Cinnamon Leaf Oil Research Articles

In vivo and in silico Antifungal Activity of Cinnamon Leaf Oil and Lemongrass Oil containing Chitosan Microcapsules against Aspergillus flavus

In vivo and in silico Antifungal Activity of Cinnamon Leaf Oil and Lemongrass Oil containing Chitosan Microcapsules against Aspergillus flavus

Fatally impaired glucose digestion by propylene glycol in Aedes aegypti (Diptera: Culicidae) and co-formulation with terpenoids for enhancing attractive toxic sugar baits.

Propylene glycol (PG) demonstrates greater efficacy than other sugar polyols. However, the attributes it confers for toxicity and possible co-formulation with other ingredients are unknown. To evaluate this, α-glucosidase and glucose oxidase reactions were performed in Aedes aegypti (L.) (Diptera: Culicidae) to categorize if PG behaves similarly to prior studied sugar alcohols. A combination of no-choice and choice assays was used to determine effective ratios of PG and sucrose, competitiveness against a control of 10% sucrose, and whether mosquitoes recovered from PG consumption. The final trials included β-cyclodextrin encapsulated cinnamon leaf oil, clove stem oil, patchouli oil, garlic oil, cedarwood oil, and papaya seed oil formulated with 5% sucrose + 5% PG. PG functioned as a linear competitive inhibitor of α-glucosidase. The efficacy of PG was synergized by co-ingestion with equivalent ratios of sucrose. Unlike the high diuretic response to other sugar alcohols, PG resulted in diminished excretion regardless of being co-formulated with sucrose or terpenoids. PG is not especially competitive against unadulterated sugar meals but is likewise not clearly repellent. Although mosquitoes did not recover from ingestion of the glycol meals, there was no indication that mortality would continue to accumulate once the treatments were removed. Of the terpenoids tested, cinnamon and patchouli caused ~50% or less mortality; garlic, cedarwood, and clove caused 80-90% mortality; and papaya seed caused 100% mortality, exceeding all other test groups and the formulation blank. PG is a useful supporting ingredient in attractive toxic sugar bait formulations with flexibility in formulation.

Effect of various formulations of Piper aduncum botanical pesticide and concentration levels on fungal pathogen Fusarium oxysporum f.sp. cubense Vegetative Compatibility Group (VCG) 01213/16 Tropical strain 4 and VCG 01218 strain 1

Pathogen of Fusarium oxysporum f.sp. cubence (Foc) Vegetative Compatibility Group (VCG) 01213/16 (Tropical strain/TR4) and VCG 01218 (strain1) are the cause of wilt disease in banana. Plant-based pesticides are an alternative environmentally friendly substance that can control plant pathogens. This study aims to obtain a formulation of Piper aduncum oil with several essential oils to suppress the growth development of two Foc strains that cause wilt disease in banana plants. This study used a complete randomized design in factorial, where the first factor is the type of formulation: F1 = 25% P. aduncum leaf oil, F2 = P. aduncum leaf oil with lemongrass leaf oil (Cymbopogon flexiosus), F3 = P. aduncum oil with citronella leaves (Andropogon nardus), F4 = P. aduncum oil with Ceylon cinnamon leaf oil (Cinnamomum zeylanicum), F5 = P. aduncum oil with Padang cinnamon leaf oil (C. burmanii), F6 = P. aduncum oil with cloves leaf oil (Eugenia aromatica) F7=P. aduncum oil with wild ginger oil (Elettariopsis slahmong). The second factor is the concentration level: 1000, 2000, and 3000 ppm. The results showed that diameter of mycelium between Foc VCG01213/16 and VCG01218 did not differ significantly. However, there were significant differences in the botanical pesticide formulations used. P. aduncum oil formulation mixed with cloves leaf oil and ceylon cinnamon oil at a concentration level of 3000 ppm had better inhibition of colony diameter, namely for Foc VCG01213/16 (90.55% and 88.08%) and on Foc VCG 01218 (90.72% and 89.85%). Likewise, for the inhibition of colony biomass, the best formulation is the P. aduncum oil mixed with cloves leaf oil and with ceylon cinnamon oil, the concentration level at 3000 ppm for Foc VCG 01213/16 were 96.64 and 95.80%, respectively. In contrast, for Foc VCG 01218 were 96.00% for both.

Comprehensive Metabolite Profiling of Cinnamon (Cinnamomum zeylanicum) Leaf Oil Using LC-HR/MS, GC/MS, and GC-FID: Determination of Antiglaucoma, Antioxidant, Anticholinergic, and Antidiabetic Profiles.

In this study, for the first time, the antioxidant and antidiabetic properties of the essential oil from cinnamon (Cinnamomum zeylanicum) leaves were evaluated and investigated using various bioanalytical methods. In addition, the inhibitory effects of cinnamon oil on carbonic anhydrase II (hCA II), acetylcholinesterase (AChE), and α-amylase, which are associated with various metabolic diseases, were determined. Further, the phenolic contents of the essential oil were determined using LC-HRMS chromatography. Twenty-seven phenolic molecules were detected in cinnamon oil. Moreover, the amount and chemical profile of the essential oils present in cinnamon oil was determined using GC/MS and GC-FID analyses. (E)-cinnamaldehyde (72.98%), benzyl benzoate (4.01%), and trans-Cinnamyl acetate (3.36%) were the most common essential oils in cinnamon leaf oil. The radical scavenging activities of cinnamon oil were investigated using 1,1-diphenyl-2-picryl-hydrazil (DPPH•), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), and (ABTS•+) bioanalytical scavenging methods, which revealed its strong radical scavenging abilities (DPPH•, IC50: 4.78 μg/mL; and ABTS•+, IC50: 5.21 μg/mL). Similarly, the reducing capacities for iron (Fe3+), copper (Cu2+), and Fe3+-2,4,6-tri(2-pyridyl)-S-triazine (TPTZ) were investigated. Cinnamon oil also exhibited highly effective inhibition against hCA II (IC50: 243.24 μg/mL), AChE (IC50: 16.03 μg/mL), and α-amylase (IC50: 7.54μg/mL). This multidisciplinary study will be useful and pave the way for further studies for the determination of antioxidant properties and enzyme inhibition profiles of medically and industrially important plants and their oils.

Cinnamon Leaf and Clove Essential Oils Are Potent Inhibitors of Candida albicans Virulence Traits.

Plant-based essential oils are promising anti-virulence agents against the multidrug-resistant opportunistic pathogen Candida albicans. Gas chromatography–mass spectrometry of Cinnamomum zeylanicum (cinnamon) leaf and Eugenia caryophyllus (clove) flower bud essential oils revealed eugenol (73 and 75%, respectively) as their major component, with β-caryophyllene, eugenyl acetate, and α-humulene as common minor components. Cinnamon leaf and clove essential oils had minimum inhibitory concentrations of 600 and 500 µg/mL, respectively against the C. albicans RSY150 reference strain and 1000 and 750 µg/mL, respectively for the clinical reference strain ATCC 10231. The combined oils are additive (FICI = 0.72 ± 0.16) and synergistic (0.5 ± 0.0) against RSY150 and the clinical reference strain, respectively. Mycelial growth was inhibited by sublethal concentrations of either essential oil, which abolished colony growth. At half of the lowest combined lethal concentration for the two oils, the yeast-to-hyphal transition and mycelial growth was potently inhibited. Mutant strains als1Δ/Δ, als3Δ/Δ, hwp1Δ/HWP1+, and efg1Δ/Δ were sensitive to either or both oils, especially efg1Δ/Δ. In conclusion, oils of cinnamon leaf and clove and their combination significantly impact C. albicans virulence by inhibiting hyphal and mycelial growth.

Safety and efficacy of feed additives consisting of essential oils from the bark and the leaves of Cinnamomum verum J. Presl (cinnamon bark oil and cinnamon leaf oil) for use in all animal species (FEFANA asbl).

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of essential oils from the bark and the leaves of Cinnamomum verum J. Presl (cinnamon bark oil and cinnamon leaf oil), when used as sensory additives (flavourings) in feed and water for drinking for all animal species. Owing to the presence of styrene in the essential oils under assessment, the FEEDAP Panel is not in the position to conclude on the safety for long‐living animals and animals for reproduction. For ‘short‐living’ animals, the FEEDAP Panel concluded that cinnamon bark oil and cinnamon leaf oil are considered as safe up to the maximum proposed use levels in complete feed. For ‘short‐living’ animals, the Panel considered the use of cinnamon bark oil in water for drinking as safe provided that the total daily intake of the additive does not exceed the daily amount that is considered safe when consumed via feed. For cinnamon leaf oil, the proposed use level in water for drinking of 3 mg/L is considered as safe for ‘short‐living’ animals. No concerns for consumers were identified following the use of the additives at the use level considered safe in feed for the target species. Based on the presence of safrole ≥0.1%, cinnamon leaf oil and bark oil are classified as carcinogen (category 1B) and handled accordingly. The use of the additives under the proposed conditions in animal feed was not expected to pose a risk for the environment. Since C. verum and its preparations are recognised to flavour food and its function in feed would be essentially the same, no further demonstration of efficacy is considered necessary for cinnamon essential oils.

The effect of various essential oil and solvent additives on the botanical pesticide of Piper Aduncum essential oil on formulation antifungal activity

This study aims to obtain a formulation of the botanical pesticide P aduncum with additives and the right type of solvent. The research was arranged in a completely randomized design in factorial, the first factor being essential oil additives; citronellagrass oils (Andropogon nardus), lemongrass oils (Cimbopogon flexiosus), Ceylon cinnamon leaf oils (Cinnamomum zeylanicum), Padang cinnamon leaf oils (Cinnamomum burmanii), clove leaf oils (Eugenia aromatica) and wild ginger leaf oils (Elettariopsis slahmong), both types of solvent (ethanol, methanol and turpentine). The experiment was carried out at the Laing Solok IPPTP parasitology laboratory. The results showed that all additive materials had a positive effect in increasing the antifungal activity of the botanical pesticide P aduncum essential oil with different effectiveness against the test fungi. Citronella oil showed the highest antifungal effectiveness compared to other additives, especially against S. rolfsii and Pestalotia sp, with diameter and biomass inhibition of fungal colonies tested S rolfsii 92.15% and 92.70%, Pestalotia sp 84.82% and 86,34% and F. oxysporum 43.87 and 47.17%. All solvents can be used for the formulation of the botanical pesticide P aduncum, ethanol solvent is better than methanol and turpentine with the highest inhibition capacity of the diameter and biomass of the fungus colonies tested S rolfsii 91.28% and 92.05%, Pestalotia sp 83.56% and 86.02% and for F. oxysporum 40.31 and 48.36%, respectively.

Studies in instant water disinfection using natural oils

The present research reveals an instant and simple process for drinking water treatment by employing specific natural oils having antimicrobial properties to ensure complete elimination of harmful bacteria. The disinfection was studied for two different model bacteria, Gram-negative E. coli and Gram-positive, S. aureus. Seven natural oils, ajwain, thyme, oregano, peppermint, harsingar, cinnamon leaf and black pepper oil were evaluated and were found to yield 100% water disinfection within 1 min except for harsingar and black pepper oil. The process was also effective for the instant and 100% disinfection of real well water. The methodology for altering zeta potential, to an extent of 130%, for instant disinfection in drinking water treatment helps in selecting natural oils. Molecular docking studies indicated natural oils action as potential inhibitors of bacterial DNA gyrase. The studies indicate one of the lowest operating costs comparable to conventional chlorination. The simple methodology not requiring complex equipment has the potential to provide many options for implementations- from portability, household application to large scale water treatment plants.

BIOACTIVITY OF CINNAMON ESSENTIAL OIL

The interest in using antifungal instead of chemical preservatives in fruits and food products has been increasing in recent years. Regarding essential oils natural and liquid secondary plant metabolites are gaining importance of their use in the protection of foods. Since, they are safe and healthy. Cinnamon bark and leaf oils are selected essential oil. The antifungal activity of essential oil are mostly depend on its chemical constituents present in it which does not allowed the fungal hyphae and mycelium to grow in certain time of period. These oils are mainly used in pharmaceutical in order to preserve certain living entities. The phytochemicals present in this plant are mostly used for antifungal, antibacterial, antihistaminic, antipyretic etc. A review provides an overview of the current literature on cinnamon essential oils mainly antifungal activity, antibacterial activity, antioxidant activity, anti-mycotoxigenic activity.

Functional characterization of an olfactory receptor in the Oriental fruit fly, Bactrocera dorsalis, that responds to eugenol and isoeugenol.

Most insects utilize a diverse array of olfactory cues for host finding and reproduction behaviors. Males of several Dacini fruit fly species (Tephritidae) are selectively attracted to certain phytochemicals to acquire sex pheromone precursors. Despite the importance of olfaction, only a limited number of olfactory receptors (ORs) in Dacini fruit flies have been characterized. In this study, I focused on the OR94b-2 subfamily, because a clade consisting of these homologs was distinctly localized from other OR clades in a constructed phylogenetic tree. To deorphanize the ORs, I used plant essential oils to screen ligands. Using heterologous expression in Xenopus oocytes, I analyzed the functional properties of BdorOR94b-2 and ZcucOR94b-2 from the Oriental fruit fly, Bactrocera dorsalis, and the melon fruit fly, Zeugodacus cucurbitae, respectively. I found that cinnamon leaf oil evoked responses in oocytes expressing BdorOR94b-2 and the corresponding co-receptor BdorORCO. Gas chromatography-mass spectrometry analysis indicated that eugenol is a major component of cinnamon leaf oil. In accordance with the response to cinnamon leaf oil containing eugenol, BdorOR94b-2/BdorORCO revealed a weak but significant response to eugenol. BdorOR94b-2/BdorORCO also responded to isoeugenol, but not to other related aromatic semiochemicals such as known male-specific attractants and sex pheromones. In contrast, ZcucOR94b-2/ZcucORCO did not respond to any of the phenolic compounds tested, including eugenol analogs. Therefore, BdorOR94b-2/BdorORCO is narrowly tuned to eugenol analogs, whereas ZcucOR94b-2/ZcucORCO likely binds to other compound(s).

Efficacy of true cinnamon (Cinnamomum verum) leaf essential oil as a therapeutic alternative for Candida biofilm infections.

Objective(s):The essential oil (EO) extracted from Cinnamomum verum leaves has been used as an antimicrobial agent for centuries. But its antifungal and antibiofilm efficacy is still not clearly studied. The objective of this research was to evaluate the in vitro antifungal and antibiofilm efficacy of C. verum leaf EO against C. albicans, C. tropicalis, and C. dubliniensis and the toxicity of EO using an in vitro model.Materials and Methods:The effect of EO vapor was evaluated using a microatmosphere technique. CLSI microdilution assay was employed in determining the Minimum Inhibitory (MIC) and Fungicidal Concentrations (MFC). Killing time was determined using a standard protocol. The effect of EO on established biofilms was quantified and visualized using XTT and Scanning Electron Microscopy (SEM), respectively. Post-exposure intracellular changes were visualized using Transmission Electron Microscopy (TEM). The toxicological assessment was carried out with the Human Keratinocyte cell line. The chemical composition of EO was evaluated using Gas Chromatography-Mass Spectrometry (GC-MS).Results:All test strains were susceptible to cinnamon oil vapor. EO exhibited MIC value 1.0 mg/ml and MFC value 2.0 mg/ml against test strains. The killing time of cinnamon oil was 6 hr. Minimum Biofilm Inhibitory Concentration (MBIC50) for established biofilms was <0.2 mg/ml for all test strains. SEM images exhibited cell wall damages, cellular shrinkages, and decreased hyphal formation of Candida. TEM indicated intracellular vacuolation, granulation, and cell wall damages. Cinnamon leaf oil caused no inhibition of HaCaT cells at any concentration tested. Eugenol was the abundant compound in cinnamon oil.Conclusion:C. verum EO is a potential alternative anti-Candida agent with minimal toxicity on the human host.

Eugenol-Containing Essential Oils Loaded onto Chitosan/Polyvinyl Alcohol Blended Films and Their Ability to Eradicate Staphylococcus aureus or Pseudomonas aeruginosa from Infected Microenvironments.

Chronic wounds (CW) create numerous entryways for pathogen invasion and prosperity, further damaging host tissue and hindering its remodeling and repair. Essential oils (EOs) exert quick and efficient antimicrobial (AM) action, unlikely to induce bacterial resistance. Cinnamon leaf and clove oils (CLO and CO) display strong AM activity, namely against Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan (CS) is a natural and biodegradable cationic polysaccharide, also widely known for its AM features. CS and poly (vinyl alcohol) (PVA) films were prepared (ratio 30/70 w/w; 9 wt%) by the solvent casting and phase inversion method. The film’s thermal stability and chemical composition data reinforced polymer blending and EO entrapment. Films were supplemented with 1 and 10 wt% of EO in relation to total polymeric mass. The film thickness and degree of swelling (DS) tended to increase with EO content, particularly with 10 wt % CLO (* p < 0.05). UV-visible absorbance scans in the 250–320 cm−1 region confirmed the successful uptake of CLO and CO into CS/PVA films, particularly with films loaded with 10 wt% EO that contained 5.30/5.32 times more CLO/CO than films supplemented with 1 wt% EO. AM testing revealed that CS films alone were effective against both bacteria and capable of eradicating all P. aeruginosa within the hour (*** p < 0.001). Still, loaded CS/PVA films showed significantly improved AM traits in relation to unloaded films within 2 h of contact. This study is a first proof of concept that CLO and CO can be dispersed into CS/PVA films and show bactericidal effects, particularly against S. aureus, this way paving the way for efficient CW therapeutics.

Effect of spraying of essential oils and passive modified atmosphere packaging on selected postharvest quality parameters and stem-end rot development in &lt;em&gt;Mangifera indica&lt;em&gt; (cultivar &lt;em&gt;Karthakolomban&lt;/em&gt;)

Mangifera indica L. (cultivar Karthakolomban) is more prone to stem-end rot (SER) disease that causes substantial postharvest losses in quality as well as quantity. The objective of this study was to use aqueous emulsions of basil (1.6 μL/mL), clove (2.0 μL/mL), cinnamon leaf (2.0 μL/mL) and cinnamon bark (1.6 μL/mL) oils as sprays with passive modified atmosphere packaging (MAP) in low density polyethylene (LDPE) bags as a bio-safe strategy to control SER of ‘Karthakolomban’ mango stored at 12 – 14°C and 85 – 90% of relative humidity. Distilled water and 0.1% (w/v) carbendazim 50WP treatments were used as negative and positive controls respectively. In-package respiratory gases were measured during storage for 8 days. Pathological, physicochemical, sensory properties and peel color of mango were assessed after ripening fruits at the end of the storage period. All essential oil treatments combined with passive MAP significantly reduced SER severity of mango more than 93% when compared to the negative control without adversely affecting peel colour and some physicochemical properties like total soluble solids and firmness. Mango fruits treated with basil, clove and cinnamon leaf oils obtained a higher preference by the sensory panel than other treatments. In-package O2 concentration was at 3.8 – 5.8%, while CO2 was at 4.3 – 5.0% at the end of the 8-day storage period. Respiratory gas levels attained a steady state equilibrium which resulted in extending the shelf life. Further, T1, T2 and T3 treatments can be commercialized as eco-friendly treatment strategies to be used during transportation and storage of mango in local trade within one week and for exportation via air cargo that takes approximately 2 – 3 days.

In vitro antifungal efficacy of selected essential oils in controlling fungi associated with the stem-end rot disease of mango (cv. Karutha Colomban) fruits and characterisation of antifungal components

Karutha Colomban is one of the most delightful mango varieties popular among Sri Lankan consumers. A signifi cant postharvest loss of mango takes place every season due to diseases including stem-end rot (SER), which is caused by a group of endophytic fungal pathogens. In this research, in vitro antifungal efficacy of different concentrations of essential oils of basil, clove, and cinnamon were evaluated for their ability to control SER causing fungal pathogens of mango (cv. Karutha Colomban) as bio-safe alternatives to conventional fungicides by conducting liquid and disc volatilisation bioassays. Major bioactive compounds of the selected essential oils were identified by gas chromatography-mass spectroscopy (GC-MS). Basil and cinnamon bark oils (0.20–0.30 μL/mL) in liquid bioassay showed high efficacy against Lasiodiplodia theobromae, while basil and cinnamon leaf oils (0.40–0.60 μL/mL) successfully inhibited Pestalotiopsis sp. Cinnamon bark oil (0.60 μL/mL) was identified as the most effective oil against Phomopsis sp. According to disc volatilisation bioassay, vapour of cinnamon oils (0.20–0.40 μL/mL) were the most effective in controlling Lasiodiplodia theobromae. Pestalotiopsis sp. was efficiently controlled by clove and cinnamon bark oil (0.20–0.60 μL/mL) vapour. In vapour phase, clove and cinnamon oils (0.40 μL/mL) were the most effective against Phomopsis sp. According to GC-MS characterisation, methyl chavicol was the most abundant antifungal component in basil oil while it was (E)-cinnamaldehyde in cinnamon bark oil. Moreover, eugenol displayed the highest abundance in clove and cinnamon leaf oils. Based on in vitro studies, it could be concluded that cinnamon bark oil in liquid and vapour phases demonstrated a higher antifungal efficacy among the tested essential oils in controlling fungal pathogens causing SER of mango.

In vitro antifungal activity of Cinnamomum zeylanicum bark and leaf essential oils against Candida albicans and Candida auris

Candida infections are a significant source of patient morbidity and mortality. Candida albicans is the most common pathogen causing Candida infections. Candida auris is a newly described pathogen that is associated with multi-drug-resistant candidiasis and candidaemia in humans. The antifungal effects of various essential oils and plant compounds have been demonstrated against human pathogenic fungi. In this study, the effect of cinnamon leaf and bark essential oils (CEOs) was determined against both C. albicans and C. auris. The disc diffusion (direct and vapour) and broth microdilution method was used to determine antifungal activity of the EOs against selected strains (C. albicans ATCC 10231, C. albicans ATCC 2091 and C. auris NCPF 8971) whilst the mode of action and haemolysin activity of the CEOs were determined using electron microscopy and light microscopy. Direct and vapour diffusion assays showed greater inhibitory activity of bark CEO in comparison with leaf CEO. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of bark CEO for all tested strains was below 0.03% (v/v), which was lower than the MICs of the leaf CEO (0.06–0.13%, v/v) dependent on the strain and the MFCs at 0.25% (v/v). In the morphological interference assays, damage to the cell membrane was observed and both CEOs inhibited hyphae formation. The haemolysin production assay showed that CEOs can reduce the haemolytic activity in the tested C. albicans and C. auris strains. At low concentrations, CEOs have potent antifungal and antihaemolytic activities in vitro against C. albicans and C. auris.Key points• Essential oils from Cinnamomum zeylanicum Blume bark and leaf (CBEO and CLEO) demonstrated fungicidal properties at very low concentrations.• The antifungal activity of CBEO was greater than that of CLEO consistent with other recent published literature.• The mode of action of CBEO and CLEO was damage to the membrane of C. albicans and C. auris.• Both CBEO and CLEO inhibited the formation of hyphae and reduced haemolysin production in C. albicans and C. auris.Graphical abstract

Physical, Thermal, and Antibacterial Effects of Active Essential Oils with Potential for Biomedical Applications Loaded onto Cellulose Acetate/Polycaprolactone Wet-Spun Microfibers.

New approaches to deal with the growing concern associated with antibiotic-resistant bacteria are emerging daily. Essential oils (EOs) are natural antimicrobial substances with great potential to mitigate this situation. However, their volatile nature, in their liquid-free form, has restricted their generalized application in biomedicine. Here, we propose the use of cellulose acetate (CA)/polycaprolactone (PCL) wet-spun fibers as potential delivery platforms of selected EOs to fight infections caused by Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Twenty EOs were selected and screened for their minimal inhibitory concentration (MIC), using the antibiotic ampicillin as positive control. The cinnamon leaf oil (CLO), cajeput oil (CJO), and the clove oil (CO) were the most effective EOs, against the Gram-positive (MIC < 22.38 mg/mL) and the Gram-negative (MIC < 11.19 mg/mL) bacteria. Uniform microfibers were successfully wet-spun from CA/PCL with an averaged diameter of 53.9 ± 4.5 µm, and then modified by immersion with CLO, CJO and CO at 2 × MIC value. EOs incorporation was confirmed by UV-visible spectroscopy, Fourier-transformed infrared spectroscopy, and thermal gravimetric analysis. However, while microfibers contained ampicillin at MIC (control) after the 72 h modification, the CLO, CO and CJO-loaded fibers registered ≈ 14%, 66%, and 76% of their MIC value, respectively. Data showed that even at small amounts the EO-modified microfibers were effective against the tested bacteria, both by killing bacteria more quickly or by disrupting more easily their cytoplasmic membrane than ampicillin. Considering the amount immobilized, CLO-modified fibers were deemed the most effective from the EOs group. These results indicate that CA/PCL microfibers loaded with EOs can be easily produced with increased antibacterial action, envisioning their use as scaffolding materials for the treatment of infections.

Comparative study of the antioxidant activity of forty-five commonly used essential oils and their potential active components

This study was to examine the in vitro antioxidant activities of forty-five commonly used essential oils and their major components. The oils and major components were subjected to screening for their possible antioxidant activity by measuring the ABTS+. radical scavenging ability, reducing power and metal chelating activity. The ABTS+. radical scavenging ability and reducing power of cinnamon leaf and clove bud essential oils are the best two among these essential oils. At the concentration of 1 mg/mL, cinnamon leaf (96.45 ± 0.01%) and clove bud (96.33 ± 0.01%) essential oils showed the strongest ABTS+. radical scavenging ability. The EC 50 values of cinnamon leaf and clove bud essential oils are 12 μg/mL and 10 μg/mL, respectively. At the concentration of 10 mg/mL, cinnamon leaf and clove bud essential oils showed reducing power of 119.42 ± 0.68% and 112.92 ± 0.87% relative to butylated hydroxyanisole (BHA), respectively. Eugenol is the main component of cinnamon leaf and clove bud essential oils that contributes significantly to their ABTS+. radical scavenging activity and reducing power. In the metal chelating activity test system, basil essential oil was determined to be 57.48 ± 0.25% and its EC50 value is 984 μg/mL. Methyl chavicol is the major component of the basil essential oil that attributes greatly to its metal chelating activity. The higher phenolic content may explain the higher ABTS +. radical scavenging and reducing power activity of the forty-five kinds of commonly used essential oils. High electron density of the oxygen atom and low steric hindrance of the plane molecule of the methyl chavicol are the two possibilities that account for its higher metal chelating ability.

Maturity dependence of quality, quantity and chemical constituents of bark and leaf oil of Ceylon Cinnamon (&lt;em&gt;Cinnamomum zeylanicum&lt;/em&gt; Blume)

The maturity dependence of quality and quantity of bark and leaf oils of Ceylon Cinnamon were studied. Both genetic factors and ecological factors were maintained constant using two accessions of Ceylon Cinnamon, Sri Gamunu and Sri Vijaya, vegetatively cultivated at a field in the same agro-ecological zone, IL1a (601.7820N’; 80033.4990’E; 22.3 amsl.). Three maturity stages of plants, more than 5 years, between 2-2.5 years, and between 1.5-2 years, were used. Morphological analysis in two varieties showed that stick weight, bark dry weight, and leaf dry weight per stick were not significantly different in two varieties at the significance level α = 0.05. When compared the oil contents, Sri Gamunu had a higher oil yield than Sri Vijaya and both showed significantly higher yield at maturity stage of 2-2.5 years which was about the customarily identified maturity for harvesting (~2 years). In Sri Gamunu, about 78 % of bark oil consists of cinnamaldehyde and cinnamyl acetate while those in Sri Vijaya accounts only about 63% with higher content of eugenol and benzyl benzoate. In contrast, eugenol was the major component in leaf oil of cinnamon, which accounts for about 80 % and 87% in Sri Gamunu and Sri Vijaya, respectively. The study revealed that the best maturity stage to harvest both varieties of cinnamon is 2-2.5 years of maturity for maximum quality and quantity of cinnamon bark oil. Keywords: cinnamon, cinnamon bark oil, cinnamon leaf oil, cinnamon maturity

Activity of Specialized Biomolecules against Gram-Positive and Gram-Negative Bacteria.

The increased resistance of bacteria against conventional pharmaceutical solutions, the antibiotics, has raised serious health concerns. This has stimulated interest in the development of bio-based therapeutics with limited resistance, namely, essential oils (EOs) or antimicrobial peptides (AMPs). This study envisaged the evaluation of the antimicrobial efficacy of selected biomolecules, namely LL37, pexiganan, tea tree oil (TTO), cinnamon leaf oil (CLO) and niaouli oil (NO), against four bacteria commonly associated to nosocomial infections: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. The antibiotic vancomycin and silver nanoparticles (AgNPs) were used as control compounds for comparison purposes. The biomolecules were initially screened for their antibacterial efficacy using the agar-diffusion test, followed by the determination of minimal inhibitory concentrations (MICs), kill-time kinetics and the evaluation of the cell morphology upon 24 h exposure. All agents were effective against the selected bacteria. Interestingly, the AgNPs required a higher concentration (4000–1250 μg/mL) to induce the same effects as the AMPs (500–7.8 μg/mL) or EOs (365.2–19.7 μg/mL). Pexiganan and CLO were the most effective biomolecules, requiring lower concentrations to kill both Gram-positive and Gram-negative bacteria (62.5–7.8 μg/mL and 39.3–19.7 μg/mL, respectively), within a short period of time (averaging 2 h 15 min for all bacteria). Most biomolecules apparently disrupted the bacteria membrane stability due to the observed cell morphology deformation and by effecting on the intracellular space. AMPs were observed to induce morphological deformations and cellular content release, while EOs were seen to split and completely envelope bacteria. Data unraveled more of the potential of these new biomolecules as replacements for the conventional antibiotics and allowed us to take a step forward in the understanding of their mechanisms of action against infection-related bacteria.

Pathogenicity of Stem-end Rot Associated Fungi Isolated from Karthakolomban Mango and Their Control by Spray and Fumigation Treatments with Selected Essential Oils

Purpose: Stem-end rot (SER) is a major disease of mango that causes serious postharvest losses. Application of fungicides is environmentally unsound and is being practiced currently in its control. This study was conducted to develop essential oil treatment systems as eco-friendly strategies to control SER of Karthakolomban mango and to determine the pathogenicity of several SER associated fungi.Research Method: Pathogenicity of four fungal isolates in SER was assessed by inoculating them on Karthakolomban mango fruits. Karthakolomban mango fruits were subjected to spray and fumigation treatments using four essential oils and their pathological, physicochemical and sensory properties were evaluated after a 8-day storage at 12 – 14 ºC.Findings: Lasiodiplodia theobromae, Pestalotiopsis sp., Phomopsis sp. and Xylaria feejeensis were the major SER pathogens of mango. X. feejeensis was identified as a SER pathogen for the first time in Sri Lanka. Spray and fumigation treatments conducted using basil, clove, cinnamon leaf and cinnamon bark oils effectively controlled SER of Karthakolomban mango stored at 12 – 14 ºC for 8 days. Mango sprayed with 1.6 µL/mL cinnamon bark oil has displayed no SER after induced ripening. None of the treatments caused drastic alterations in physicochemical and sensory properties of mango.Research Limitations: Storage period of mango was restricted to 8 days due to the initiation of natural ripening which was the major limitation to achieving a further enhanced shelf life.Originality/value: The treatment strategies developed by this research could be commercialized as bio-safe SER control strategies in reducing postharvest losses of mango in the local and international trade.