Application Of Plant Essential Oils Research Articles

Sodium alginate/gelatin hydrogel spheres loaded with Fructus Ligustri Lucidi essential oil: Preparation, characterization and biological activity

The application of plant essential oils in the food industry is often hindered by their poor water solubility and high volatilize. Encapsulation has emerged as an effective solution to this problem. This study focuses on the preparation of Fructus Ligustri Lucidi essential oil gel spheres (FEOH) based sodium alginate and gelatin. The optimum formulation for FEOH was established by Box-Behnken Design response surface testing, resulting in a composition of 10 % FEO, 5 % TW20 and 2 % CaCl2. This formulation achieved an encapsulation efficiency of 85.56 %. FTIR and SEM results indicated the successful encapsulation of FEO within the gel spheres. Furthermore, DSC and TGA results showed that encapsulation enhanced the thermal stability of the essential oil. At room temperature, the water content of FEOH exceeded 90 %, and it showed the highest swelling ratio of 62.5 % in an alkaline medium at different pH conditions. The in vitro release behavior showed that FEOH was released up to 85.28 % in oil-based food simulants within 2 h. FEOH showed strong antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 128 mg/mL against Staphylococcus aureus and 256 mg/mL against Escherichia coli. The gel spheres obtained in this research show significant potential as food preservatives in food matrices.

Edible chitosan-based Pickering emulsion coatings: Preparation, characteristics, and application in strawberry preservation

The long-term application of plant essential oils in food preservation coatings is limited by their poor water solubility and high volatility, despite their recognized synergistic antimicrobial effects in postharvest fruit preservation. To overcome these limitations, a Pickering emulsion loaded with thyme essential oil (TEO) was developed by utilizing hydrogen bonding and electrostatic interactions to induce cross-linking of chitosan particles. This novel emulsion was subsequently applied in the postharvest storage of strawberries. The shear-thinning behavior (flow index <1) and elastic gel-like characteristics of the emulsion made it highly suitable for spray application. Regarding TEO release, the headspace concentration of TEO increased from 0.21 g/L for pure TEO to 1.86 g/L after two instances of gas release due to the stabilizing effect of the chitosan particles at the oil-water interface. Notably, no phase separation was observed during the 10-day storage of the emulsion. Consequently, the emulsion was successfully employed for the postharvest storage of strawberries, effectively preventing undesirable phenomena such as weight loss, a decrease in firmness, an increase in pH, and microbial growth. In conclusion, the developed Pickering emulsion coating exhibits significant potential for fruit preservation applications, particularly for extending the shelf life of strawberries.

The performance of plant essential oils against lactic acid bacteria and adverse microorganisms in silage production.

Plant essential oils have played an important role in the field of antibiotic alternatives because of their efficient bacteriostatic and fungistatic activity. As plant essential oils are widely used, their activity to improve the quality of plant silage has also been explored. This review expounds on the active ingredients of essential oils, their bacteriostatic and fungistatic activity, and mechanisms, as well as discusses the application of plant essential oils in plant silage fermentation, to provide a reference for the development and application of plant essential oils as silage additives in plant silage fermentation feed.

Antifungal and mycotoxin detoxification ability of essential oils: A review

With increased popular awareness of food safety and environmental protection, plant essential oil has attracted interest due to the absence of residue, its high efficiency, antioxidant, immune regulation, antibacterial, insecticidal, and other advantages. Their application in degradation and elimination of mycotoxin toxicity has attracted increasing attention. This paper reviews the structure, antibacterial activity, antibacterial mechanism, and toxic effects of essential oils. The inhibitory effects of various essential oils on different mycotoxins were studied. The research progress on the inhibitory effects of plant essential oils on fungi and mycotoxins in recent years was summarized to provide reference for the application of plant essential oils.

Cytotoxic Evaluation of the Essential Oils from Korean Native Plant on Human Skin and Lung Cells

Plant essential oils are used in products such as fragrances and cosmetics due to their individual aromatic characteristics. Currently, essential oils are not only used in cosmetics but also in pharmaceutical products with anti-bacterial, anti-viral, anti-fungal, anti-parasitic, insecticidal, anti-cancer, neuroprotective, psychophysiological, or anti-aging effects. Despite their pharmaceutical properties, some studies reported cytotoxic effects in high doses. Therefore, for pharmaceutical purposes, the margin of safety of essential oils needs to be examined. Herein, we evaluated the IC50 of 10 essential oil from Korean native plants: Juniperus chinensis L. var. sargentii Henry, Citrus natsudaidai Hayata, Citrus reticulata Blanco, Citrus unshiu (Yu. Tanaka ex Swingle) Marcow, Artemisia capillaris Thunb, Aster glehnii F. Schmidt, Juniperus chinensis L, Zanthoxylum schinifolium Siebold &amp; Zucc, Zanthoxylum piperitum (L.) D, and Cinnamomum loureirii. In addition, gene regulation of the cell-cycle gene and apoptosis marker CASP3 was examined at the IC50 level. The purpose of this study was to describe the toxic concentrations of essential oils extracted from Korean native plants, thereby providing toxic concentration guidelines for inclusion in a toxicity database and in the application of plant essential oils in various fields.

Application of plant essential oils in controlling wood mold and stain fungi

The antifungal activities of 19 plant essential oils against six wood mold and stain fungi (Aspergillus niger, Penicillium citrinum, Trichoderma viride, Botryodiplodia theobromae, Fusarium moniliforme, and Alternaria alternata) were investigated with the in vitro medium method. The chemical compositions and volatilization rates of the essential oils were analyzed by gas chromatography–mass spectrometry and oven heating, respectively. Antifungal effects of the essential oils on fresh Pinus massoniana wood were evaluated by dipping treatment. The average antifungal efficacies of the essential oils varied from 0.1 to 1.0, and oils of Cinnamomum cassia, Syzygium aromaticum, and Thymus mongolicus showed the greatest antifungal activities and completely inhibited the growth of all six fungi. The essential oils presented great differences in their main chemical components, and a significant negative linear correlation (Pearson correlation coefficient = -0.627, p &lt; 0.01) was found between antifungal efficacy and volatilization rate, indicating that both chemical composition and volatilization rate are important factors influencing the antifungal activities of essential oils. Eight essential oils effectively inhibited the growth of fungi in Pinus massoniana wood with an absorption of 65.51 g/m2 ± 13.78 g/m2, and they have the potential to be environmentally friendly anti-mildew agents.

Antifungal activity of the lemongrass and clove oil encapsulated in mesoporous silica nanoparticles against wheat's take-all disease

Combined application of plant essential oils (EOs) with known antimicrobial effects and silica nanocapsules with high loading capacity and protection capability of the EOs make them proper candidates for creating environmentally friendly fungicides. In this study, EOs of the Lemongrass (LGO) and Clove (CO) were used against Gaeumannomyces graminis var. tritici (Ggt), a causal agent of take-all disease of wheat. To provide controlled delivery of the EOs, they were encapsulated into mesoporous silica nanoparticles (MSNPs) and then compared to the effects of pure EOs both in- vitro and in- vivo. MSNPs were synthesized via the sol-gel process. Various techniques such as Fourier transform infrared spectroscopy (FTIR), the Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), and UV–Vis spectroscopy were used to evaluate the successful loading of the EOs into the pore of MSNPs. The encapsulation efficiency (EE) was calculated as high as 84.24% for LGO and 80.69% for CO, while loading efficiency (LE) was determined 36% and 29% for LGO and CO, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) displayed spherical shapes and porous structures with average diameters of 50–70 nm. Recognition of the main components of the EOs via gas chromatographic-mass spectrometry (GC–MS) before and after the EO loading, detected eugenol and citral as the most frequent compounds in LGO and CO, respectively. For antifungal test in- vitro, selected concentrations of the pure EOs, EOs loaded in MSNPs (EOs- MSNPs) and Mancozeb ® fungicide based on pre-tests were mixed using potato dextrose agar (PDA). The inhibition percentage (IP) of fungal growth at each concentration, as well as minimum inhibition concentration (MIC) and minimum fungicidal concentrations (MFC) were obtained. The results indicated that antifungal effects in the encapsulated form increased by up to three times. In- vivo, the sterile wheat seeds were treated with pure EOs, EOs-MSNPs, and mancozeb at MFC concentration. Also, in order to keep on the EOs-MSNPs around the seeds, sodium alginate was used. The consequences of in- vivo experiments indicated that rate of disease control in presence of EOs-MSNPs and mancozeb was the same (~70%) and higher than pure EOs (LGO: 57.44%, CO: 49%). Also, improving the growth parameters in wheat plant, the covering of the EOs-MSNPs in alginate, had better control (84%) than that of EOs-MSNPs alone. Further, the release kinetics studies showed a gradual release of LGO and CO from MSNPs for four weeks in water and for five weeks in the soil-plant system. To the best of our knowledge, this is the first report of the control effect of LGO, CO, and their nanocapsule in MSNPs against the take-all disease of wheat. These results showed that the EOs-MSNPs can be a safe product for the efficient control of take-all disease in wheat crop.

Data on cytotoxicity of plant essential oils in A549 and Detroit 551 cells.

To secure the safety for industrial applications of plant essential oils, it is necessary to determine the inhibitory concentration and inhibitory mechanism of cell proliferation in skin cells and lung cells. Considering inhalation through the respiratory system and skin contact of humans with essential oils, we used human lung cancer cells A549 and human skin fibroblasts Detroit 551 cells for all experiments. In this study, we examined IC50 values and protein levels of cell cycle markers (cyclin A, cyclin B, cyclin D, and cyclin E) and apoptosis marker (caspase-3) after exposure to 10 plant essential oils, including Dendranthema indicum (L.) Des Moul, Peucedanum japonicum Thunb, Dendranthema zawadskii var. latilobum (Maxim.) Kitam, Agastache rugosa (Fisch.&Mey.) Kuntze, Vitex rotundifolia L.f, Pinus rigida Mill; Orixa japonica Thunb, Pinus strobus L, Chamaecyparis pisifera (Siebold et Zucc.) Endl. var. filifera Beissn. et Hochst, and Citrus sunki Hort. ex Tanaka. After the treatment of A549 and Detroit 551 cells to varying concentrations of the 10 plant essential oils, IC50 values were determined by CCK analysis, whereas protein expressions of the four cyclins and caspase-3 were identified by Western blotting analysis. We believe that by examining the degree and mechanism of cell proliferation inhibition exerted by essential oils on skin and lung cells of humans, data obtained in this study can provide guidelines for the industrial application of plant essential oils.

The potential application of plant essential oils to control Pediculus humanus capitis (Anoplura: Pediculidae).

The human head louse, Pediculus humanus capitis (Anoplura: Pediculidae), is an ectoparasite confined to the scalp and human hairs. The repeated use of insecticides for the control of head lice during past decades has resulted in the development of marked levels of resistance. Natural compounds such as essential oils (EOs) have been suggested as alternative sources for insect control agents. In order to introduce a new pediculicide based on EOs, the effectiveness of the product and their effects on human being must be analyzed. In consequence, the biological activity of EOs from the leaves and fruits of Schinus areira (Anacardiaceae) and the leaves of Thymus vulgaris (Lamiaceae), Aloysia polystachya and Aloysia citriodora (Verbenacea) were evaluated against the eggs and adults of P. humanus capitis by fumigant and contact toxicity bioassays. Additionally, dermal corrosion/irritation tests were performed on New Zealand albino rabbits. In a fumigant bioassay, EOs from the leaves and fruits of S. areira were the most toxic against P. humanus capitis adults while these EOs and T. vulgaris were the most effective against the eggs. In contact bioassay, the EO from T. vulgaris was the most toxic against both stages. In the corrosion/irritation tests, the EOs did not produce dermal effects. According to the results, the essential oils from the leaves of T. vulgaris would be a valid tool for the management of P. humanus capitis. This EO produces a high knockdown effect in adults (followed by mortality) and toxicity in the eggs when it is applied for 21 min at a low concentration.

Application of plant essential oils in prevention of fungal growth on Para rubber wood

Antifungal activities of essential oils (cinnamon, clove, eucalyptus, peppermint and lemongrass oils) against moulds (Penicillium sp., Aspergillus niger and Aspergillus versicolor) isolated from rubber wood surfaces were examined. Clove oil possessed consistent antifungal activity with the minimal inhibitory concentration (MIC) of 5 μl ml−1 against all these fungi, while cinnamon oil had MICs from 2.5 to 10 μl ml−1. However, only dip treatment with cinnamon oil inhibited the growth of A. niger on rubber wood for at least 25 weeks.

Natural Plant Essential Oils Do Not Inactivate Non-enveloped Enteric Viruses

The application of plant essential oils (EOs) (hyssop and marjoram) was evaluated for inactivation of non-enveloped viruses using murine norovirus and human adenovirus as models. No significant reduction of virus titres (TCID(50)) was observed when EOs were used at different temperatures and times.

EVALUATION OF PLANT ESSENTIAL OILS FOR CONTROL OF POSTHARVEST BROWN AND GRAY MOLD ROTS ON APRICOT

ABSTRACTIn this study, antifungal activities of Thymus vulgaris L., Eugenia caryophyllata L., Cinnamomum zeylanicum Blume and Carum copticum L. essential oils against Monilinia fructicola and Botrytis cinerea, two important postharvest pathogens of stone fruit, were investigated under in vivo studies. Results showed that the essential oil treatments, especially T. vulgaris and E. caryophyllata oils, had a good antifungal activity in reduction of both disease incidence and disease severity of brown and gray mold rots caused by M. fructicola and B. cinerea on apricots, respectively. Gas chromatography (GC) and GC/mass spectrometry analysis of tested essential oils showed that thymol (37.55%), eugenol (48.76%), cinnamaldehyde (90.33%) and thymol (50.88%) were the main components of T. vulgaris, E. caryophyllata, C. zeylanicum, C. copticum oils, respectively. Application of C. copticum and E. caryophyllata oils on apricot fruit showed a significant effect on fruit quality retention as evaluated with weight loss (%), fruit firmness, total soluble solids, titratable acidity and maturity index in sensory parameters. These results revealed that T. vulgaris and E. caryophyllata oils could be natural alternatives to fungicides in the control of M. fructicola and B. cinerea infections.PRACTICAL APPLICATIONSBecause of problems related to synthetic fungicide application, calls for research into new potential safe strategies for control of postharvest decay in crops. Plant products, especially essential oils, are one of the most promising groups of natural compounds for development of indigenous nature, nonmammalian toxicity and antimicrobial agents and their employment for the control of different postharvest pathogens is also well documented. The results of in vivo (cold storage of fruits) experiments, in this study, showed that essential oil treatment had significant effects on fungal growth. The number of infected fruits and disease severity were reduced in oil‐treated fruit and with increase of essential oil concentration the fungal growth decreased. Therefore, these compounds could be an alternative to chemical fungicides for the control of postharvest fungal diseases on apricot fruits. In addition, the application of plant essential oils could be named as new safe method for control of agricultural products.

Potential application of plant essential oils at sub-lethal concentrations under extrinsic conditions that enhance their antimicrobial effectiveness against pathogenic bacteria

The aim of the present study was to assess the effect of extrinsic factors on the antimicrobial effectiveness of essential oils (EOs) against medically important gram positive and gram negative bacteria. Clove, oregano, bay and cinnamon essential oils were tested against Salmonella typhimurium, Escherichia coli, Bacillus cereusand Listeria innocua. Agar diffusion test was used to estimate the strength of the essential oil. Clove was most effective against all groups of bacteria. The minimum inhibition concentrations (MIC) of the four essential oils ranged from 1.25 to 3.50% (v/v) as determined by turbidimetric technique using Biocreen C, analyzer. In order to test the combined effect of pH, sodium chloride, temperature and EOs on the growth of bacteria, the concentrations of the EOs were set at 0.03125% (v/v) below MICs. A synergistic effect against the test bacteria was achieved at the concentration 1.2% (w/v) NaCl and either oregano or clove oil (P < 0.01), however clove was bactericidal on both classes of bacteria at 37°C, pH 5.5 and in combination with NaCl at 1.8% (w/v) pH (7.3), suggesting that EOs can be combined with NaCl at low concentrations overcome organoleptic effects in food and inhibit growth of pathogenic bacteria. Key words: Antimicrobial, bacteria, essential oils, extrinsic factors.

The Potential Application of Plant Essential Oils as Natural Preservatives Against Escherichia coli O157:H7

Investigation were carried out to compare the efficiency of three plant essential oils; Zataria multiflora, Carum carvi and Mentha piperita as natural food preservatives. The effect of these plant essential oils at concentrations of 0.0, 0.3, 0.6 and 1% was studied against inoculated Escherichia coli O157:H7 (10(5) cfu mL(-1)) in prepared commercial chicken soup stored at 8 and 35 degrees C over seven (168 h) and three (72 h) days, respectively by plate count technique on CT-SMAC agar. Zataria multiflora was the most effective essential oil against the bacterium in all concentrations, followed by Mentha piperita and Carum carvi. The maximum inhibitory effects of all essential oils were seen at 1% concentration. The inhibitory effects were affected by the incubation temperature as well as by the type and concentrations of essential oils. The 1% concentration of Mentha piperita and 0.6 and 1% concentrations of Zataria multiflora essential oil showed bacteriostatic effect on growth of Escherichia coli O157:H7 at 35 degrees C. Also 1% concentration of Carum carvi, 0.6 and 1% concentrations of Mentha piperita and 0.6% concentration of Zataria multiflora essential oil had bacteriostatic effect while 1% concentration of Zataria multiflora essential oil showed bactericidal effect on the bacteria during the incubation period at 8 degrees C. It is concluded that selected plant essential oils have promising inhibitory effects on Escherichia coli O157:H7 in chicken soup and could be considered as natural food preservatives. This is especially relevant at a time when there is an increasing interest in finding more natural alternatives to many existing preservatives.

Ultrastructural studies on antimicrobial efficacy of thyme essential oils on Listeria monocytogenes

Listeria monocytogenes has gained increasing attention as a pathogen of public health importance owing to large numbers of food-borne outbreaks of listeriosis. Because of negative consumer perception of chemical preservatives, attention is shifting towards natural alternatives. Particular interest has been focused on the potential application of plant essential oils. The objective of the present study was to determine ultrastructural changes brought about by essential oils from two types of thyme, Thymus eriocalyx and Thymus x-porlock, on Listeria monocytogenes. Minimal inhibitory (MIC) and minimal bactericidal (MBC) concentrations and bactericidal kinetics of the oils were determined. Listeria monocytogenes were treated with essential oils from two thyme species and observed under a transmission electron microscope. The oils from the above plants were found to be strongly antimicrobial. Analysis of the oils by gas chromatography and gas chromatography/mass spectrometry lead to the identification of 18 and 19 components in T. eriocalyx and T. x-porlock oils, respectively. Listeria monocytogenes treated with essential oils from the two thyme species exhibited a thickened or disrupted cell wall with increased roughness and lack of cytoplasm. The antilisterial effects of thyme oil are stronger than the action of electric shocks in combination with nisin reported in the literature. It is concluded that essential oils such as thyme oil, which inhibited the growth of L. monocytogenes at low concentrations, could be considered as preservative materials for some kinds of foods; they could find an application as additives to foodstuffs in storage to protect them from listerial contamination.

The potential application of plant essential oils as natural food preservatives in soft cheese

Investigations were carried out to assess the efficiency of four plant essential oils; bay, clove, cinnamon and thyme as natural food preservatives. The effect of the plant essential oils at concentrations of 0·1, 0·5 and 1% was studied in low-fat and full-fat soft cheese against Listeria monocytogenes and Salmonella enteritidis at 4° and 10°C respectively, over a 14-day period. The composition of the cheese was shown to be an important factor in determining the effectiveness of the plant essential oils. In the low-fat cheese, all four oils at 1% reduced L. monocytogenes to ≤1·0 log10cfu ml−1. In contrast, in the full-fat cheese, oil of clove was the only oil to achieve this reduction. Oil of thyme proved ineffective against S. enteritidis in the full-fat cheese, yet was equally as effective as the other three oils in the low-fat cheese, reducing S. enteritidis to ≤1·0 log10cfu ml−1from day 4 onwards. It is concluded that selected plant essential oils can act as potent inhibitors of L. monocytogenes and S. enteritidis in a food product.