of ET processing parameters, type and concentration of EOs, and the composition of foods. The combined use of EOs and ETs is a strategy capable of reducing the EO doses and the ET intensity while improving food safety and quality.

Acaricidal activity of Mentha suaveolens subsp. timija, Chenopodium ambrosioides, and Laurus nobilis essential oils, and their synergistic combinations against the ectoparasitic bee mite, Varroa destructor (Acari: Varroidae)

The main objective of the present study was to evaluate under laboratory conditions the toxicity of essential oils (EOs) extracted from Mentha suaveolens L. subsp. timija (Briq.) Harley, Chenopodium ambrosioides L. and Laurus nobilis L. against Varroa destructor adult mites. Also, various combinations were prepared by mixing equal concentrations of any two and all three studied EOs and used to evaluate the combinational acaricidal effects of mixtures against adult Varroa mites. The GC/MS analysis indicated that the main chemical compounds of M. suaveolens subsp. timija EO were menthone (40.42%) and pulegone (19.22%), whereas C. ambrosioides EO is rich in α-terpinene (34.08%), isoascaridol (13.6%), p-cymene (10.95%), thymol (10.26%), ascaridole (10.25%) and carvacrol (7.75%). L. nobilis EO is mainly composed with 1,8-cineol (37.5%) and linalool (14.09%). The fumigation bioassays showed that the three tested EOs showed varroacidal toxicity, whereas no mortality has been observed on honey bees that were exposed to their higher concentrations. The highest acaricidal potency was observed with M. suaveolens subsp. timija (LD50 = 3.360 µl/Lair and LD90 = 7.300 µl/Lair). According to the combination index (CI) calculated by CompuSyn software, the ternary blend combination exhibited high synergistic effectiveness with a CI value of 0.343. All combinations have shown favorable dose reduction with DRI indexes greater than one. Our findings suggest that EO combinations tested could present a promising solution to reduce the effective doses of EOs and constitute a promising alternative to synthetic acaricides.

Effect of Essential Oils and Hydrosols from Some Selected Lamiaceae Species on Redroot Pigweed (Amaranthus retroflexus L.)

Allelopathy refers to chemical effect of a plant direct or indirect on germination, growth or development of neighboring plants. Allelopathy can be considered as a component of biological control that reduces the development of other plants. This study was carried out to determine the effect of Greek sage (Salvia fruticosa Miller), basil (Ocimum basilicum L.), Dragonhead (Dracocephalum moldavica L.), spearmint (Menta spicata L.), sage (Salvia officinalis L.), lemon balm (Melissa officinalis L.), oregano (Origanum onites L.) and thyme (Thymus kotschyanus Boiss.) on the germination of redroot pigweed (Amaranthus retroflexus L.) which causes significant yield loss in agricultural production. Essential oil (9, 18, 36 µL/petri) and hydrosols (50, 75, 100%) of aromatic plants were applied to determine their inhibition effects on seed germination of A. retroflexus. The experimental design for in vitro was a randomized design with five replications. It has been shown that germination rate was decreasing by the increased concentration of essential oil and hydrosols of the tested plant species. Also, total germination inhibition of A. retroflexus depended on the essential oil doses; the rate ranged from-2.9 to 85%. Amongst the essential oils, the highest effect was observed in spearmint with 7% germination rate. It could be considered as an important solution, which would contribute in Integrated Weed Management of A. retroflexus by using different concentrations of essential oil and hydrosols from aromatic plants.

Assessment of Cytotoxic and Apoptotic Effects of Salvia syriaca L. in Colorectal Adenocarcinoma Cell Line (Caco-2).

This work is aimed to elucidate cytotoxic and apoptotic effects of Salvia syriaca essential oil and its chemical composition by GC-MS. The human colon cancer cells (Caco-2) were treated with different essential oil concentrations for 24 h. Crystal violet test was used to determine cell viability at 630 nm by using an ELISA reader. Apoptotic processes were measured by Annexin V-FITC Apoptosis Assay Kit. Germacrene D (21.77%), trans-β-ocimene (14.66%), β-pinene (9.07%), α-cadinol (8.19%) and α-pinene (6.50%) were the main components of oil determined by GC-MS. Moreover, we observed that the cytotoxic effect was increased with an increasing dose of essential oil. The EC50 value was calculated as 63.5 µg/mL. An increase in the percentage of apoptotic cells was observed after treatment of Caco-2 cells with S. syriaca essential oil revealed by image-based cytometry. A nearly 6-fold increase was found in annexin-positive cells after treatment. In terms of mRNA levels, RT-PCR analysis indicated that, although Bax and Caspase-3 were increased, Bcl-2 was decreased after oil treatment. According to our results, S. syriaca essential oil has promising phytochemicals that might be useful in cancer treatment due to their relatively cytotoxic and apoptotic activities in Caco-2 cells.

Effect of Cyclotrichium niveum Essential Oil on Rumen Microbial Fermentation and in vitro Digestibility of Barley

The digestibility of feed in ruminants and the volatile fatty acids (VFA) resulting from digestion directly affect animal performance. It has long been studied on the use of essential oils as an alternative to antibiotics to ensure optimum conditions for the rumen environment. Cyclotrichium niveum (mountain mint) essential oil is rich in antimicrobial agents. In this study different doses (0, 50, 100 and 150 mg/L of culture fluid) of Cyclotrichium niveum essential oil was incubated 24 hours with barley in diluted ruminal fluid takes from fistulated cows fed with a 40:60 concentrate:forage diet in order to assess the effects on rumen microbial fermentation and in vitro true digestibility of barley. True digestibility of barley was determined in ANKOM Daisy Incubator. All doses of Cyclotrichium niveum significantly (P&amp;lt;0.001) decreased the in vitro dry matter (DM), organic matter (OM), neutral detergent fiber (NDF) digestibility of barley. Cyclotrichium niveum essential oil negatively affected end-products of rumen fermentation; the value of the measured rumen volatile fatty acids (VFA: acetate, propionate, butyrate, isobutyric acid, valerate and isovalerate) significantly decreased compared to the control group (P&amp;lt;0.001). Carbon dioxide and methane gases created as a result of incubation in rumen fluid were calculated using volatile fatty acid values formed in rumen fluid. The addition of Cyclotrichium niveum essential oil significantly reduces the CO2 in rumen fluid (P&amp;lt;0.001). Methane (CH4) gas from rumen fluid was significantly decreased in treatment groups compared the control group (P &amp;lt;0.001) While end-products of rumen fermentation parameters significantly decreased with all doses of Cyclotrichium niveum essential oil, rumen pH has increased (P&amp;lt;0.05). The results show that when the Cyclotrichium niveum essential oil incubated with barley significantly inhibited the rumen microbial activity and overall fermentation process of rumen.

Essential oils as growth-promoting additives on performance, nutrient digestibility, cecal microbes, and serum metabolites of broiler chickens: a meta-analysis.

ObjectiveThe purpose of this meta-analysis was to evaluate the effect of dietary essential oils (EOs) on productive performance, nutrient digestibility, and serum metabolite profiles of broiler chickens and to compare their effectiveness as growth-promoting additives against antibiotics.MethodsPeer-reviewed articles were retrieved from Web of Science, Science Direct, PubMed, and Google scholar and selected based on pre-determined criteria. A total of 41 articles containing 55 experiments with 163 treatment units were eligible for analyses. Data were subjected to a meta-analysis based on mixed model methodology considering the doses of EOs as fixed effects and the different studies as random effects.ResultsResults showed a linear increase (p<0.001) on body weight gain (BWG) where Antibiotics (FCR) and average daily feed intake decreased (p<0.001) linearly with an increasing dose of EOs. Positive effects were observed on the increased (p<0.01) digestibility of dry matter, crude protein, ether extract, and cecal Lactobacillus while Escherichia coli (E. coli) population in the cecum decreased (p<0.001) linearly. There was a quadratic effect on the weight of gizzard (p<0.01), spleen (p<0.05), bursa of fabricius (p<0.001), and liver (p< 0.10) while carcass, abdominal fat, and pancreas increased (p<0.01) linearly. The dose of EOs linearly increased high density lipoprotein, glucose, protein, and globulin concentrations (p<0.01). In comparison to control and antibiotics, all type of EOs significantly reduced (p<0.001) FCR and tended to increase (p<0.1) BWG and final body weight. Cinnamaldehyde-compound was the only EOs type showing a tendency to increase (p<0.1) carcass weight, albumin, and protein of serum metabolites while this EOs together with EOs-Blend 1 decreased (p<0.01) E. coli population. Low density lipoprotein concentration decreased (p<0.05) with antibiotics and carvacrol-based compound when compared to the control group.ConclusionThis evidence confirms that EOs are suitable to be used as growth promoters and their economical benefit appears to be promising.

Repellent Effect of the Caraway Carum carvi L. on the Rice Weevil Sitophilus oryzae L. (Coleoptera, Dryophthoridae).

Simple SummarySitophilus oryzae is one of the main insects that attack stored products around the world. Effective and environmentally friendly substances for managing storage pests are still being sought. Natural plant substances are tested as an alternative to chemical methods. Therefore, laboratory tests were carried out to check the effect of various concentrations of caraway essential oil and L-carvone on rice weevil. The abundance, emigration and mortality of this species were recorded. The highest repellent effect and the highest mortality of Sitophilus oryzae were caused by 0.1% L-carvone and 0.5% caraway essential oil. Lower concentrations of the tested compounds showed stronger repellant properties than higher concentrations.The aim of the study was to check the effect of Carum carvi L. essential oil and L-carvone on the emigration, repellence and mortality of Sitophilus oryzae L. In the experiments with caraway essential oil, concentrations of 0.1%, 0.5% and 1% were used, and concentrations of 0.05, 0.1, 0.5 and 1% were used with L-carvone. We assessed whether, in what concentrations and after what exposure time the substances acted on S. oryzae as repellents and/or insecticides. The laboratory tests were carried out at 29 ± 1 °C with 60 ± 5% relative humidity (RH). The deterrence, mortality and abundance of insects were noted after 1, 2, 3, 4, 5, 24 and 48 h. For caraway essential oil and L-carvone, the highest repellency was not shown in the highest concentrations that were used in the tests but in the lower concentrations of 0.5% and 0.1%, respectively. In all used concentrations, caraway essential oil showed repellent effects on S. oryzae. The highest repellency (60–98%) was caused by 0.5% caraway essential oil after 1, 2, 3, 4 and 5 h of research and by 0.1% L-carvone (16–100%). The highest mortality of S. oryzae was caused by 0.5% caraway essential oil and 1% L-carvone. L-carvone at a concentration of 0.05% did not cause mortality in S. oryzae. In conclusion, the greatest repellent effects on S. oryzae were caused by lower doses of caraway essential oil and L-carvone. These compounds do not show the normal relationship described in the previous literature on warehouse pests, in which the repellency increased with increasing concentrations of the tested plant material.