Eucalyptus Essential Oil Research Articles

Anti-aspergillosis and anti-mucormycosis potential of eucalyptus essential oil based O/W nanoemulsions containing azole based drugs from Eucalyptus globulus

Antifungal azole drugs like fluconazole, itaconazole and ketoconazole are widely used for treatment of fungal related diseases including aspergillosis and mucormycosis. This study aimed at biosynthesis of fluconazole, itaconazole and ketoconazole containing oil/water (O/W) nanoemulsions (NE) using Eucalyptus essential oil and its effect against aspergillosis and mucormycosis. Nanoemulsions were synthesized having eucalyptus essential oil, surfactants: tween 80, and co-surfactant: ethanol. Zeta potential, pH, conductivity and droplet size of nano-formulations were studied by using Zeta sizer. Nanoemulsions were analyzed by UV–VIS, FT-IR and fluorescent techniques. Stability studies were conducted by storing the nanoemulsions at different conditions for 60 days. Anti-aspergillosis, anti-mucormycosis and drug release pharmokinetics were evaluated. Average size of nanoemulsions ranged from 245 to 415 nm along with zeta potential from − 9.20 to − 25.4 mV. Encapsulation efficiency of drug loaded nanoemulsions was ranged from 40 to 50%. Nano-droplets displayed stability after 60 days of storage. Considerable anti-aspergillosis and anti-mucormycosis activities were detected. Among all formulations, F1NEs depicted high antifungal activity against Aspergillus strains MTCC 277, MTCC 343 as observed by zone of inhibition (ZOI) values. Against Mucor spp strain MTCC 3373, visual pictures clearly showed substantial inhibition in fungal growth. Pharmokinetic study shown that all nanoformulations showed Korsmeyer–Peppas model.

Development of Antibacterial Thermoplastic Starch with Natural Oils and Extracts: Structural, Mechanical and Thermal Properties.

In this study, the influence of the incorporation of eucalyptus (EO), tea tree (TT) and rosemary (RO) essential oils and Chiriyuyo extract (CE) on the structure and properties of thermoplastic starch (TPS) obtained from potato starch, glycerin and water was evaluated. All oils and the extract were used at a concentration of 0.5 g/100 g of TPS, while for TT, the effect of the concentration was also studied. The mixtures obtained were processed by extrusion and thermocompression molding. The sheets were characterized by XRD, FTIR, TGA, SEM and analyses of their mechanical properties, antimicrobial characteristics and biodegradability. The results show that the use of small concentrations of the oils in 70TPS does not induce changes in the TPS structure according to the results of XRD, FTIR and TGA, with each essential oil and CE affecting the mechanical properties unevenly, although in all cases, antimicrobial activity was obtained, and the biodegradability of TPS in soil was not modified. An increase in the concentration of TT in 60TPS causes marked changes in the crystallinity of TPS, providing a greater modulus with a higher concentration of TT. Regardless of the amount of TT, all sheets maintain antimicrobial characteristics, and their biodegradation in soil is delayed with a higher oil content.

Uticaj etarskih ulja na osobine biopolimernih filmova na bazi divljeg lana (Camelina sativa L.)

The aim of this work was the activation of biopolymer material based on wild flax cake (Camelina Sativa) with eucalyptus and rosemary essential oils added in different concentrations (0.5%, 1% and 2%). The wild flax cake, left over after the cold pressing of the oil, was used to obtain biopolymer films. To obtain active packaging, essential oils were added to this biopolymer material and the influence of the addition of essential oils on the physico-chemical, mechanical, barrier and biological properties of biopolymer films based on wild flax cake was examined. The obtained results showed the most significant influence on water vapor permeability. The control sample had a water vapor permeability value of 5.43 g/m 2 h, while in the sample with 2% added eucalyptus essential oil, this value was 3.14 g/m 2 h. Antioxidant activity was also confirmed in the control sample without added essential oils (60.10%), but with the addition of 2% eucalyptus essential oil, this value increased to 78.54%. Eucalyptus essential oil proved to be more effective than rosemary oil on the investigated properties of the films. The addition of essential oils to biopolymer films broadens the spectrum of functional properties, including the improvement of mechanical, barrier and biological properties.

Evaluation of the antimicrobial activity of Eucalyptus radiata essential oil against Escherichia coli strains isolated from meat products.

The present study sought to evaluate the antimicrobial and anti-adherent potential of Eucalyptus radiata essential oil against food-borne strains of Escherichia coli. The study was performed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). In addition, the disk diffusion technique was used to evaluate the association of Eucalyptus radiata essential oil with synthetic antimicrobials. The Minimum Inhibitory Adherence Concentration (MIC) was also performed. The results revealed that E. radiata showed antimicrobial activity against the E. coli strains tested, with MIC values ranging from 500 μg/mL to 1000 μg/mL and MBC values ranging from 500 μg/mL to 1,024 μg/mL. As for the associations, it was observed that E. radiata oil exhibited a synergistic effect for some antibiotics, especially Ceftriaxone, with greater interference from the essential oil. Furthermore, it was effective in inhibiting the adherence of bacterial strains of E. coli, showing a more significant antibiofilm effect than the antibacterial agent 0.12% chlorhexidine digluconate. In summary, the essential oil of E. radiata showed antimicrobial potential against strains of E. coli of food origin, and can therefore, through in-depth studies, be used alone or in association with synthetic antimicrobials to combat infections caused by this pathogen.

Acaricidal activity of Eucalyptus essential oil based nanoformulations against ticks in Goats

Tick infestation poses a major threat to the lifestyle of livestock. The main tick species found in domestic animals of India is Rhipicephalus [Boophilus] microplus. Several plants have the ability to inhibit the growth of the ticks in domestic animals.

Essential Oil of Eucalyptus: A Natural Solution for Treating Pediculosis

Objective: Pediculosis is a condition caused by the infestation of Pediculus Humanus Capitis. The pesticides used in current formulations exhibit toxicity and carcinogenic effects on consumers. This study aimed to investigate the pediculicidal activity of the essential oil from Eucalyptus Globulus leaves, with the intention of adding it as an active ingredient in pediculicidal formulations to replace harmful chemicals.
 Design/methodology/approach: In vivo tests were conducted to assess the repellency and mortality of the essential oil obtained through hydrodistillation. The major components were determined through gas chromatography-mass spectrometry analysis. Additionally, proximate, and chemical composition analyses were performed on the eucalyptus leaves using ASTM E871, ASTM E872, ASTM D1104, TAPPI T264, TAPPI T207, ASTM D1106, and ASTM D1104 methods.
 Results: A repellency of 66.66% and 100% mortality within 2.26 minutes were obtained in the in vivo tests. The yield of hydrodistilled essential oil was 4 mL/kg, primarily composed of 71.04% 1,8-cineole, 18.94% 4-Ethyl-m-xylene, 2.72% γ-Terpinene, and 1.23% L-α-Pinene. Furthermore, the composition of eucalyptus leaves was determined as 61.25% moisture, 30.32% volatile matter, 6% ash, 2.40% fixed carbon, 11.22% acetone extractives, 33.03% water extractives, 31.49% lignin, 69.33% holocellulose, 62.09% cellulose, and 7.24% hemicellulose.
 Limitations on study/implications: The pediculicidal activity study was conducted solely on the essential oil, and further testing on the formulation of the finished product is necessary.
 Findings/conclusions: The pediculicidal activity study was conducted solely on the essential oil, and further testing on the formulation of the finished product is necessary.

Insect repellent and insecticidal potential of two Eucalyptus species essential oils from subtropical desert climate

Insect repellent and insecticidal potential of two Eucalyptus species essential oils from subtropical desert climate

In Vitro Effect of Eucalyptus Essential Oils and Antiseptics (Chlorhexidine Gluconate and Povidone-Iodine) against Bacterial Isolates from Equine Wounds.

Considering the increasing antibiotics resistance, there has been a propensity to replace them with antiseptics when it comes to wound management and treatment. Nevertheless, in recent years, there have been reports regarding resistance to antiseptics by some bacterial strains. There is also concern about the environmental impact of these substances. The aim of this study was to compare the antimicrobial efficacy of antiseptics and eucalyptus essential oils on bacterial strains from horse's wounds. We used twelve Escherichia coli, eight Staphylococcus aureus, two Staphylococcus pseudintermedius, one Staphylococcus vitulinus and one Staphylococcus saprophyticus strains from equine wounds. The effect of Eucalyptus radiata essential oil, Eucalyptus globulus essential oil, povidone-iodine and chlorhexidine gluconate against the isolated strains was evaluated applying the Kirby-Baüer method. Regarding the Escherichia coli strains, E. radiata and the mixture of E. radiata and E. globulus had a better inhibitory effect than antiseptics. E. globulus had a better effect against most Staphylococcus spp. compared to E. radiata. For both Gram-negative and Gram-positive strains tested, chlorhexidine gluconate had a better inhibitory effect than povidone-iodine. The antibacterial efficacy of essential oils highlights their potential to substitute or complement the use of antiseptics and so reduce resistance to antiseptics.

Inhibition of corrosion of an aluminum alloy by rosemary and eucalyptus extracted oils in 1M hydrochloric acid medium: an experimental and theoretical study.

In this study, we explored aluminum corrosion inhibition field of study in a 1M HCl solution, harnessing the power of essential oils extracted from rosemary and eucalyptus plants. Our exploration gives a comprehensive analysis of the pivotal factors that shape the corrosion inhibition process. Our scientific journey was marked by a deliberate and systematic approach, encompassing the utilization of gravimetric analysis (weight loss), electrochemical potentiodynamic polarization, and the sophisticated electrochemical impedance spectrometry (EIS) techniques. Our findings unveiled promising and nuanced outcomes, particularly in the area of the electrochemical technique. This method demonstrated remarkable inhibition efficiencies, ranging from 42% to an impressive 92% for rosemary essential oil and from 37 to 84% for eucalyptus essential oil. These results unveiled a dynamic relationship between essential oil concentration and inhibition efficiency, a revelation that further deepens our understanding of the corrosion inhibition process. The inhibition efficiency increased with higher concentrations of essential oil but decreased with elevated temperatures. Furthermore, our analysis traversed into the realms of potentiodynamic and thermodynamic insights. These analytical techniques unearthed the complex mechanisms at play, explaining the pathway followed by the studied inhibitors. They exhibited their prowess by forming protective films on the metal surface, acting as vigilant protectors against the relentless forces of corrosion. Complementing our experimental findings, our study of computational chemistry through density functional theory (DFT) unveiled remarkable insights. It elucidated the spontaneous adsorption process of inhibitor molecules onto the aluminum surface in the presence of H2O solvent. This computational harmony with our experimental results strengthened our confidence in the robustness of our findings. One of the key findings of this study was the superior inhibitory power of camphor in rosemary EO and β-myrcene in eucalyptus essential oil EO, respectively, attributed to the distinctive characteristics of the active sites found in each compound. The inhibitory effectiveness followed the order β-myrcene > camphor > borneol > α-pinene > bornyl acetate > p-cymene > 1,8-cineole. These compounds, notable for their distinct active sites, emerged as exceptional agents in the pursuit of effective corrosion inhibition.

Investigating the Effects of Dietary Supplementation of Eucalyptus Camaldulensis Essential Oil on Haemato-Biochemical Indices, Immune Response and Oxidative Stress of Weaned Rabbits

The aim of this experiment was to investigate the effects of dietary supplementation of Eucalyptus camaldulensis essential oil on haemato-biochemical indices, immune response and oxidative stress of weaned rabbits. Sixty healthy weaned cross bred male rabbits (4 weeks of age) with initial body weight of 460.1 ± 0.25 g were grouped based on their body weight into four treatments containing treatment 1 (T1) basal diet with no Eucalyptus camaldulensis oil (ECO), T2, T3 and T4 were fed basal diet with 200 mg, 400 mg and 600 mg/kg respectively in a completely randomized design. Feed and clean water was supplied ad libitum throughout the experiment which lasted for 56 days. All haematological parameters (pack cell volume, red blood cell, haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentrations, white blood cells and its differentials) were higher (P˂0.05) in T2, T3 and T4 relative to T1. Total protein, albumin, globulin, albumin/globulin ratio, cholesterol, aspartate transaminase, alanine transaminase and alanine phosphatase values were greater in ECO supplemented diets whereas urea nitrogen, creatinine, calcium, phosphorus, potassium, sodium and bicarbonate were influenced by the treatments. However, all values were within the optimal range for healthy rabbits. Immunoglobulins, melanodialdehyde, superoxide dismutase, glutathione peroxidase, catalase and total antioxidant capacity were higher (P˂0.05) in T2, T3 and T4 than in other diet. Result revealed that ECO can be supplemented up to 600 mg/kg without negatively affecting the performance and health status of rabbits.

Development of a polydimethylsiloxane–Eucalyptus essential oil antibacterial coating

Development of a polydimethylsiloxane–Eucalyptus essential oil antibacterial coating

Tunisian Eucalyptus essential oils: exploring their potential for biological applications

This study focuses on different chemo-types of Tunisian Eucalyptus essential oils (EOs) and their potential for controlling aphids, phytopathogenic fungi, weed germination and seedling growth. The EOs, obtained from Eucalyptus astringens (Maiden) Maiden and Eucalyptus lehmannii (Schauer) Benth. leaves through hydrodistillation, were analyzed using GC-MS. The chemical analysis revealed a significant presence of oxygenated monoterpenes (ranging from 41.0% to 83.0%), primarily 1,8-cineole (ranging from 30.5% to 58.5%), and oxygenated sesquiterpenes, mainly globulol (19.0%) for E. astringens. In contrast, α-pinene (7.0%) was the second most abundant chemical class for E. lehmannii. Statistical analysis demonstrated that both EOs were effective against aphids, fungi, and weeds based on their composition. E. lehmannii showed high efficacy against aphids, causing complete mortality in Aphis fabae Scopoli and an 87.28 ± 0.65% mortality rate in Aphis nerii Fonscolombe at a concentration of 0.6 mg/mL. E. astringens exhibited antifungal activity with consistent inhibitory effects exceeding 50.59 ± 0.87% against Fusarium oxysporum Schltdl., and Sclerotinia sclerotiorum (Lib.) de Bary displayed even higher susceptibility with an inhibition rate of 83.33 ± 1.10%. Similarly, E. lehmannii inhibited fungal growth by nearly 50%, with Fusarium culmorum Schltdl. exhibiting a minimum inhibition rate of 45.59 ± 0.71%. Both EOs also displayed significant herbicidal potential by impeding weed germination and seedling growth. Sinapis arvensis L. was particularly susceptible, with complete inhibition observed at a concentration of 2 mg/mL. Overall, these findings highlight the potential application of these Eucalyptus EOs for bio-control, underscoring their diverse characteristics.

Metabolite profiling of four Tunisian Eucalyptus essential oils and assessment of their insecticidal and antifungal activities

Aphids (Aphidoidea) and Fusarium spp. are widely recognized as destructive pests that cause significant damage to crops on a global scale. This study aimed to ascertain the chemical composition of essential oils (EOs) of four Tunisian Eucalyptus species and evaluate their toxicity against common aphids and phytopathogenic fungi.The EOs were obtained via hydrodistillation and subsequently analyzed using GC-MS. The chemical composition analysis revealed the presence of five distinct chemical classes in the EOs: monoterpene hydrocarbons (3.8–16.7 %), oxygenated monoterpenes (5.5–86.0 %), sesquiterpene hydrocarbons (0.2–2.2 %), oxygenated sesquiterpenes (4.2–86.7 %), and non-terpene derivatives (0.1–14.1 %).Hierarchical clustering analysis (HCA) and principal component analysis (PCA) of the Eucalyptus leaf EOs highlighted significant differences among them, leading to the generation of distinct HCA clades representing at least twelve major components.The statistical analysis clearly demonstrated a dose-response relationship, indicating the impact of the tested EOs on the growth of insects and fungal mycelium. The observed effects varied due to the variability in the chemical compositions of the EOs.Notably, among the EOs tested, Eucalyptus lesoufii Maiden exhibited particularly potent effects against the targeted insect and fungal species. This research contributes to the ongoing exploration of natural alternatives to chemical pesticides, providing further insights for potential industrial applications. It underscores the versatility of these EOs and their potential as valuable candidates in strategies for pest and disease management.

Sulfur nanocomposites with insecticidal effect for the control of Bactericera cockerelli.

The purpose of this research was to synthesize nanocomposites consisting of sulfur nanoparticles coated with eucalyptus and rosemary essential oils to determine the insecticidal effect in the control of nymphs of paratrioza (Bactericera cockerelli (Sulc) (Hemiptera: Triozidae)) in potato crops. A solution of thiosulfate was reduced to elemental sulfur, and the sulfur nanoparticles were coated with eucalyptus and rosemary essential oils with the three concentrations of 0.25%, 0.5%, and 0.75%. The samples were characterized by UV-visible spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. The insecticidal efficacy of the nanocomposites was evaluated in the entomology laboratory 24, 48, and 72 h after application. Furthermore, efficacy was compared to the commercial insecticide thiamethoxam (0.25%) and a control. The results show that eucalyptus nanocomposites with oil concentrations of 0.25%, 0.5%, and 0.75% and rosemary nanocomposites with an oil concentration of 0.5% have an insecticidal efficacy of 100% for the control of insect nymphs 24 h after application. The insecticidal efficacy of rosemary nanocomposites with oil concentrations of 0.25% and 0.75% increases over time and reaches 100% at 24 and 72 h, respectively. The synthesized nanocomposites are more effective in controlling nymphs of paratrioza than the commercial insecticide thiamethoxam; thus, they could be used for the development of new insecticides.

PSVII-14 Reduction in Heart Rate Variability Parameters in Horses Treated with a Mixture of Lavender and Eucalyptus Essential Oil

Abstract Routine medical examinations can produce stress which can negatively impact the health and well-being of horses. Heart rate variability (HRV) is a non-invasive and inexpensive method to measure the balance between sympathetic and parasympathetic nervous system activity, which can help identify stress in horses. This study examined the effect of a combination of lavender and eucalyptus essential oil on stress responses in horses undergoing a routine medical exam. After a five-minute stall rest (baseline reading) data were collected in three, five-minute intervals (walk to and enter stock, medical exam, and recovery in stall). This study utilized a switch-back design where each horse (n = 10) received both treatments on different dates. The treatment groups received lavender (20%) and eucalyptus essential oil (5%) dissolved in petroleum jelly and virgin sunflower oil applied to inner nostrils. The control treatment consisted of only petroleum jelly and virgin sunflower oil applied to inner nostrils. The root mean square of the successive differences of heartbeats (RMSSD) was significantly reduced (P < 0.05) when horses were treated with essential oils while walking to stocks (51.7 ± 3.7), during the medical exam (50.5 ± 4.9), and during the recovery period (64.1.9 ± 5.7) compared with control treatment, to stocks (36.1 ± 4.4), the medical exam (39.0 .± 4.5), and during the recovery period (49.7 ± 5.5). The measured SD1 (parasympathetic) was significantly greater (P < 0.008) at walk to stocks in horses treated with essential oils (37.2 ± 1.9) compared with control treated (30.3 ± 3.1). The measured SD2 (sympathetic) was significantly less (P < 0.008) at walk to stocks in horses treated with essential oils (62.8 ± 1.9) compared with control treated (69.7 ± 6.8). The ratio of SD1/SD2 was significantly less (P < 0.008) at walk to stocks in horses treated with essential oils (1.7 ± 0.17) compared with control treated (2.4 ± 0.26). The high frequency percent (HF%) was also greater (P < 0.04) at walk to stocks in horses treated with essential oils (39.6 ± 4.9) compared with control treated (26.0 ± 4.1). The standard deviation of RR Interval (SDNN) values were increased (P < 0.03) in horses treated with essential oils during walking to stalks (50.8 ± 1.9), the medical exam (56.7 ± 5.0), and the recovery period (72.4 ± 12.9) compared with the control treatment, to stalks (44.5 ± 5.2), medical exam (44.0 ± 4.5), and during the recovery period (54.6 ± 6.2). The results of this study indicate that lavender and eucalyptus oil could be an effective means of reducing short-term stress in horses. The findings of this study can help develop more effective and humane management strategies for horses.

Cumin and eucalyptus essential oil standardization using fractional distillation: Data-driven optimization and techno-economic analysis

Cumin and eucalyptus essential oils (EOs) are among the most important and widely used EOs with a broad range of applications in the pharmaceuticals, cosmetics, and food industries. The seeds and leaves of cumin (Cuminum cyminum) and eucalyptus (Eucalyptus globulus) plants are processed with extraction techniques to retrieve their EOs, yet certain product specifications need to be met to achieve a high-quality product. Based on the International Organization for Standardization (ISO), the essential oils of cumin and eucalyptus should contain certain amounts of cuminaldehyde and 1,8-cineole to be of acceptable quality. In this study, we design and optimize a dynamic fractional distillation process that enriches cumin and eucalyptus EOs to the ISO standards, with concentrations of 42% cuminaldehyde and 80% of 1,8-cineole achieved for each EO respectively. The dynamic model of this process is simulated via Aspen Plus using data from a pilot-scale fractional distillation unit, and the operating conditions that minimize the operational cost in the simulated environment are identified using the NOMAD algorithm. The optimization results show that the operating cost of standardization processes for cumin and eucalyptus EOs are $0.688/batch and $0.6973/batch, with process efficiencies of 69.56% and 59.77%, respectively. Furthermore, the techno-economic analysis for these two standardization processes showed that the total annualized cost was approximately $510,600 for both processes.

Determination of the constituents, inhibition microorganisms tested and microorganisms in pork of the essential oil from Eucalyptus citriodora Hook leaves

The objective of this study is to determine all the constituents, inhibition microorganisms tested and microorganisms in pork of the essential oil from Eucalyptus citriodora Hook leaves. The essential oil from Eucalyptus citriodora Hook leaves in Vinh Phuc, was obtained by steam distillation and dried with Na2SO4. By Gas chromatography-mass spectrometry (GC-MS) method, seventeen components in the essential oil of Eucalyptus citriodora Hook leaves were predicted by comparing their retention times and molecular weights with the standards. In particular, among thirteen hydrocarbons, monoterpene accounts for 1.74%, and sesquiterpene accounts for 22.30%; Among the 14 oxidized hydrocarbon components: 24.72% alcohols, 5.95% ketones, 29.84% aldehydes, and 14.26% esters. The results showed that the essential oil of Eucalyptus citriodora Hook leaves possessed antibacterial activity against all of the five microorganisms tested. Among them, the antibacterial activity against Bacillus subtilis, Salmonella enterica, and Lactobacillus fermentum was the highest. Therefore, based on the microbiological criteria and to reduce the cost during the preservation process, the content of essential oil of Eucalyptus citriodora Hook leaves of 0.4% per pork weight was selected as the basis for building a process to preserve pork with essential oil of Eucalyptus citriodora Hook leaves at 6oC. This is the scientific basis for the application of essential oil Eucalyptus citriodora Hook leaves in food processing and preservation, which is very necessary with high scientific and practical significance.

Chemical Composition, Antibacterial Properties, and Anti-Enzymatic Effects of Eucalyptus Essential Oils Sourced from Tunisia.

This study was conducted to examine the chemical composition of the essential oils (EOs) from six Tunisian Eucalyptus species and to evaluate their anti-enzymatic and antibiofilm activities. The EOs were obtained through hydro-distillation of dried leaves and subsequently analyzed using GC/MS. The main class of compounds was constituted by oxygenated monoterpenes, particularly prominent in E. brevifolia (75.7%), E. lehmannii (72.8%), and E. woollsiana (67%). Anti-enzymatic activities against cholinesterases, α-amylase, and α-glucosidase were evaluated using spectrophotometric methods. Notably, the E. brevifolia, E. extensa, E. leptophylla, E. patellaris, and E. woollsiana EOs displayed potent acetylcholinesterase (AChE) inhibition (IC50: 0.25-0.60 mg/mL), with E. lehmannii exhibiting lower activity (IC50: 1.2 mg/mL). E. leptophylla and E. brevifolia showed remarkable α-amylase inhibition (IC50: 0.88 mg/mL), while E. brevifolia and E. leptophylla significantly hindered α-glucosidase (IC50 < 30 mg/mL), distinguishing them from other EOs with limited effects. Additionally, the EOs were assessed for their anti-biofilm properties of Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The E. extensa EO demonstrated the main antibiofilm effect against E. coli and L. monocytogenes with an inhibition > 80% at 10 mg/mL. These findings could represent a basis for possible further use of Eucalyptus EOs in the treatment of human microbial infections and/or as a coadjutant in preventing and treating Alzheimer's disease and/or diabetes mellitus.

Essential oils in broiler chicken diets as antimicrobial agents: Systematic review

The search for alternative ingredient options in the animal diet that have antimicrobial activity is due to many factors, such as pathogens increasing resistance and the presence of antibiotic residues in animal products consumed by humans. Therefore, there is a rising demand for natural additives that do not interfere with animal development or human health. Here, we compare studies on the use of essential oils as antimicrobial agents in broiler chicken diets. First, 90 papers were found using the key words “broilers”, “antimicrobial”, and “essential oils”. The second step was to select the papers according to the scales of Jadad and Medeiros and Stein, where six remaining researchers were selected to describe the antimicrobial activity of essential oils in response to enteric pathogens. Essential oils (EOS) have antimicrobial activity against different pathogens, such as E. coli, S. Enteritidis, S. Heidelberg and C. perfringens, and are considered alternatives to antibiotics used in animal production. The EOs that showed the greatest effectiveness were oregano essential oil (EO), cinnamaldehyde and thymol concentrates; when used together with additives such as sodium butyrate and xylanase, there was better antimicrobial action and improved animal performance. Ginger and carvacrol EOS also demonstrated antimicrobial activities, as did thymol, cinnamaldehyde and eucalyptus EO concentrates, but studies on the specific action of plant species that produce EOS for certain pathogens are still lacking; thus, the topic lacks an ongoing study addressing the addition of EOS in the feed of poultry production.

Anti-oomycete activities from essential oils and their major compounds on Phytophthora infestans

Botanicals are various plant-based products like plant extracts or essential oils. Anti-fungal activities of selected essential oils were tested on the pathogen causing potato and tomato late blight (Phytophthora infestans). Tests to evaluate anti-oomycete activities of commercial essential oils and their major compounds were carried out in vitro in microplate in liquid media. Anti-oomycete activities on Phytophthora infestans strain were obtained from essential oils/major compounds: Eucalyptus citriodora/citronellal; Syzygium aromaticum (clove)/eugenol; Mentha spicata/D-Carvone, L-Carvone; Origanum compactum/carvacrol; Satureja montana (savory)/carvacrol; Melaleuca alternifolia (tea tree)/terpinen-4-ol, and Thymus vulgaris/thymol. As an active substance of mineral origin, copper sulfate was chosen as a control. All selected essential oils showed an anti-oomycete activity calculated with IC50 indicator. The essential oils of clove, savory, and thyme showed the best anti-oomycete activities similar to copper sulfate, while oregano, eucalyptus, mint, and tea tree essential oils exhibited significantly weaker activities than copper sulfate. Clove essential oil showed the best activity (IC50 = 28 mg/L), while tea tree essential oil showed the worst activity (IC50 = 476 mg/L). For major compounds, three results were obtained: they were statistically more active than their essential oils (carvacrol for oregano, D- and L-Carvone for mint) or as active as their essential oils sources (thymol for thyme, carvacrol for savory, terpinen-4-ol for tea tree) or less active than their original essential oils (eugenol for clove, citronellal for eucalyptus). Microscopical observations carried out with the seven essential oils showed that they were all responsible for a modification of the morphology of the mycelium. The results demonstrated that various essential oils show different anti-oomycete activities, sometimes related to a major compound and sometimes unrelated, indicating that other compounds must play a role in total anti-oomycete activity.