Control of pathogenic bacterial biofilm associated with acne and the anti-inflammatory potential of an essential oil blend.

Acne is one of the most common skin conditions worldwide, with multifactorial origins it affects areas of the skin with hair follicles and sebaceous glands that become clogged. Bacterial incidence aggravates treatment due to resistance to antimicrobial agents and production of virulence factors such as biofilm formation. Based on these information, this study aims to conduct in vitro evaluations of the antibacterial activity of essential oils (EOs), alone and in combination, against Propionibacterium acnes, Staphylococcus aureus, and Staphylococcus epidermidis in planktonic and biofilm forms. This study also assessed the anti-inflammatory potential (TNF-α) and the effects of EOs on the viability of human keratinocytes (HaCaT), murine fibroblasts (3T3-L1), and bone marrow-derived macrophages (BMDMs). Of all EOs tested, 13 had active action against P. acnes, 9 against S. aureus, and 9 against S. epidermidis at concentrations of 0.125-2.0 mg/mL. Among the most active plant species, a blend of essential oil (BEOs) was selected, with Cymbopogon martini (Roxb.) Will. Watson, Eugenia uniflora L., and Varronia curassavica Jacq., the latter due to its anti-inflammatory action. This BEOs showed higher inhibition rates when compared to chloramphenicol against S. aureus and S. epidermidis, and higher eradication rates when compared to chloramphenicol for the three target species. The BEOs did not affect the cell viability of cell lines evaluated, and the levels of TNF-α decreased. According to these results, the BEOs evaluated showed potential for the development of an alternative natural formulation for the treatment of acne.

Synergism Between Essential Oils and Evaluation of Their Activities with a Focus on Malassezia furfur Control.

Seborrheic dermatitis is a chronic inflammatory disease caused by Malassezia yeast species that affects the regions of the body where the sebaceous glands are present. The combined use of different essential oils (EOs) can increase their spectrum of action. Thus, the present study aimed to evaluate the action of EOs alone and in combination with each other on M. furfur, in planktonic and biofilm form, and their anti-inflammatory and mutagenic potential, in addition to the effects on the viability of cells lines. Of the 40 evaluated EOs, 22 showed activity against M. furfur at 0.5 - 2.0 mg/mL concentrations. Among the most active species, a blend of essential oils (BEOs) composed of Cymbopogon martini (Roxb.) Will. Watson (MIC = 0.5 mg/mL) and Mentha × piperita L. (MIC = 1.0 mg/mL) was selected, which showed a synergistic effect against yeast when evaluated through the checkerboard assay. The fungicidal activity was maintained by the addition of anti-inflammatory oil from Varronia curassavica Jacq. to BEOs. The BEOs also showed activity in the inhibition of biofilm formation and in the eradication of the biofilm formed by M. furfur, being superior to the action of fluconazole. Furthermore, it did not show mutagenic potential and did not interfere with the cell viability of both evaluated cell lines (HaCaT and BMDMs). TNF-α levels were reduced only by C. martini; however, this property was maintained when evaluating BEOs. BEOs had no effect on IL-8 levels. Thus, the BEOs may be indicated for alternative treatments against seborrheic dermatitis.

Identification of Coumarins and Antimicrobial Potential of Ethanolic Extracts of Dipteryx odorata and Dipteryx punctata.

Dipteryx odorata and Dipteryx punctata are species native to the Amazonian, traded by extractivists to obtain coumarin. We aimed to analyze the presence of coumarin in the ethanolic extracts of leaves, branches and fruits of D. odorata and D. punctata and to evaluate the antimicrobial activity of these extracts against phytopathogenic fungi and bacteria of clinical interest. Chemical analyses were performed by thin layer chromatography (TLC) and by gas chromatography coupled to mass spectrometry (GC-MS). For the antifungal assays, the fungi used were Cercospora longissima, Colletotrichum gloeosporioides, two isolates of Fusarium spp. and Sclerotium rolfsii, and the antibacterial assay was performed using the minimum inhibitory concentration (MIC) test with Burkholderia cepacia, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus bacteria. In D. odorata seed extracts and in D. punctata husks, endocarps, and seeds, we identified 1,2-benzopyrone. D. odorata endocarp extracts and D. punctata seeds provided the greatest decrease in mycelial growth of the evaluated phytopathogens, showing promise as an alternative control. The husk and endocarp extracts of both species had a weak effect on E. coli. This research is the first to compare the different parts of species of the genus Dipteryx and to evaluate the use of husks and endocarps of D. punctata fruits to obtain coumarin. Chemical analyses used to quantify the compounds existing in the extracts, and tests with phytopathogens in vitro and in vivo are currently being carried out.

Effects of Artemisia annua alcohol extract on physiological and innate immunity of Nile tilapia (Oreochromis niloticus) to improve health status.

Plants are a potential source of active molecules and are environmentally safer and cheaper than synthetic antibiotics. Bioactive compounds of Artemisia annua have shown pharmacological activities and are used globally as a supplement. The present study tested whether dietary supplementation with alcohol extract of the plant A. annua (ae-Aa; patent BR10201902707) improves the health status of juvenile Nile tilapia and increases resistance to diseases when fish are challenged with the bacteria Aeromonas hydrophila. The experimental design was completely randomized with four experimental groups (0.0, 0.1, 0.25, and 0.5% ae-Aa in the diets) with five repetitions (12 fish per repetition/experimental unit). We assessed serum glucose and cortisol levels in plasma, leukocyte respiratory activity, total plasma protein, serum lysozyme levels, as well as the number of circulating red blood cells and fish leukocytes at the end of the 30 days of feeding (phase I) and 24h after exposure to bacteria (phase II). The levels of lipid peroxidation, catalase activity and glutathione S-transferase of fish were also analyzed. The supplementation of 0.5% of ae-Aa was sufficient to increase the respiratory burst of leukocyte and lysozyme activity, total plasma protein, blood thrombocytes, neutrophils and monocytes after bacterial challenge (P < 0.05), and minimized stress response with decreases in plasmatic glucose and cortisol, and reduction in lipid peroxidation levels (P < 0.05). Results of the present study suggest that ae-Aa as a dietary supplement has benefits, including supplementation with 0.5% A. annua extract for 30 days to minimize the stress response and modulate innate immunity in Nile tilapia, providing fish with greater resistance and disease protection.

Antimicrobial Activity of Schinopsis brasiliensis Engler Extract-Loaded Chitosan Microparticles in Oral Infectious Disease.

Enterococcus faecalis infections represent a health concern, mainly in oral diseases, in which treatments with chlorhexidine solution (0.2%) are often used; however, it presents high toxicity degree and several side effects. Based on this, the use of natural products as an alternative to treatment has been explored. Nonetheless, plant extracts have poor organoleptic characteristics that impair theirs in natura use. Therefore, this work aimed to evaluate the analytical profile, biological activity, and cytotoxicity in vitro of S. brasiliensis-loaded chitosan microparticles (CMSb) produced using different aspersion flow rates. The analytical fingerprint was obtained by FTIR and NIR spectra. Principal components analysis (PCA) was used to verify the similarity between the samples. The crystallinity degree was evaluated by X-ray diffraction (XRD). Phytochemical screening (PS) was performed to quantify phytocompounds. Antimicrobial activity was evaluated by minimum inhibitory concentration (MIC). Antibiofilm activity and bactericidal kinetics against E. faecalis (ATCC 29212 and MB 146-clinical isolated) were also assessed. The hemolytic potential was performed to evaluate the cytotoxicity. Data provided by FTIR, NIR, and PCA analyses revealed chemical similarity between all CMSb. Furthermore, the results from XRD analysis showed that the obtained CMSb present amorphous characteristic. Tannins and polyphenols were accurately quantified by the PS, but methodology limitations did not allow the flavonoid quantification. The low hemolytic potential assay indicates that all samples are safe. Antimicrobial assays revealed that CMSb were able to inhibit not only the E. faecalis ATCC growth but also the biofilm formation. Only one CMSb sample was able to inhibit the clinical strain. These results highlighted the CMSb antimicrobial potential and revealed this system as a promising product to treat infections caused by E. faecalis.

Quality assessment of sulfurous thermal waters in the city of Poços de caldas, Minas gerais, Brazil.

Currently, the quality of the water consumed by the population, and also the water used for both leisure and therapeutic bathing, are known. In the city of Poços de Caldas, Minas Gerais, Brazil, the population has two sources of sulfurous thermal water, with free access for various purposes, including drinking. Since 1882, the system has retained the same structural characteristics, and at this time, there appears to be a risk of anthropogenic contamination due to population increase near the springs. The aim of this study was to evaluate the water quality of the sulfurous hot springs distributed in Pedro Botelho fountain, located in Thermas Antônio Carlos, and Monkey fountain, located in Mario Mourao bathhouse, for microbiological and bacteriological components, physical and chemical composition, and radionuclides for a period of 12 months and to compare their quality with Brazilian water quality laws. The results showed that all the values are within the prescribed water quality parameters, except fluoride and sodium, whose levels are above those permitted by law. Excess fluoride in consumed water can cause dental fluorosis and skeletal fluorosis. As for sodium, which exceeded the permissible limits by 20 to 25 %, it can be detrimental to hypertensive individuals. An important fact to consider is that water from sulfurous hot springs cannot be consumed without medical supervision because its chemical characteristics may cause damage to health, and it should only be used as medicinal mineral water.

In vitro determination of the susceptibility of Malassezia furfur biofilm to different commercially used antimicrobials.

Malassezia furfur is a yeast known as the etiological agent of seborrheic dermatitis. We evaluated the action of five different antimicrobials (amphotericin B, chloramphenicol, ketoconazole, fluconazole, and nystatin) on inhibiting biofilm formation and removing biofilm already formed by M. furfur. The assays were carried out using the microdilution method, and scanning electron microscopy images were used to analyze the biofilm structure. According to the results obtained, the percentage of inhibition was higher for chloramphenicol, followed by ketoconazole, nystatin, and amphotericin B. Regarding the eradication of the biofilm formed, the highest percentage was chloramphenicol, followed by ketoconazole and nystatin. Amphotericin B did not affect biofilm eradication, whereas fluconazole did not cause significant changes inhibiting or removing M. furfur biofilm. Therefore, except for fluconazole, all evaluated antimicrobials had inhibiting effects on the biofilm of M. furfur, either in its formation and/or eradication. Although the results achieved with chloramphenicol have been highlighted, further in vitro and in vivo studies are still needed in order to include this antimicrobial in the therapy of seborrheic dermatitis due to its toxicity, especially to the bone marrow.

Limonene and its derived oligomer as bioactive additives in starch/coffee husks biocomposites for food packaging applications.

In this study, antioxidant, and antimicrobial starch-based biocomposite films reinforced with coffee husks (S/CH) were developed by incorporating either limonene (LM) (S/CH/LM) or its oligomer derivative, poly(limonene) (PLM) (S/CH/PLM), at different concentrations (5-10 % w/w of starch). Through a comprehensive assessment of film properties, morphology, and structure, a comparative analysis between the two additives was proposed. Scanning electron microscopy (SEM) revealed some defects throughout the polymer matrix after additive incorporation. The tensile strength (TS) and modulus of elasticity (ME) showed a decrease upon the inclusion of both LM and PLM, while the elongation at break (E) increased. Notably, PLM exhibited outstanding antioxidant capacity, enhancing the films by 108 % over control samples. Additionally, at just 5 % concentration, PLM effectively inhibited the growth of Escherichia coli ATCC 11775 (35.33 ± 2.52 mm) and demonstrated an impressive UV-Vis barrier, comparable to the highest amount of LM incorporated. Therefore, this research highlights the potential of coffee husk-reinforced starch biocomposites with limonene-derived additives as a promising solution for food packaging applications. The comparative analysis sheds light on the advantages of using the PLM in terms of antioxidant and antimicrobial properties, contributing to the advancement of active packaging technologies.

Impact of Microencapsulation on Ocimum gratissimum L. Essential Oil: Antimicrobial, Antioxidant Activities, and Chemical Composition.

Ocimum gratissimum (OG) is a species rich in essential oils (EO), which is known for its antimicrobial and antioxidant properties. This study aimed to encapsulate the essential oil of Ocimum gratissimum (OGE), determine its chemical composition, and evaluate its antioxidant and antimicrobial activities against six pathogenic bacteria, comparing it with the free essential oil (OGF). The EO was extracted by hydrodistillation using a Clevenger-type apparatus, and an oil-in-water emulsion was prepared using a combination of biopolymers: maltodextrin (MA), cashew gum (CG), and inulin (IN). The chemical profile was identified using gas chromatography-mass spectrometry (GC-MS). Antioxidant activity was assessed using the Oxygen Radical Absorbance Capacity with fluorescein (ORAC-FL) method, while the Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) were determined by the microdilution method. Microparticles were formed using the spray-drying method, achieving an encapsulation efficiency of 45.2%. The analysis identified eugenol as the main compound both before and after microencapsulation. The OGE microparticles demonstrated high inhibitory and bactericidal effects against S. aureus, S. choleraesuis, and E. coli, with MIC values of 500 µg·mL-1 and MBC values of 1000 µg·mL-1, as well as antioxidant activity of 1914.0 µmol-TE·g-1. Therefore, it can be inferred that the EO of OG maintained its antimicrobial and antioxidant effects even after microencapsulation by spray-drying, making it a promising natural ingredient.

Quaternization of cassava starch and determination of antimicrobial activity against bacteria and coronavirus.

This study describes the novel development of quaternized cassava starch (Q-CS) with antimicrobial and antiviral properties, particularly effective against the MHV-3 coronavirus. The preparation of Q-CS involved the reaction of cassava starch (CS) with glycidyltrimethylammonium chloride (GTMAC) in an alkaline solution. Q-CS physicochemical properties were determined by FTIR, NMR, elemental analysis, zeta potential, TGA, and moisture sorption. FTIR and NMR spectra confirmed the introduction of cationic groups in the CS structure. The elemental analysis revealed a degree of substitution (DS) of 0.552 of the cationic reagent on the hydroxyl groups of CS. Furthermore, Q-CS exhibited a positive zeta potential value (+28.6 ± 0.60 mV) attributed to the high positive charge density shown by the quaternary ammonium groups. Q-CS demonstrated lower thermal stability and higher moisture sorption compared to CS. The antimicrobial activity of Q-CS was confirmed against Escherichia coli (MIC = 0.156 mg mL-1) and Staphylococcus aureus (MIC = 0.312 mg mL-1), along with a remarkable ability to inactivate 99% of MHV-3 coronavirus after only 1 min of direct contact. Additionally, Q-CS showed high cell viability (close to 100%) and minimal cytotoxicity effects, guaranteeing its safe use. Therefore, these findings indicate the potential use of Q-CS as a raw material for antiseptic biomaterials.

Enhanced antimicrobial and antioxidant capacity of Thymus vulgaris, Lippia sidoides, and Cymbopogon citratus emulsions when combined with mannosylerythritol a lipid biosurfactant.

Essential oils (EOs) are natural and effective agents for controlling microorganisms which cause biodeterioration and disease. However, their application is hampered/restricted due to hydrophobicity and rapid vaporization of these compounds. Encapsulation technology provides an effective approach to maintain EO stabilization and prevent the loss of volatile ingredients. Meanwhile, using a synthetic surfactant is seen as counter-productive; therefore, a natural biosurfactant is more reasonable and can potentially increase activity due to its other biological proprieties. This work aims to evaluate the mannosylerythritol lipid (MEL) biosurfactant combined with Thymus vulgaris, Lippia sidoides, and Cymbopogon citratus essential oil emulsions (O/W) and evaluate its antimicrobial and antioxidant capacity. The biosurfactant MEL demonstrated activity against Bacillus subtilis and Penicillium sp. After emulsification, the antimicrobial activity of Thymus vulgaris and Lippia sidoides was increased against Escherichia coli (500 µg/mL), Staphylococcus aureus (600 µg/mL), Bacillus subtilis (120 µg/mL), Pseudomonas aeruginosa (1500 µg/mL), Penicillium sp. (62.25 µg/mL), Aspergillus flavus (250 µg/mL), Fusarium oxysporum (100 and 250 µg/mL), and Candida albicans (125 and 250 µg/mL). We report that emulsions prepared with MEL have high inhibitory activity, maintain the active concentration, and increase antioxidant capacity by 7.33% (Thymus vulgaris), 13.71% (Lippia sidoides), and 3.15% (Cymbopogon citratus).

Antiviral and antibacterial activity of sodium alginate/poly(diallyldimethylammonium chloride) polyelectrolyte film for packaging applications.

Pathogen agents, such as bacteria and virus, can contaminate plastic surfaces, particularly those used in food packaging. This study proposed to prepare a polyelectrolyte film with antiviral and antibacterial activity based on sodium alginate (SA) and poly(diallyldimethylammonium chloride) (PDADMAC), a cationic polymer with sanitizing properties. In addition, the physicochemical properties of the polyelectrolyte films were also evaluated. The polyelectrolyte films showed continuous, compact, and crack-free structures. The FTIR analysis confirmed the ionic interaction between SA and PDADMAC. Adding PDADMAC significantly affected the mechanical properties of the films (p < 0.05), increasing the maximum tensile strength (from 8.66 ± 1.55 MPa to 18.1 ± 1.77 MPa). However, polyelectrolyte films showed higher water vapor permeability values due to the strong hydrophilicity of PDADMAC, representing a 43 % average increase compared with the control film. Also, thermal stability improved with the incorporation of PDADMAC. The selected polyelectrolyte film inactivated 99.8 % of SARS-CoV-2 after 1 min in direct contact with the virus, in addition to having an inhibitory effect against Staphylococcus aureus and Escherichia coli bacteria. Therefore, this study demonstrated the efficacy of using PDADMAC in the preparation of polyelectrolyte sodium alginate-based films with improvements in physicochemical properties and especially with antiviral activity against SARS-CoV-2.

A study of the bioactive potential of seven neglected and underutilized leaves consumed in Brazil.

This study investigated the vitamin C content, total phenolic compounds (TPC), and the potential bioactivities (antioxidant, antiproliferative, antibacterial activities, and inhibition capacity against N-nitrosation) of seven neglected and underutilized species (NUS): culantro (Eryngium foetidum), false roselle (Hibiscus acetosella), roselle (Hibiscus sabdariffa), tree basil (Ocimum gratissimum), Barbados Gooseberry (Pereskia aculeata), purslane (Portulaca oleracea), and tannia (Xanthosoma sagittifolium). Phenolic-rich extracts were obtained by a sequential optimization strategy (Plackett-Burman and Central Composite Design). O. gratissimum presented the highest TPC and X. sagittifolium the greater total vitamin C content. Overall, the plant extracts presented promising bioactive capacities, as scavenging capacity against HOCl, H2O2 and ROO• induced oxidation. P. oleracea demonstrated the highest cytostatic effect against ovarian and kidney tumor cells. O. gratissimum effectively inhibited S. Choleraesuis growth. Maximum inhibition on n-nitrosation was showed by O. gratissimum and E. foetidum. These results highlight the studied NUS as sources of potential health-promoting compounds.

Control of Colletotrichum gloeosporioides (penz.) Sacc. In yellow passion fruit using Cymbopogon citratus essential oil.

The use of antibiotics in agriculture is limited when compared to their applications in human and veterinary medicine. On the other hand, the use of antimicrobials in agriculture contributes to the drug resistance of human pathogens and has stimulated the search for new antibiotics from natural products. Essential oils have been shown to exert several biological activities including antibacterial and antifungal actions. The aim of this study was to determine the activity of 28 essential oils from medicinal plants cultivated at CPMA (Medicinal and Aromatic Plants Collection), CPQBA/UNICAMP, against Colletotrichum gloeosporioides (Penz.) Sacc., the anthracnose agent in yellow passion fruit (Passiflora edulis Sims f. flavicarpa Deg), as well as evaluating their effect in the control of post-harvest decay. The oils were obtained by water-distillation using a Clevenger-type system and their minimal inhibitory concentrations (MIC) determined by the micro-dilution method. According to the results, 15 of the 28 essential oils presented activity against Colletotrichum gloeosporioides, and the following four oils presented MIC values between 0.25 and 0.3 mg/mL: Coriandrum sativum, Cymbopogon citratus, Cymbopogon flexuosus and Lippia alba. The evaluation of Cymbopogon citratus essential oil in the control of post-harvest decay in yellow passion fruit showed that the disease index of the samples treated with the essential oil did not differ (P ≤ 0.05) from that of the samples treated with fungicide. The present study shows the potential of Cymbopogon citratus essential oil in the control of the anthracnose agent in yellow passion fruit.

Use of Bacillus pumilus CBMAI 0008 and Paenibacillus sp. CBMAI 868 for colour removal from paper mill effluent.

Bacillus pumilus and Paenibacillus sp. were applied on the paper mill effluent to investigate the colour remotion. Inocula were individually applied in effluent at pH 7.0, 9.0 and 11.0. The real colour and COD remotion after 48h at pH 9.0 were, respectively, 41.87% and 22.08% for B. pumilus treatment and 42.30% and 22.89% for Paenibacillus sp. Gel permeation chromatography was used to verify the molar masses of compounds in the non-treated and treated effluent, showing a decrease in the compounds responsible for the paper mill effluent colour.

Purification and Partial characterization of manganese peroxidase from Bacillus pumilus AND Paenibacillus sp.

The production of manganese peroxidase (MnP) from Bacillus pumilus and Paenibacillus sp. was studied under absence and presence of the inducers indulin AT, guayacol, veratryl alcohol, lignosulfonic acid and lignosulfonic acid desulfonated. Indulin AT increased the activity of B. pumilus MnP up to 31.66 U/L after 8 h, but no improve was observed for Paenibacillus sp., which reached maximum activity (12.22 U/L) after 20 h. Both MnPs produced by these microorganisms were purified in phenyl sepharose resin and the proteins from crude extracts were eluted in two fractions. However, only the first fraction of each extract exhibited MnP activities. Tests in different pH and temperature values, from pH 5.0 to pH 10.0 and 30 °C to 60 °C, respectively, were carried out with the purified MnP. The maximum activity reached for B. pumilus and Paenibacillus sp. MnPs were 4.3 U/L at pH 8.0 and 25 °C and 11.74 U/L at pH 9.0 and 35 °C, respectively. The molar masses determined by SDS-PAGE gel eletrophoresis were 25 kDa and 40 kDa, respectively, for the purified enzyme from B. pumilus and Paenibacillus sp.

Antifungal, antibiofilm, and antiproliferative activities of Guapira graciliflora Mart.

The aim of this study was to evaluate in vitro the antifungal, antibiofilm and antiproliferative activities of the extract from the leaves of Guapira graciliflora Mart. The phytochemical characterization of the extract was performed using electrospray ionization mass spectrometry (ESI-MS). The antimicrobial activity of the extract and its fractions was evaluated using the broth microdilution method against species of Candida. The inhibition of C. albicans biofilm was evaluated based on the number of colony-forming units (CFU) and metabolic activity (MTT). The antiproliferative activity of the extract and its fraction was evaluated in the presence of human tumor and non-tumor cells, and the cytotoxicity of the extract was determined on the RAW 264.7 macrophage line - both using the sulforhodamine B method. The phytochemical characterization indicated the presence of the flavonoids rutin and kaempferol. The extract and the methanol fraction exhibited moderate antifungal activity against C. albicans, C. krusei, and C. glabrata, and strong activity against C. dubliniensis. In the biofilms at 24 and 48 hours, the concentration of 12500 µg/mL of the extract was the most effective at reducing the number of CFU s/mL (44.4% and 42.9%, respectively) and the metabolic activity of C. albicans cells (34.6% and 52%, respectively). The extract and its fractions had no antiproliferative effect on the tumor lines tested, with mean activity (log GI50) equal to or greater than 1.71 µg/mL. Macrophage cell viability remained higher than 80% for concentrations of the extract of up to 62.5 µg/mL. G. graciliflora has flavonoids in its chemical composition and demonstrates potential antifungal and antibiofilm activity, with no evidence of a significant change in the viability of human tumor and non-tumor cell lines.

Activity of essential oils from Brazilian medicinal plants on Escherichia coli.

Essential oils obtained from leaves of 29 medicinal plants commonly used in Brazil were screened against 13 different Escherichia coli serotypes. The oils were obtained by water-distillation using a Clevenger-type system and their minimal inhibitory concentration (MIC) were determined by microdilution method. Essential oil from Cymbopogon martinii exhibited a broad inhibition spectrum, presenting strong activity (MIC between 100 and 500 microg/mL) against 10 out of 13 Escherichia coli serotypes: three enterotoxigenic, two enteropathogenic, three enteroinvasive and two shiga-toxin producers. C. winterianus inhibited strongly two enterotoxigenic, one enteropathogenic, one enteroinvasive and one shiga-toxin producer serotypes. Aloysia triphylla also shows good potential to kill Escherichia coli with moderate to strong inhibition. Other essential oils showed antimicrobial properties, however with a more restricted action against the serotypes studied. Chemical analysis of Cymbopogon martinii essential oil performed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS) showed the presence of compounds with known antimicrobial activity, including geraniol, geranyl acetate and trans-cariophyllene, which tested separately, indicated geraniol as antimicrobial active compound. The significant antibacterial activity of Cymbopogon martinii oil suggests that they could serve as a source for compounds with therapeutic potential.

Linalool production from the leaves of Bursera aloexylon and its antimicrobial activity.

The oil of the leaves of Bursera aloexylon was found to contain a high linalool level (96.7 %). The antimicrobial activity tests indicated that the oil was effective against Rhodococcus equi (0.60 mg/ml) and Staphylococcus epidermides (0.15 mg/ml).

Encapsulated thyme (Thymus vulgaris) essential oil used as a natural preservative in bakery product.

The objective of this work was to design a particle using thyme (Thymus vulgaris) essential oil through complex coacervation. In vitro activity against bacteria and molds of free oil as well as the encapsulated oil was verified and then in situ assay was done. The free thyme oil presented high in vitro activity, with values below 0.50mg/mL for almost all the microorganisms tested. Also, MIC values for the encapsulated oil was lower than for the free oil, probably due to the protective micro-environment promoted by the particle wall. The microparticles applied to cakes samples conferred protection against the volatilization of the encapsulated oil and promoted a minimum shelf life of 30days without the use of synthetic preservatives.