Project description:ObjectivesMethod-dependent comparison of antimicrobial agents' efficacy against oral pathogens.Materials and methodsSeveral sodium hypochlorite solutions (NaOCl)-Perisolv®, Carisolv® and Dakin's solution-were equated with chlorhexidine (CHX) and hydrogen peroxide (H2O2) against ten oral micro-organisms related to caries and periodontitis using different minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) techniques. Agents were adjusted to the final 70 mmol/L concentration of active chlorine molecule.ResultsApart from H2O2 and the amino acids of Perisolv®, all the agents revealed an antimicrobial effect. Agar diffusion test ranked CHX (p < 0.05) as the most effective against all ten specimens, followed by the NaOCl of Perisolv® and Dakin's solution. Correspondingly, in broth microdilution on agar, CHX was the most effective in eradicating micro-organisms at 0.03 mmol/L compared with 2.2 mmol/L of Dakin's solution. In contrast, the bactericidal concentration of Dakin's solution was the most effective at 0.2 mmol/L, (p < 0.001), followed by Perisolv® (2.14 mmol/L), CHX (2.38 mmol/L) and Carisolv® (3.33 mmol/L) after 5 and 10 min in broth dilution test. In live/dead analysis, 60-min exposure to a 2-fold concentration of agents resulted in two-log Aggregatibacter actinomycetemcomitans inhibition by CHX (35 mmol/L) whilst Streptococcus mutans was more susceptible, in 0.8 and 8.8 mmol/L, after 10 min to CHX and Dakin's respectively.ConclusionReplacement of CHX with tested hypochlorite agents showed evident potential and promoted rapid antimicrobial effect.Clinical relevanceEffective antimicrobial agents are crucial in controlling pathogen-induced oral infections increasing clinical possibilities to combat oral biofilms. Additionally, CHX substitution with hypochlorite agents could eliminate CHX's adverse effects.
Project description:The inhibitory potential by contact and vapor of basil, cinnamon, clove, peppermint, oregano, rosemary, common thyme, and red thyme essential oils (EOs) against 20 strains of Streptococcus suis was determined by the disk diffusion test. The broth microdilution method was used to determine the minimal inhibitory and minimal bactericidal concentration (MIC and MBC) of the four selected oils. Furthermore, the bactericidal power (ratio MBC/MIC) was calculated. The EOs with the major potential in the disk diffusion method were red thyme, common thyme, oregano, and cinnamon (∅ mean 16.5-34.2 mm), whereas cinnamon did not show vapor activity. In the microdilution test, all the EOs showed notable antimicrobial activity (MIC90 and MBC90 312.5-625 μg·ml-1 ) and a strong bactericidal power (ratio = 1). This is the first study that selects essential oils against S. suis. New studies about the possible synergic effect of EOs with antibiotics and about toxicity and efficacy in in vivo conditions are recommended.
Project description:Essential oils (EOs) and plant extracts have demonstrated inhibitory activity against a wide range of pathogenic bacteria. In this study, the chemical composition of manuka, kanuka, peppermint, thyme, lavender, and feijoa leaf and peel EOs and feijoa peel and leaf extracts were analyzed, and their antimicrobial activity against Escherichia coli, Salmonella enterica Typhimurium, Staphylococcus aureus, Bacillus cereus, and Listeria monocytogenes were determined. The results showed that the major compounds varied among different EOs and extracts, with menthol in peppermint EO, thymol and carvacrol in thyme EO, linalool in lavender EO, β-caryophyllene in feijoa EO, and flavones in feijoa extract being the most prevalent. The study found that while EOs/extracts had antimicrobial activity alone, no individual EO/extract was highly effective against all tested species. Therefore, their combinations were tested to identify those that could broaden the spectrum of activity and act synergistically. The checkerboard method was applied to assess the possible synergism between the paired combinations of EOs/extract. The peppermint/thyme, peppermint/lavender, and peppermint/feijoa peel extract combinations exhibited a synergistic effect against E. coli and L. monocytogenes, with the peppermint/thyme and peppermint/feijoa peel extract combinations being the most effective against all five pathogens. Time-to-kill kinetics assays demonstrated that peppermint/thyme and peppermint/feijoa peel extract combinations achieved complete eradication of E. coli within 10-30 min and L. monocytogenes within 4-6 h. This study provides a promising approach to developing a natural alternative for food preservation using synergistic combinations of EOs/extracts, which could potentially reduce the required dosage and broaden their application in food products as natural preservatives.
Project description:This study aimed to analyze the essential oils of the aerial parts (A) and flowers (F) of Rosa banksiae var. banksiae Ait. (RBW), Rosa polyantha Thunb. "orange fairy" (RPO) and Rosa polyantha Thunb. "white fairy" (RPW), family Rosaceae, and perform multivariate data analyses and antimicrobial activity evaluations. The essential oil analyses were performed by GC/FID and GC/MS. Principal component analysis (PCA), hierarchical cluster analysis (HCA), and clustered heat map were used for the multivariate analyses. The antimicrobial activity was evaluated by the well-diffusion method against four bacteria and four fungi. Two hundred fifty-three compounds were identified from the six oil samples. The major components in RBW-A, RPO-A, and RPW-A were n-undecane (14.40, 19.36, and 9.21%) n-dodecane (14.54, 22.13, and 8.39%), and yomogi alcohol (8.41, 10.53, and 6.28%), respectively, whereas RBW-F, RPO-F and RPW-F contained n-heptadecane (16.70%), n-undecane (7.98%), and β-phellandrene (22.78%), respectively. The tested essential oils showed moderate antifungal activity against Aspergillus fumigatus compared to amphotericin B. PCA and HCA revealed five main clusters. The six samples carried close chemical profiles and can be regarded as fruitful sources of safe antifungal agents.
Project description:Medicinal plants represent a great source of antimicrobial and phytochemical constituents which are increasingly used to treat microbial infections and other ailments such as tuberculosis, anemia, and trachoma. Despite the use of antibiotics, antimicrobial resistance continues to be a world issue, in as much as nutrition. This study investigated the presence of phytochemicals, proximate compositions, and antimicrobial activity of methanolic extract of Carapa procera bark. The bark of Carapa procera was collected, cleaned and air dried for 72 h. The powder obtained was treated with diethyl ether and soaked in methanol (99%) for 72 h to obtain crude extract. The extract was used to test for the presence of phytochemicals and antimicrobial activities. The raw bark was used for proximate analysis. The result showed presence of steroids, tannins and saponins, but no alkaloids present. The 100 mg/mL extract had the highest inhibition zone on all tested organisms from 24.00 ± 0.94 to 26.67 ± 1.18, and 50 mg/mL showed the least (16.67 ± 1.24) on Candida albicans. Staphylococcus aureus showed the lowest minimum inhibition concentration (MIC) of 3.12 mg/mL, whereas the Gram-negative bacteria exhibited variations in their sensitivity with E. coli having the highest MIC of 25 mg/mL. The extract had high MIC (6.25 mg/mL) on Candida albicans than clotrimazole (50 mg/mL). The proximate compositions of Carapa procera were moisture (6.07 ± 0.07%), ash (12.46 ± 0.46%), crude protein (9.54 ± 0.12%), crude fat (1.42 ± 0.06%) and carbohydrate (70.50 ± 0.35%). The energy value was 1413.17 kj. Thus, Carapa procera possesses both antimicrobial and nutritional potentials worth exploring and domesticating for sustainable management and conservation.
Project description:Chemical fingerprints of four different Satureja montana L. essential oils (SEOs) were assayed by an untargeted metabolomics approach based on Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) coupled with either electrospray ionization or atmospheric pressure chemical ionization ion sources. Analysis and relative quantification of the non-polar volatile fraction were conducted by gas chromatography (GC) coupled to MS. FT-ICR MS confirmed significant differences in the polar metabolite composition, while GC-MS analyses confirmed slight fluctuations in the relative amount of major terpenes and terpenoids, known to play a key role in antimicrobial mechanisms. Oil in eater (O/W) nanoemulsions (NEs) composed by SEOs and Tween 20 or Tween 80 were prepared and analyzed in terms of hydrodynamic diameter, ζ-potential and polydispersity index. The results confirm the formation of stable NEs homogeneous in size. Minimum inhibitory and minimum bactericidal concentrations of SEOs were determined towards Gram-positive (Listeria monocytogenes, Staphylococcus aureus, Staphylococcus haemolyticus) and Gram-negative clinical isolates (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens). Commercial SEO showed strongest antibacterial activity, while SEO 3 was found to be the most active among the lab made extractions. MIC and MBC values ranged from 0.39 to 6.25 mg·mL-1. Furthermore, a SEO structured in NEs formulation was able to preserve and improve antimicrobial activity.
Project description:Recently, the application of herbal medicine for the prevention and treatment of diseases has gained increasing attention. Essential oils (EOs) are generally known to exert various pharmacological effects, such as antiallergic, anticancer, anti-inflammatory, and immunomodulatory effects. Current literature involving in vitro and in vivo studies indicates the potential of various herbal essential oils as suitable immunomodulators for the alternative treatment of infectious or immune diseases. This review highlights the cellular effects induced by EOs, as well as the molecular impacts of EOs on cytokines, immunoglobulins, or regulatory pathways. The results reviewed in this article revealed a significant reduction in relevant proinflammatory cytokines, as well as induction of anti-inflammatory markers. Remarkably, very little clinical study data involving the immunomodulatory effects of EOs are available. Furthermore, several studies led to contradictory results, emphasizing the need for a multiapproach system to better characterize EOs. While immunomodulatory effects were reported, the toxic potential of EOs must be clearly considered in order to secure future applications.
Project description:Essential oils (EOs) isolated from different plant materials, namely Origanum majorana L., Satureja hortensis L., and Satureja montana L. (OMEO, SHEO, and SMEO, respectively), were used in fresh turkey sausage processing. The chemical composition and in vitro antimicrobial potential of selected EOs and their mixture were determined. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against foodborne pathogens (Escherichia coli, Salmonella Enteritidis, and Listeria monocytogenes) ranged in the interval of 0.44-7.1 µL/mL. Fresh turkey sausages were produced with EOs addition and marked as follows: TOMEO-0.150 µL/g OMEO; TSHEO-0.150 µL/g SHEO; TSMEO-0.150 µL/g SMEO; TEOM-0.050 µL/g OMEO, 0.050 µL/g SHEO and 0.050 µL/g SMEO, and control (C) (without EOs). Microbiological profile and biogenic amines content in fresh turkey sausages were recorded during storage. The selected EOs and their mixture efficiently reduced bacterial growth and biogenic amines formation and accumulation. The lowest Enterobacteriaceae count and total biogenic amine (BA) concentration were determined through treatment TSHEO. The results of this study show that selected EOs could be useful in fresh turkey sausage processing in order to improve safety and shelf-life.
Project description:The genus Callistemon comprises evergreen shrubs or small trees, widely cultivated as ornamentals and for essential oil production. Callistemon is well-recognized in folk medicine for its anti-cough, anti-bronchitis, and insecticidal activities. In the current study, we profiled the essential oil composition of the leaves of C. citrinus, C. rigidus and C. viminalis (Myrtaceae) collected during different seasons by GLC-MS coupled to multivariate data analysis. Antioxidant, anti-inflammatory and anti-proliferative activities of Callistemon essential oils were evaluated. A total of 29 compounds were tentatively identified. Oxygenated monoterpenes dominated in essential oils, where eucalyptol represented the major constituent in the three Callistemon species in all seasons. Multivariate data analysis including Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were applied to discriminate between different Callistemon species in each season and to investigate any correlation between the metabolic profile of each species within different seasons. As expected, PCA plot could discriminate the three Callistemon species in the four seasons. The dendrogram from HCA confirmed the results of PCA as it showed the same segregation pattern regarding the discrimination of different Callistemon species. C. viminalis showed more pronounced antioxidant activity than C. citrinus, exhibiting IC50 values of 1.40 mg/mL and 1.77 mg/mL, respectively. Meanwhile, C. rigidus showed very weak antioxidant activity. All oils showed membrane stabilization activity in hypotonic solution induced haemolysis assay, where C. viminalis showed potent membrane stabilizing activity exhibiting IC50 value of 25.6 μg/mL comparable to that of the standard drug, indomethacin (17.02 μg/mL). Nevertheless, Callistemon essential oils were not cytotoxic in HCT-116 and Hela human cancer cell lines.
Project description:Administration of essential oils as natural plant products with antimicrobial activity might be an alternative to antibiotic treatment of bovine respiratory disease. The aim of this study was to analyse the in vitro antimicrobial activity of 11 essential oils against Pasteurella multocida isolated from the respiratory tract of calves using microdilution with determination of minimum inhibitory and bactericidal concentration as well as agar disc diffusion. Additionally, antimicrobial activity against Mannheimia haemolytica and bacteria in the Mannheimia clade was assessed by agar disc diffusion. Seven essential oil mixtures were also tested against all bacterial isolates. P. multocida was strongly inhibited by cinnamon cassia and lemongrass oil followed by coriander, winter savory, thyme, clove, and peppermint oil in the microdilution assays. Eucalyptus, wintergreen, spruce, and star anise oil showed lower activity. Comparison of both methods revealed an underestimation of cinnamon cassia oil activity by agar disc diffusion and conflicting results for wintergreen oil in microdilution, which precipitated in broth. Cinnamon cassia, thyme, wintergreen, lemongrass, and winter savory oil all showed strong antimicrobial activity against M. haemolytica. Bacteria in the Mannheimia clade were mostly inhibited by cinnamon cassia and thyme oil. Pasteurella isolates were more susceptible to inhibition by essential oils than Mannheimia isolates. Essential oil mixtures did not show stronger antibacterial activity than single essential oils. In conclusion, cinnamon cassia and lemongrass as well as coriander, winter savory, and thyme oil are promising candidates for treatment of P. multocida-associated bovine respiratory infections.