Clove Oil Research Articles

Production of biodiesel and analysis of exhaust particulate emissions and metal concentration of lubricant oil of the compression ignition engine

In this research, biodiesel fuel is produced using potassium hydroxide (KOH) as a catalyst and methanol as a co-solvent through the transesterification process. The analysis of particulate matter emissions from a compression ignition (CI) engine with pure diesel fuel (D100), biodiesel-mixed (B30), and clove oil (CL3000 ppm) was carried out. The findings obtained revealed 5.27% reduction of particulate matter in biodiesel-blended fuel, and furthermore, when clove was added to the biodiesel-blended fuel, 11.61% reduction of particulate matter was observed as compared to pure diesel. It may be due to the higher oxygen ratio present in clove oil. The engine was run for 100 h on each fuel sample, and the data were taken and tested per 25 h for elemental analysis. The results manifest that the metal concentration found different elements in lubricant oil, i.e., lead (51.84), (24.89%), and (23.255%); copper (47.41%), (28.71%), and (23.86%); nickel (37.88%), (32.32), and (29.78%); and cadmium (46.12), (29.87%), and (24.01%) in diesel, biodiesel-blended fuel, and biodiesel blended with clove oil, respectively. This study found better results for engine life, which shows the lower metal concentration in biodiesel-blended fuel and clove oil than diesel. Furthermore, the fuels investigated in this research can reduce the wear of engine parts because biodiesel and clove oil contain a high oxygen ratio. Moreover, it has been found that biodiesel and clove oil as an antioxidant have a positive impact on noise emission levels for the CI engine.

The Use of Biopolymers as a Natural Matrix for Incorporation of Essential Oils of Medicinal Plants.

The benefits of using biopolymers for the development of films and coatings are well known. The enrichment of these material properties through various natural additions has led to their applicability in various fields. Essential oils, which are well-known for their beneficial properties, are widely used as encapsulating agents in films based on biopolymers. In this study, we developed biopolymer-based films and tested their properties following the addition of 7.5% and 15% (w/v) essential oils of lemon, orange, grapefruit, cinnamon, clove, chamomile, ginger, eucalyptus or mint. The samples were tested immediately after development and after one year of storage in order to examine possible long-term property changes. All films showed reductions in mass, thickness and microstructure, as well as mechanical properties. The most considerable variations in physical properties were observed in the 7.5% lemon oil sample and the 15% grapefruit oil sample, with the largest reductions in mass (23.13%), thickness (from 109.67 µm to 81.67 µm) and density (from 0.75 g/cm3 to 0.43 g/cm3). However, the microstructure of the sample was considerably improved. Although the addition of lemon essential oil prevented the reduction in mass during the storage period, it favored the degradation of the microstructure and the loss of elasticity (from 16.7% to 1.51% for the sample with 7.5% lemon EO and from 18.28% to 1.91% for the sample with 15% lemon EO). Although the addition of essential oils of mint and ginger resulted in films with a more homogeneous microstructure, the increase in concentration favored the appearance of pores and modifications of color parameters. With the exception of films with added orange, cinnamon and clove EOs, the antioxidant capacity of the films decreased during storage. The most obvious variations were identified in the samples with lemon, mint and clove EOs. The most unstable samples were those with added ginger (95.01%), lemon (92%) and mint (90.22%).

Development of Oral Microemulsion Spray Containing Pentacyclic Triterpenes-Rich Centella asiatica (L.) Urb. Extract for Healing Mouth Ulcers.

Several publications have shown that Centella asiatica (L.) Urb. and its active constituents (pentacyclic triterpenes) are effective in wound healing. The pentacyclic triterpenes-rich C. asiatica extract (PRE) was prepared following a previous study by microwave-assisted extraction (MAE) and fractionation with macroporous resin. This method provided the pentacyclic triterpene content in the extract up to 59.60% w/w. The PRE showed potent anti-inflammatory activity by inhibiting nitric oxide (NO) production with an IC50 value of 20.59 ± 3.48 μg/mL and a potent fibroblast proliferative effect (165.67%) at concentrations of 10 μg/mL. The prepared microemulsion consisted of a water: oil: surfactant mixture of 2: 2: 6, using coconut oil: clove oil (1:1) as the oil phase and Tween 20: Span 20 (2:1) as the surfactant mixture and 1.0, 2.5, and 5.0% PRE. Cell proliferation, migration, and collagen production of the microemulsion base and microemulsions containing 1.0%, 2.5%, and 5.0% PRE were evaluated. The results revealed that the microemulsion containing 1% PRE had the highest proliferation effect (136.30 ± 3.93% to 152.65 ± 3.48% at concentrations of 10 μg/mL), migration activities (100.00 ± 0.0% at 24 h), and collagen production in human dermal fibroblast (HDF) and human gingival fibroblast (HGF) cells when compared with other formulations or blank. Moreover, the anti-inflammatory activity of microemulsions containing 1% PRE was slightly lower than standard indomethacin. Anti-inflammation of the microemulsion containing PRE exhibited a dose-dependent trend, while 5% PRE was more potent than the standard drug. Considering the potent wound-healing activities and the good anti-inflammatory activity of the microemulsion containing PRE, the microemulsion with 1% PRE was identified as the most suitable oral spray formulation for oral ulcer treatment.

Effects of Supplementing Quails' (Coturnix japonica) Diets with a Blend of Clove (Syzygium aromaticum) and Black Cumin (Nigella sativa) Oils on Growth Performance and Health Aspects.

In an attempt to discover a safe growth promoter and partial alternative for antibiotics, this existing study explores the efficacy of using assorted levels of cold-pressed oil mixtures consisting of 1:1 clove and black cumin (Nigella sativa) oils (CLNS) against the indices of growth and carcass traits, as well as blood components of growing Japanese quails. In a complete randomized design, three hundred growing unsexed Japanese quails (one week of age) were included in this experiment. The treated groups were as follows: (1) control basal diet (CLNS0), (2) basal diet + 1.50 mL CLNS/kg diet (CLNS1.5), and (3) basal diet + 3.00 mL CLNS/kg diet (CLNS3). The results showed that supplementing the diet with a 3.00 mL CLNS/kg diet insignificantly improved body weight (BW) compared with the CLNS0 and CLNS1.5 groups. A significantly (p < 0.05) higher feed intake and feed conversion ratio-FCR- (deterioration of feed conversion) were reported after the addition of CLNS. Feeding the quails on a 3.00 mL CLNS/kg enriched-diet yielded superior values of dressing percentage, carcass yield, and breast and thigh relative weights compared to other groups. A significant decline was noticed in creatinine and BUN levels in birds fed a 1.50 and 3.00 mL CLNS/kg diet compared with the CLNS0 group The liver enzymes and total bilirubin activities showed insignificant effects in quails fed CLNS-enriched diets. The total protein and globulins concentrations presented a significant augment in quails that received CLNS. The antiradical activity of CLNS supplementation showed increases in hepatic reduced glutathione (GSH) activity and the levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, glutathione S transferase (GST), and glutathione reductase (GR) in birds. The concentration of MDA in hepatic homogenates that received CLNS-diets was significantly decreased compared with the control quails. These findings clarified that the dietary inclusion of CLNS can enhance the growth performance and antioxidative status of growing Japanese quails.

High-Pressure-Homogenized Clove and Thyme Oil Emulsions: Formulation, Stability, and Antioxidant Capacity

High-Pressure-Homogenized Clove and Thyme Oil Emulsions: Formulation, Stability, and Antioxidant Capacity

Evaluation of Essential Oils as Spatial Repellents Against Aedes aegypti in an Olfactometer.

Spatial repellents are becoming an integral part of the integrated mosquito management and are considered another tool to prevent mosquito-borne diseases. They are also gaining attention as a potential disease transmission breaking strategy. Current vector control practices are losing their viability due to resistance development in arthropods to synthetic pesticides. Economic feasibility of developing natural products is driving towards search for natural products as spatial repellents evidenced by increase in number of their studies. Different volumes (0.0625, 0.125, 0.25, 0.5 ml) of clove oil, eucalyptus oil, geraniol, Immortelle oil, lemongrass oil, and RepelCare (mixture of turmeric oil and eucalyptus oil) were evaluated for their repellency against Aedes aegypti, replicating each test 5 times. Biogents lure and fresh air were used as control. The evaluations were conducted in a True Choice olfactometer by passing air carrying 2 vapors from 2 different products, i.e., an attractant, repellent, or clean air, through 2 chambers and providing mosquitoes an option to move to the chamber of their choice. For each run, 24-h-starved 15-20 female Ae. aegypti were released into the mosquito release chamber and number of mosquitoes in the 2-choice chambers and the mosquito release chamber were counted after 15 min and recorded. The difference in mosquitoes between 2 chambers indicated presence or absence of repellency. All the natural oils and RepelCare provided ≥70% repellency, except for Immortelle oil which had no repellency. All repellents tested except Immortelle and lemongrass oils showed increase in repellency with increase in application volume. However, minimum application volume to be effective was different for each oil. Lemongrass is the only oil which showed a peak at 0.125-ml volume.

Fabrication of multifunctional materials based on chitosan/gelatin incorporating curcumin-clove oil emulsion for meat freshness monitoring and shelf-life extension

A new multifunctional film with active and intelligent effects was developed by incorporating curcumin-clove oil emulsion into natural materials. The basic properties, functional characteristics, and pH/NH3-sensitivity of films were investigated, and then these films were applied to extend shelf-life and monitor freshness of meat. Curcumin solution and emulsion illustrated significant color variations at different pH values. The incorporation of emulsion improved the UV–vis barrier and water resistance properties of films, which blocked most of UV-light and its water contact angle reached 100.03°. Meanwhile, the films had stronger mechanical strength and higher thermal stability, with elongation at break reaching 79.18 % and the maximum degradation temperature rising to 316 °C. Moreover, emulsion made films have a slow-release effect on clove oil, which not only enhanced the antioxidant property but also significantly improved their antibacterial activity. Additionally, the multifunctional films presented a significant color response to acidic/alkaline environments over a short time interval and could be easily identified by naked eyes. Finally, the films effectively extended the shelf-life of fresh meat by 3 days at 4 °C and visually monitored freshness through color changes in real-time. This knowledge provides insights and ideas for the development of novel food packaging with both active and intelligent functions.

In silico ATP Synthase Inhibition Activity and Antibacterial Activity of Selected Essential Oil against Escherichia coli and Resistant Acinetobacter baumannii

The rise in the resistant strains has ignited the investigation of the ability of these essential oils to have an effect against them. The aim of this study was to investigate the antibacterial activity of clove oil, oregano oil and tea tree oil against Escherichia coli and resistant patient isolate Acinetobacter baumannii. Ciprofloxacin was used as standard and DMSO at 1 % was the negative control. To understand the inhibitory action on ATP synthase, docking analysis was done by using Autodock ver. 4.2.6. The study found out that essential oils had potent antibacterial activity against both E. coli and A. baumannii as all the essential oils recorded zones above 15 mm against E. coli and above 20 mm against A. baumannii. Tea tree oil had the highest activity among the three essentials against E. coli with 21.000±0.00 mm and against A. baumannii 28.500±0.500 mm respectively. These results support the antibacterial activity of essential oils. Docking analysis confirmed the ability of active constituents of selected essential oils to inhibit ATP synthase enzyme which is a crucial drug target in antimicrobial activity. Natural products have been at the center stage in the research for alternative agents with antibacterial agents.

Effect of hydroxypr1opylation on physical properties, antifungal and mycotoxin inhibitory activities of clove oil emulsions coated with chitosan

Fusarium graminearum is one of the most common fungi infecting grains and the production of mycotoxin, deoxynivalenol (DON), poses a serious threat to human and livestock health. Chitosan coated emulsion can be used as a highly effective antifungal agent. However, the poor solubility of chitosan leads to a longer ultrasonic time for preparing emulsion. In our work, hydroxypropyl chitosan with better water dispersion was prepared and used as a coating for clove oil emulsion, and the effect of hydroxypropylation on the physical properties, antifungal and mycotoxin inhibitory activities of chitosan coated clove oil emulsion was investigated. Compared with unmodified chitosan coated clove oil emulsion, hydroxypropyl chitosan coated clove oil emulsion had smaller particle size, lower viscosity, and its maximum reduction of the mycelial diameter and the minimum fungicidal concentration was 35% and 50%, respectively. These results indicated that hydroxypropylation could improve the physical properties and antifungal activity of chitosan coated clove oil emulsion to a certain extent. Surprisingly, after being cultured in barley medium for 7 d, the maximum reduction of DON and ergosterol accumulation was 87% and 86% respectively, showing that hydroxypropyl chitosan coated clove oil emulsion can inhibit the production of DON by mitigating the growth of F. graminearum. Moreover, clove oil emulsions coated with high molecular weight hydroxypropyl chitosan showed a stronger inhibitory effect on the accumulation of DON and ergosterol. This work can provide a reference for mitigating fungal growth and mycotoxin production in food by essential oil emulsions.

Chemical composition of essential oils from leaf and bud of clove and their impact on the antifungal and mycotoxin inhibitory activities of clove oil-in-water nanoemulsions

The impacts of clove oil (CO) type on the physicochemical properties, antifungal activities, and mycotoxin inhibitory efficacies of CO-in-water nanoemulsions were investigated. By blending 25 wt% of clove oil with 75 wt% of corn oil in oil phase (5 wt%), clove bud oil (CBO)-in-water nanoemulsion and clove leaf oil (CLO)-in-water nanoemulsion showed highly physical stable with the mean particle size < 170 nm. The concentration of major chemical constituents such as eugenol and caryophyllene in nanoemulsion maintained constant during storage time. The antifungal activities of nanoemulsions against two Fusarium graminearum isolates were strongly dependent on the CO concentration. For instance, CLO nanoemulsion displayed an appreciable higher antifungal activity compared to CBO nanoemulsion at a lower CO concentration. Both nanoemulsions could effectively inhibit fungal mycelial growth and spore germination , but in a different antifungal mode of actions. Regarding the mycotoxin inhibitory efficacy, both CO nanoemulsions could effectively inhibit mycotoxin production including deoxynivalenol (DON) and its derivatives: 3-acetyl-deoxynivalenol (3ADON), 15-acetyl-deoxynivalenol (15ADON). • Chemical composition of clove bud oil (CBO) and clove leaf oil (CLO) showed differences. • The physicochemical stability of clove oil (CO)n nanoemulsions were fabricated. • Antifungal activity of CO nanoemulsions was in a dose-dependent manner. • Different antifungal modes of actions between CBO and CLO was observed. • Both CO nanoemulsions could effectively inhibit mycotoxin production.

Improvement of the shelf life of grey mullet (Mugil cephalus) fish steaks using edible coatings containing chitosan, nanochitosan, and clove oil during refrigerated storage

The effects of edible coatings made of chitosan, or chitosan nanoparticles, and their combinations with clove oil on the physical, chemical, microbiological, and sensory properties of grey mullet (Mugil cephalus) steaks during refrigerated storage (4 °C) for 24 days were evaluated. The data indicated that metrics for all of these characteristics were improved significantly (P ≤ 0.05) in coated fish steak samples compared to the control sample. The coated steaks texture values were higher than those of control sample through storage time with nanochitosan coating containing clove oil having best value 2.51 kg/cm2 among tested samples at the end of storage period. However, pH values of coated samples were lower, a good indicator, than corresponding one of the control (6.46) with nanochitosan coatings with or without clove oil showed low mean values (6.11–6.13). Similar trend regarding chemical indices, i.e. total volatile basic-nitrogen, trimethylamine, peroxide, and thiobarbituric acid reactive substances values for samples coated with nanochitosan with or without clove oil giving better lower values than control or other treatments. Also, the coating delayed microbial (aerobic plate count, psychrotrophic bacteria, yeasts and molds, and total coliform bacteria) growth during the refrigeration storage period, and coated samples produced better results compared to the control sample. Sensory evaluations showed that the treatment enhanced the scores of fish steak samples compared to the control. The results showed that a nanochitosan coating with clove oil was the best treatment prolonged the shelf life of mullet steaks and efficiently maintained the quality attributes to an acceptable level during refrigerated storage for 24 days. Thus, these findings can be bases for producer to provide consumers with fresh fish steaks with good shelf life at refrigerated temperature for up to 24 days.Graphical

Antibacterial and anti-biofilm activity of cinnamon and clove oils against uropathogens

Antibacterial and anti-biofilm activity of cinnamon and clove oils against uropathogens

Oil mediated green synthesis of nano silver in the presence of surfactants for catalytic and food preservation application

Abstract The present study details the green synthesis of silver nanoparticles using clove oil as a reducing and stabilizing agent. Cationic, anionic, nonionic and zwitterionic surfactants were introduced to study the change in size, shape, and morphology of nanoparticles. The nanoparticles were characterized using different techniques. The nanoparticles had shown specific surface Plasmon resonance band with absorbance between 380 and 385 nm. The X-ray diffraction study revealed that the nanoparticles are composed of spherical cubic crystals with average size between 136 and 180 nm while Dynamic Laser scattering (DLS) studies revealed an effective diameter of 82 nm and polydispersity index of 0.005. Thermogravimetric analysis suggested that the particles are stable even at 600 °C. All the samples presented good antibacterial and antifungal efficacies against Staphylococcus aureus, Klebsiella pneumonia and Candida albicans and good catalytic activities for the degradation of fast green and Allura red dyes. Further, thin edible films of the nanoparticles were prepared using sodium alginate for food preservation. The films were coated on fruits and vegetables for extending their shelf life to cope with demand and supply gap.

Recent Progress of Bioactivities, Mechanisms of Action, Total Synthesis, Structural Modifications and Structure-activity Relationships of Indole Derivatives: A Review.

Indole (2,3-benzopyrrole) containing a pyrrolyl ring possesses the characteristic of electron- rich aromatic compounds. Indole occurs in the oil of jasmine and cloves and coal tar. Additionally, it is also present as a putrefaction product from animals' intestines. Notably, indole and its derivatives exhibit a wide range of biological properties, such as anti-Alzheimer's disease, anti-cancer, antibacterial, anti-inflammatory, anti-human immunodeficiency virus (HIV), anti-diabetic, antituberculosis, anti-oxidant, anti-coronavirus, and antifungal activities. In this mini-review, recent advances in biological activities, mechanisms of action, total synthesis, structural modifications, and structure-activity relationships of indole and its derivatives from 2018 to 2020 are described. We hope the present paper can pave the way for future design, development, and application of indole derivatives as potent drugs.

Sustainable Development of Chitosan Encapsulated Clove Oil Microstructures and Impregnation Thereof onto Cellulosic Fabric for Multipurpose Textile

Sustainable Development of Chitosan Encapsulated Clove Oil Microstructures and Impregnation Thereof onto Cellulosic Fabric for Multipurpose Textile

Effect of Medium on the Activity of Eugenol: A Mini-Review

Abstract: The role of essential fatty acids is vital in the life of a human being. The lack of essential fatty acids causes various diseases, such as cardiovascular, inflammatory bowel, and obesity. Although synthetic antioxidants have already been used, nowadays, the demand for natural antioxidants has increased mainly because of the adverse effects of synthetic antioxidants. Spices are widely used in this context as a source of natural antioxidants. It has been observed that they also act as pro-oxidants. This review aims to evaluate the fundamental reason for the different activities of the spices by studying the example of eugenol, a principal phenolic constituent of clove oil. The chemistry concerning the mechanism to display antioxidant and pro-oxidant activity is currently being reviewed. The isomerization of eugenol to isoeugenol plays a key role in exhibiting dissimilar behaviour of the eugenol. Under the polar medium, isomerization of eugenol does not take place, and it acts as an antioxidant. However, in the non-polar medium, eugenol isomerizes to isoeugenol and displays a pro-oxidant effect. In the basic medium, eugenol isomerizing to isoeugenol undergoes degradation. Hence, to utilize the beneficial activity of eugenol, it should be present in a polar or acidic medium. It can be concluded from this review article that the structural form of any molecule plays a major role in utilizing its activity and is also dependent on the medium. Hence, the medium also performs a vital role in influencing the activity of any molecule.

Investigation of the Physical Properties and Droplet Combustion Analysis of Biofuel from Mixed Vegetable Oil and Clove Oil

The study of vegetable oil used as fuel in conventional engines leads to problems like the low volatility and high viscosity. This research aims to evaluate the droplet combustion characteristics that correlated with the density, viscosity, and the flash point of the biofuel from mixed vegetable oil with clove oil. Biofuels used in research are Jatropha Oil (CJO), Kapok Oil (KSO), Coconut oil (CCO), and all biofuel mixed with clove oil in 5% basis volume. Fuel properties that tested both biofuel and fuel mixture using the ASTM method are density (ASTM D1298), viscosity (ASTM D445), The flash point (ASTM D93). The droplet combustion experiment used suspended droplets placed in the junction of the K-type thermocouple and the Ni-Cr wire (as the coil heater) to heat the droplet until the combustion occurred. The result indicates that adding 5% clove oil in biofuel creates higher density, the viscosity decreases until 10%, and the flash point decrease to 30%. Droplet combustion results that adding 5% clove oil creating a more complete combustion process in CCO than KSO and CJO. Higher viscosity in KSO and CJO leads to eugenol and terpene (clove oil compound) trapping in the fuel droplet. Due to eugenol and terpene having great volatility, they are evaporating rapidly leading to secondary atomization and micro-explosion phenomena.

Chemical Characterization of Clove, Basil and Peppermint Essential Oils; Evaluating Their Toxicity on the Development Stages of Two-Spotted Spider Mites Grown on Cucumber Leaves.

The two spotted spider mite (TSSM), Tetranychus urticae Koch, is a cosmopolitan mite. It rapidly reproduces and can develop resistance to chemical pesticides. This study aims to evaluate the toxicity and acaricidal activity of three essential oils from basil, clove, and peppermint against T. urticae reproduction, which is grown on three cucumber cultivars, Chief (SC 4145), Raian (CB898), and Toshka (SC 349), under laboratory conditions at 27 + 3 °C and 70 + 5% RH. GC-MS characterized the volatile oils of basil, clove, and peppermint. Methyl cinnamate, eugenol, and menthol were the main essential oils in basil, clove, and peppermint, respectively. The results indicated significant differences in the duration of development between T. urticae feeding on the three cucumber cultivars (p ≤ 0.05), including eggs, protonymph, and deutonymph time. The Toshka (SC 349) cultivar recorded the lowest developmental time. The longevity period exhibited the same trend with non-significant differences between Raian (CB898) and Toshka (SC 349). Moreover, the lethal concentration (LC50) and LC90 values in tested essential oils (EOs) showed that clove EOs were the most toxic. In contrast, basil and peppermint EOs were the least effective, and immature stages were more sensitive to EOs than adult stages. The infected Toshka (SC 349) discs treated with essential oils and abamectin under in vitro conditions indicated that clove oil is comparable to abamectin regarding its effect on the egg numbers (18.7 and 17.6 egg), immature development time, longevity, life span, and life cycle (20.6 and 20.8 days) of T. urticae. We conclude that the resistant cultivation of cucumber plants can be recommended in integrated pest management programs. The most effective of the tested oils, clove EOs, should be used as alternatives to pesticides to control T. urticae in the protected cultivation of cucumbers.

Inactivation of Clostridium Spores in Honey with Supercritical CO2 and in Combination with Essential Oils

The presence of tens of Clostridium botulinum spores per gram of honey can cause infantile botulism. Thermal treatment is insufficient to inactivate these resistant forms. This study explored the effectiveness of supercritical CO2 (scCO2) on its own and combined with lemon (LEO), clove (CLEO), and cinnamon (CEO) essential oils on the inactivation of Clostridium sporogenes (CECT 553) as a surrogate of Clostridium botulinum. In water, the degree of inactivation at 10 MPa after 60 min increased with the increasing temperature, reducing the population by 90% at 40 °C and by 99.7% at 80 °C. In contrast, when applied to honey, scCO2 did not inactivate Clostridium spores satisfactorily at temperatures below 70 °C, which was related to the protective effect of honey. Meanwhile, scCO2 modified with CEO (&lt;0.4% mass) improved the inactivation degree, with a 1.3-log reduction achieved at 60 °C. With this same mixture, a reduction of 3.7 logs was accomplished in a derivative with 70% moisture. Honey was very sensitive to the temperature of the applied CO2. The obtained product could be used as a novel food, food ingredient, cosmetic, or medicine.

Antibiotic resistance profiles and activity of clove essential oil (Syzygium aromaticum) against Pseudomonas aeruginosa isolated of canine otitis.

Pseudomonas aeruginosa is often isolated from acute and chronic otitis and deep pyoderma in dogs. The increase in bacterial resistance to antibiotics induced the need for alternative therapies to treat infections, with an emphasis on essential oils (EOs). This study aimed to investigate clove oil's in vitro bactericidal action as a therapeutic alternative against strains of P. aeruginosa isolated from canine otitis. The antibacterial activity of clove oil was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth microdilution technique in 96-well plates. Serial concentrations of 10-0.31% of the oil were used, equivalent to 104.5-3.26 mg/mL. The susceptibility of isolates to different classes of antibiotics was determined by the disk diffusion technique using 20 antibiotics belonging to eight classes. Isolates resistant to at least one antibiotic of three different classes were considered multidrug-resistant (MDR). A high occurrence of resistance was observed for three antibiotics belonging to the cephalosporin classes (cefadroxil, cephalexin, and ceftriaxone), namely, sulfamethoxazole + trimethoprime, doxycycline, and enrofloxacin. The lowest resistance rates were observed for meropenem (4.88%), amikacin (12.20%), and tobramycin (12.2%). All isolates were susceptible to clove oil with an equivalent MIC and MBC from 3.26 to 6.53 mg/mL. Eugenol was the major component of the oil. Clove EO was effective against MDR strains of P. aeruginosa, indicating an alternative for developing an efficient and low-cost antimicrobial agent to treat canine otitis.