Antimicrobial Activity Of Cinnamaldehyde Research Articles

Antimicrobial activity of cinnamaldehyde against multidrug-resistant Klebsiella pneumoniae: an in vitro and in vivo study.

The emergence and spread of multidrug-resistant (MDR) Klebsiella pneumoniae strains have increased worldwide, posing a significant health threat by limiting the therapeutic options. This study aimed to investigate the antimicrobial potential of cinnamaldehyde against MDR-K. pneumoniae strains in vitro and in vivo assays. The presence of resistant genes in MDR- K. pneumoniae strains were evaluated by Polymerase Chain Reaction (PCR) and DNA sequencing. Carbapenem-resistant K. pneumoniae strains show the blaKPC-2 gene, while polymyxin-resistant K. pneumoniae presented blaKPC-2 and alterations in the mgrB gene. Cinnamaldehyde exhibited an inhibitory effect against all MDR- K. pneumoniae evaluated. An infected mice model was used to determine the in vivo effects against two K. pneumoniae strains, one carbapenem-resistant and another polymyxin-resistant. After 24h of cinnamaldehyde treatment, the bacterial load in blood and peritoneal fluids decreased. Cinnamaldehyde showed potential effectiveness as an antibacterial agent by inhibiting the growth of MDR-K. pneumoniae strains.

Antimicrobial Activity of Cinnamaldehyde, Carvacrol, and Lauric Arginate against Salmonella Tennessee in a Glycerol-Sucrose Model and Peanut Paste at Different Fat Concentrations

The objective of this study was to investigate the antimicrobial activities of carvacrol, cinnamaldehyde, and lauric arginate (LAE) against Salmonella in a low water activity (aw ) glycerol-sucrose model and in peanut paste with different fat concentrations. Salmonella Tennessee was inoculated into the model and the low fat (<5%) and high fat (50%) peanut paste adjusted to aw 1.0, 0.7, 0.5, and 0.3 and with or without cinnamaldehyde, carvacrol, or LAE. The survival of the bacterium over 3 or 5 days at 25°C was evaluated. Reduced aw alone decreased the viable population over time, with the highest reduction at the lowest aw. In the glycerol-sucrose model, all antimicrobial agents significantly reduced the population over time (P < 0.05) compared with the controls. LAE was more lethal than the essential oil components, reducing the population to undetectable levels by day 2 for all aw. Cinnamaldehyde was more effective than carvacrol at aw 0.5 and 0.3 (2.7- to 2.9-log versus 0.39- to 1.97-log reductions on day 3). In low-fat peanut paste, none of the antimicrobial agents inhibited growth of the pathogen at aw 1.0. However, inactivation was enhanced at reduced aw. Cinnamaldehyde and LAE both reduced the pathogen population to undetectable levels on day 5 at the highest concentration tested (ca. 10 times higher than that in the glycerol-sucrose model). Inactivation efficacy of all antimicrobial agents was greatly decreased but not eliminated in 50% fat peanut paste. Results suggest that the test antimicrobial agents were effective under low aw conditions, but significantly higher concentrations are needed for potential food applications, and fat concentration can negatively impact the efficacy of these antimicrobial agents.

Antimicrobial activity of cinnamaldehyde, vanillin and &lt;i&gt;Kigelia Africana&lt;/i&gt; fruit extracts against fish-associated &lt;i&gt;Chryseobacterium&lt;/i&gt; and &lt;i&gt;Myroides&lt;/i&gt; spp. isolates

Antimicrobial activity of cinnamaldehyde, vanillin and &lt;i&gt;Kigelia Africana&lt;/i&gt; fruit extracts against fish-associated &lt;i&gt;Chryseobacterium&lt;/i&gt; and &lt;i&gt;Myroides&lt;/i&gt; spp. isolates

Antimicrobial activity of cinnamaldehyde, vanillin and &lt;i&gt;Kigelia Africana&lt;/i&gt; fruit extracts against fish-associated &lt;i&gt;Chryseobacterium&lt;/i&gt; and &lt;i&gt;Myroides&lt;/i&gt; spp. isolates

Background: Members of the family Flavobacteriaceae exhibit intrinsic multi-drug resistance, which hampers their effective eradication. Phytochemicals are being explored as alternatives to the use of antimicrobial agents in aquaculture since they have growth-promoting, immunestimulating, and antimicrobial properties.Materials and Methods: The susceptibility of 36 Chryseobacterium and seven Myroides spp. isolates from salmon, tilapia and trout as well as 19 selected Flavobacteriaceae type strains to cinnamaldehyde, vanillin and four crude Kigelia africana extracts (ethyl acetate, dichloromethane, methanol and hexane), was assessed using disc diffusion assays and compared to standard antimicrobial agents, ampicillin and tetracycline using activity indices.Results: Cinnamaldehyde (≥250 μg/ml) was the most effective (77. 8 – 100% susceptibility) while vanillin was the least effective with inhibitory activity only at 1000 μg/ml. The K. africana hexane extract (4 mg/ml) was the most effective, with only 11.3% of isolates displaying resistance, while 94.4% of isolates demonstrated resistance to ampicillin and 38.9% susceptibility to tetracycline. K. africana extract inhibitory efficacy decreased in the following order: hexane &gt; ethyl acetate &gt; dichloromethane &gt; methanol. Cinnamaldehyde and K. africana EX 4 activity indices ≥ 1 were obtained for 83.3 - 97.2% and 25% of Chryseobacterium spp. isolates, respectively, relative to tetracycline.Conclusions: Cinnamaldehyde and K. africana fruit hexane extracts are promising candidates to be tested for their efficacy in the treatment of Chryseobacterium/Myroides-associated fish infections. These phytochemicals might serve as environmentally-friendly, cost-effective alternatives to the use of antimicrobial agents in aquaculture farms, with a lesser chance of resistance development.Keywords: phytotherapy; cinnamaldehyde; vanillin; Kigelia; Chryseobacterium; Myroides

Inhibitory effect of essential oils on Aspergillus ochraceus growth and ochratoxin A production.

Ochratoxin A (OTA) is a mycotoxin which is a common contaminant in grains during storage. Aspergillus ochraceus is the most common producer of OTA. Essential oils play a crucial role as a biocontrol in the reduction of fungal contamination. Essential oils namely natural cinnamaldehyde, cinnamon oil, synthetic cinnamaldehyde, Litsea citrate oil, citral, eugenol, peppermint, eucalyptus, anise and camphor oils, were tested for their efficacy against A. ochraceus growth and OTA production by fumigation and contact assays. Natural cinnamaldehyde proved to be the most effective against A. ochraceus when compared to other oils. Complete fungal growth inhibition was obtained at 150–250 µL/L with fumigation and 250–500 µL/L with contact assays for cinnamon oil, natural and synthetic cinnamaldehyde, L. citrate oil and citral. Essential oils had an impact on the ergosterol biosynthesis and OTA production. Complete inhibition of ergosterol biosynthesis was observed at ≥100 µg/mL of natural cinnamaldehyde and at 200 µg/mL of citral, but total inhibition was not observed at 200 µg/mL of eugenol. But, citral and eugenol could inhibit the OTA production at ≥75 µg/mL and ≥150 µg/mL respectively, while natural cinnamaldehyde couldn’t fully inhibit OTA production at ≤200 µg/mL. The inhibition of OTA by natural cinnamaldehyde is mainly due to the reduction in fungal biomass. However, citral and eugenol could significant inhibit the OTA biosynthetic pathway. Also, we observed that cinnamaldehyde was converted to cinnamic alcohol by A. ochraceus, suggesting that the antimicrobial activity of cinnamaldehyde was mainly attributed to its carbonyl aldehyde group. The study concludes that natural cinnamaldehyde, citral and eugenol could be potential biocontrol agents against OTA contamination in storage grains.

Examination of the genome-wide transcriptional response of Escherichia coli O157:H7 to cinnamaldehyde exposure.

Cinnamaldehyde is a natural antimicrobial that has been found to be effective against many food-borne pathogens, including Escherichia coli O157:H7. Although its antimicrobial effects have been well investigated, limited information is available on its effects at the molecular level. Sublethal treatment at 200 mg/liter cinnamaldehyde inhibited growth of E. coli O157:H7 at 37°C and for ≤2 h caused cell elongation, but from 2 to 4 h growth resumed and cells reverted to normal length. To understand this transient behavior, genome-wide transcriptional analysis of E. coli O157:H7 was performed at 2 and 4 h of exposure to cinnamaldehyde in conjunction with reverse-phase high-performance liquid chromatography (RP-HPLC) analysis for cinnamaldehyde and other cinnamic compounds. Drastically different gene expression profiles were obtained at 2 and 4 h. RP-HPLC analysis showed that cinnamaldehyde was structurally stable for at least 2 h. At 2 h of exposure, cinnamaldehyde induced expression of many oxidative stress-related genes and repressed expression of DNA, protein, O-antigen, and fimbrial synthetic genes. At 4 h, many cinnamaldehyde-induced repressive effects on E. coli O157:H7 gene expression were reversed, and cells became more motile and grew at a slightly higher rate. Data indicated that by 4 h, E. coli O157:H7 was able to convert cinnamaldehyde into the less toxic cinnamic alcohol using dehydrogenase/reductase enzymes (YqhD and DkgA). This is the first study to characterize the ability of E. coli O157:H7 to convert cinnamaldehyde into cinnamic alcohol which, in turn, showed that the antimicrobial activity of cinnamaldehyde is mainly attributable to its carbonyl aldehyde group.

Antibacterial Activity of Cinnamaldehyde and Sporan against Escherichia coli O157:H7 and Salmonella

The in vitro antimicrobial effect of cinnamaldehyde and Sporan in combination with acetic acid against Escherichia coli O157:H7 and Salmonella was investigated in Luria-Bertani broth (7 log cfu/mL) containing cinnamaldehyde or Sporan (800 and 1,000 ppm) alone or in combination with 200 ppm acetic acid, and incubated at 37C for up to 6 h. Surviving populations of test pathogens were determined by spiral plating on selective media. E. coli O157:H7 and Salmonella were undetectable after 1 h in the presence of 800 ppm cinnamaldehyde. A 1,000 ppm Sporan significantly reduced Salmonella and E. coli O157:H7 populations by 1.83 and 3.02 log cfu/mL within 2 and 4 h, respectively. Scanning and transmission electron microscopy of oil-treated bacterial cells revealed cell structural damage and leakage of cellular content. Cinnamaldehyde was highly effective against both E. coli O157:H7 and Salmonella whereas the effect of Sporan was dependent on its concentration, exposure time and pathogen. Practical Applications Consumers' preference for fewer chemicals in food has led to research on potential use of natural antimicrobials in food for controlling spoilage and pathogenic microorganisms. The antimicrobial effect of essential oils has been studied earlier. This is the first report on the antimicrobial activity of Sporan, and the combined effect of acetic acid. The results of the present study indicate that the antimicrobial activity of cinnamaldehyde and Sporan against enteric pathogens could be useful in food processing and preservation.

Antimicrobial Activity of Cinnamaldehyde and Eugenol and Their Activity after Incorporation into Cellulose‐based Packaging Films

Cinnamaldehyde and eugenol were investigated for their antimicrobial activity against 10 pathogenic and spoilage bacteria and three strains of yeast, using an agar‐well diffusion assay. The minimum inhibitory concentrations (MICs) of these compounds were determined using an agar dilution method. Finally, cinnamaldehyde‐incorporated and eugenol‐incorporated methyl cellulose films were prepared to obtain active antimicrobial packaging materials. These antimicrobial cellulose‐based packaging films were investigated for antimicrobial activity against target microorganisms using both an agar‐disc diffusion technique and a vapour diffusion technique. At a concentration of 50 µl/ml, cinnamaldehyde and eugenol revealed antimicrobial activity against all test strains. They showed zones of inhibition, ranging from 8.7 to 30.1 mm in diameter. Eugenol and cinnamaldehyde possessed ‘moderate−strong inhibitory’ and ‘strong−highly strong inhibitory’ characteristics, respectively. With MICs of 0.78−50 µl/ml, cinnamaldehyde and eugenol also inhibited the growth of all test microorganisms. Among the test microorganisms, Aeromonas hydrophila and Enterococcus faecalis were the most sensitive to cinnamaldehyde and eugenol. Cinnamaldehyde showed lower MICs against all test strains than those of eugenol. In an agar‐disc diffusion assay, cellulose‐based film containing cinnamaldehyde or eugenol totally failed to exhibit a clear inhibitory zone. However, it showed positive activity against all selected test strains in terms of size and enumeration of microbial colonies in a vapour diffusion assay. This study shows the potential use of cinnamaldehyde and eugenol for application in antimicrobial packaging film or coating. Copyright © 2011 John Wiley &amp; Sons, Ltd.