Phytochemical prospection,evaluation of antibacterial activity and toxicity of extracts of Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz

Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz is a arboreal species found in the Caatinga from Northeast of Brazil that has been used in popular medicine as an anti-inflammatory, healing, analgesic and for the treatment of respiratory system disorders. Therefore, the objective of this work was to evaluate the composition of ethanol extracts from the leaves and inner bark of Libidibia ferrea, as well as to verify its antibacterial activity and as a potential inhibitor of the TetK efflux pump in Staphylococcus aureus strains, in addition to investigating the toxicity of the extracts in a Drosophila melanogaster model. The analysis and quantification of the extracts markers was performed by High Performance Liquid Chromatography (HPLC). To determine the Minimum Inhibitory Concentration (MIC) broth microdilution tests were carried out. The evaluation of efflux pump inhibition was performed by modifying the MIC of antibiotics and ethidium bromide. Mortality and negative geotaxis tests were used to verify the toxicity of extracts on D. melanogaster. Hydrolysable tannins (gallic acid and ellagic acid) and flavonoids were found in HPLC analysis. The extracts did not show antibacterial activity, demonstrating a MIC ≥ 1024 µg/mL, however the ethanolic extract of the leaves decreased the MIC of the antibiotic from 64 µg/mL to 16 µg/mL, but this effect is not associated with the inhibition of the efflux pump. The extracts did not show toxicity in a D. melanogaster model. This is the first study to evaluate the antibacterial activity of L. ferrea extracts on the IS-58 strain of S. aureus, as well as the first to investigate its toxicity using D. melanogaster. From the results, further studies are needed to determine the mechanisms of action of the extract with other antibiotics.     

Chemical Composition and Antioxidant Activity of Essential Oils from Leaves of Two Specimens of Eugenia florida DC.

Eugenia florida DC. belongs to the Myrtaceae family, which is present in almost all of Brazil. This species is popularly known as pitanga-preta or guamirim and is used in folk medicine to treat gastrointestinal problems. In this study, two specimens of Eugenia florida (Efl) were collected in different areas of the same region. Specimen A (EflA) was collected in an area of secondary forest (capoeira), while specimen B (EflB) was collected in a floodplain area. The essential oils (EOs) were extracted from both specimens of Eugenia florida by means of hydrodistillation. Gas chromatography coupled to mass spectrometry (GC/MS) was used to identify the volatile compounds present, and the antioxidant capacity of the EOs was determined by antioxidant capacity (AC-DPPH) and the Trolox equivalent antioxidant (TEAC) assay. For E. florida, limonene (11.98%), spathulenol (10.94%) and α-pinene (5.21%) were identified as the main compounds of the EO extracted from sample A, while sample B comprised selina-3,11-dien-6α-ol (12.03%), eremoligenol (11.0%) and γ-elemene (10.70%). This difference in chemical composition impacted the antioxidant activity of the EOs between the studied samples, especially in sample B of E. florida. This study is the first to report on the antioxidant activity of Eugenia florida DC. essential oils.     

Complementary and Comparative Study on Hypoglycemic and Antihyperglycemic Activity of Various Extracts of Eugenia jambolana Seed, Momordica charantia Fruits, Gymnema sylvestre, and Trigonella foenum graecum Seeds in Rats

In present study, we investigated hypoglycemic and antihyperglycemic potential of five extracts (water, ethanol, methanol, hexane, and chloroform) of four plants (i.e., seeds of Eugenia jambolana, fruits of Momordica charantia, leaves of Gymnema sylvestre, and seeds of Trigonella foenum graecum) alone and/or in combination with glimepiride in rats. Ethanol extract of E. jambolana, water extract of M. charantia, ethanol extract of G. sylvestre, and water extract of T. graecum exhibited highest hypoglycemic and antihyperglycemic activity (most active) in rats among all the extracts, while hexane extracts exhibited least activities. Most active extracts were further studied to dose-dependent (200, 100, and 50 mg/kg body weight (bw)) hypoglycemic and antihyperglycemic effects alone and in combination with glimepiride (20, 10, and 5 mg/kg bw). The combination of most active extracts (200 mg/kg bw) and lower dose of glimepiride (5 mg/kg bw) showed safer and potent hypoglycemic as well as antihyperglycemic activities without creating severe hypoglycemia in normal rats, while higher doses (200 mg/kg bw of most active extracts, and 10 and 20 mg/kg bw of glimepiride) were generated lethal hypoglycemia in normal rats. From this study, it may be concluded that the ethanol extract of E. jambolana seeds, water extract of M. charantia fruits, ethanol extract of G. sylvestre leaves, and water extract of T. graecum seeds have higher hypoglycemic and antihyperglycemic potential and may use as complementary medicine to treat the diabetic population by significantly reducing dose of standard drugs.     

Anthemis cotula L. from Jordan: Essential oil composition,LC-ESI-MS/MS profiling of phenolic acids - flavonoids and in vitro antioxidant activity

Essential oils of the leaves and flowers of Anthemis cotula L. (family Asteraceae) grown in Jordan were extracted by hydro-distillation and then analyzed by GC–MS. Sesquiterpenes hydrocarbons (SH) were the dominant components in the oils extracted from leaves and flowers of A. cotula. γ-Muurolene and aromadendrene, were the major compounds that were obtained from the flowers oil, while γ-muurolene and trans-cadinene ether were detected as major ingredients in the leaves extract. LC-MS analysis was carried out to identify the significant compounds from each extract. Additionally, butanol (B), aqueous methanol (M) and water (W) extracts prepared from the flowers and the leaves of A. cotula were analysed by LC-MS/MS. Apigenin and chlorogenic acid were the main constituents detected in the flowers’ alcoholic extracts and leaves’ aqueous extract. Moreover, the essential oils and all prepared extracts were assayed for their total antioxidant activity using the DPPH, ABTS, and ferrous ion chelating effect (FIC) assay methods. All investigated oils and extracts showed interesting activity as compared to the positive controls employed (α-tocopherol and ascorbic acid).     

Myorelaxant Effect of the Dysphania ambrosioides Essential Oil on Sus scrofa domesticus Coronary Artery and Its Toxicity in the Drosophila melanogaster Model

Purpose: Alternative methods for the use of animals in research have gained increasing importance, due to assessments evaluating the real need for their use and the development of legislation that regulates the subject. The principle of the 3R’s (replacement, reduction and refinement) has been an important reference, such that in vitro, ex vivo and cord replacement methods have achieved a prominent place in research. Methods: Therefore, due to successful results from studies developed with these methods, the present study aimed to evaluate the myorelaxant effect of the Dysphania ambrosioides essential oil (EODa) using a Sus scrofa domesticus coronary artery model, and the toxicity of both the Dysphania ambrosioides essential oil and its major constituent, α-terpinene, against Drosophila melanogaster in toxicity and negative geotaxis assays. Results: The EODa relaxed the smooth muscle of swine coronary arteries precontracted with K⁺ and 5-HT in assays using Sus scrofa domesticus coronary arteries. The toxicity results presented LC₅₀ values of 1.546 mg/mL and 2.282 mg/mL for the EODa and α-terpinene, respectively, thus showing the EODa and α-terpinene presented toxicity to these dipterans, with the EODa being more toxic. Conclusions: Moreover, the results reveal the possibility of using the EODa in vascular disease studies since it promoted the relaxation of the Sus scrofa domesticus coronary smooth muscle.     

右旋糖甙缩硫醛大环螯合剂的合成及解汞毒性能

合成了一种新的选择性螯合汞的水溶性高分子缩硫醛大环树脂,由醛基化右旋糖甙与乙二醇二巯基乙酸酯缩合而得。进行了这种高分子螯合剂的毒性和对氯化汞急性中毒的解毒能力的初步动物试验。结果表明整合剂本身毒性很小,并能提高中毒小白鼠的存活率。如作为处置汞中毒的口服药物,它既可经尿排汞,也可由切断肝肠循环而随粪便排汞。     

Essential Oils as In Vitro Ruminal Fermentation Manipulators to Mitigate Methane Emission by Beef Cattle Grazing Tropical Grasses

There is increasing pressure to identify natural feed additives to mitigate methane emissions from livestock systems. Our objective was to investigate the effects of essential oils (EO) extracts star anise (Illicium verum), citronella (Cymbopogon winterianus), clove bud (Eugenia caryophyllus), staigeriana eucalyptus (Eucalyptus staigeriana), globulus eucalyptus (Eucalyptus globulus), ginger (Zingiber officinale), ho wood (Cinnamomum camphora), melaleuca (Melaleuca alternifolia), oregano (Origanum vulgare) and white thyme (Thymus vulgaris) on in vitro methane emissions from four rumen-cannulated Nellore cattle grazing a tropical grass pasture as inoculum donors. The semi-automated gas production technique was used to assess total gas production, dry matter degradability, partitioning factor, ammoniacal nitrogen, short-chain fatty acids and methane production. All essential oils were tested in four doses (0, 50, 250 and 500 mg/L) in a randomized block design, arranged with four blocks, 10 treatments, four doses and two replicates. Within our study, oregano and white Thyme EO reduced net methane production at 250 mg/L, without affecting substrate degradation. Essential oils from oregano and white thyme have the potential to modify ruminal fermentation and suppress rumen methanogenesis without negative effects on feed digestibility, indicating promise as alternatives to ionophores for methane reduction in beef cattle.     

Chemical Composition,Insecticidal and Mosquito Larvicidal Activities of Allspice (Pimenta dioica) Essential Oil

Essential oils are biologically and environmentally safe pesticidal compounds yielded from aromatic plants. Spices are important sources of essential oils, and they are widely used in the medicine, food, and various other industries. Among the different spices, Allspice (Pimenta dioica) is underexplored in terms of its biological efficacy and a limited number of studies are available on the chemical composition of Allspice essential oil (AEO); thus, the present study evaluated the larvicidal property, the repellency, and the fumigant toxicity against common pests of stored products of AEO. AEO was found to inhibit the survival of larvae of such vectors as Aedis, Culex, and Armigeres species. Further, AEO was found to exert repellant effects against the pests of such stored products as Sitophilus, Callosobruchus, and Tribolium. Similarly, the fumigant toxicity was found to be high for AEO against these species. The contact toxicity of AEO was high against Sitophilus and Callosobruchus. Apart from that, the essential oil was found to be safe against a non-target organism (guppy fishes) and was found to be non-genotoxic in an Allium cepa model. Overall, the results of the present study indicate that the essential oil from Allspice could be used as an environmentally safe larvicidal and biopesticidal compound.     

Chemical Composition and Evaluation of Insecticidal Activity of Calendula incana subsp. maritima and Laserpitium siler subsp. siculum Essential Oils against Stored Products Pests

The problems of the environment and human health related to the use of synthetic and broad-spectrum insecticides have increasingly motivated scientific research on different alternatives and among these, the use of green systems, such as essential oils, have been explored. Several species of the Apiaceae and Asteraceae families, aromatic herbs rich in secondary bioactive metabolites, are used in the industrial field for pharmaceutical, cosmetic, and food purposes. Different essential oils extracted from some species of these families have shown acute toxicity and attractive and/or repellent effects towards different insects. In our work, we investigated the toxic potential of Calendula incana subsp. maritima and Laserpitium siler subsp. siculum essential oils against four insect species, Sitophilus oryzae, Lasioderma serricorne, Necrobia rufipes, and Rhyzoperta dominica, which are common pests of stored products. The composition of both oils, extracted by hydrodistillation from the aerial parts of the two plants, was evaluated by GC×GC-MS. Calendula incana subsp. maritima essential oil was rich in oxygenated sesquiterpenoids, such as cubebol (35.39%), 4-epi-cubebol (22.99%), and cubenol (12.77%), while the Laserpitium siler subsp. siculum essential oil was composed mainly of monoterpene hydrocarbons, such as β-phellandrene (42.16%), limonene (23.87%), and β-terpinene (11.80%). The toxicity Petri dish bioassays indicated that C. maritima oil killed a mean of 65.50% of S. oryzae and 44.00% of R. dominica adults, indicating a higher biocidal activity in comparison with L. siculum oil, while toward the other species, no significant differences in mortality were recorded. Calendula maritima oil could be, then, considered a promising candidate for further tests as an alternative biocide toward S. oryzae and R. dominica. The possibility that the relatively high content of oxygenated sesquiterpenoids in C. maritima essential oil determines its higher biocidal activity is discussed.     

Phytochemical investigation,physicochemical characterization,and antimicrobial activities of Ethiopian propolis

Propolis is a natural resin substance produced by honeybees by collecting from parts of plants, buds, and exudates that are used for several biological activities such as antimicrobial, and fungicide functions. This study aimed to analyze the phytochemical, physicochemical, and antimicrobial activity of propolis collected from Boji Dirmaji and Fincha’a districts of western Ethiopia. The physicochemical characteristics, phytochemical screening, and antimicrobial activity of Ethiopian propolis against Aspergillus niger, Escherichia coli, and Staphylococcus aureus were evaluated using the disk diffusion method from its essential oils and crude ethanol extract were evaluated based on standard procedures. The results indicated that propolis was rich in saponins, tannins, flavonoids, steroids, triterpenes, and glycosides. Physicochemically, n-hexane extractable substances ranged between 8.6 and 33.9%, resins soluble 14.8–16.8%, insoluble residues 70.8–85.5%, moisture 1.7–4.6%, and ash content 2.8–9.7%, and 4.8 pH. The antimicrobial activities of essential oils propolis were active against Escherichia coli with an average inhibition zone of 18.3 ± 0.52 mm and 18.9 ± 0.06 mm at concentrations of 10 and 20 μl in Dirmaji districts. Moreover, the crude ethanol extracted propolis had nearly the same effect of inhibition to Escherichia coli. However, both crude extract and its essential oils didn’t show any activity on Staphylococcus aureus and Aspergillus niger. The analyzed propolis is promising antimicrobial activity from Gram-negative which is very notorious for people of the world.     

Phytochemical analysis,UPLC-ESI-Orbitrap-MS analysis,biological activity,and toxicity of extracts from Tripleurospermum limosum (Maxim.) Pobed

Tripleurospermum limosum (TL) has been used in folk medicine to treat gastritis. Toward the further development and use of TL, we report the phytochemical profiling, determination of active components, and antioxidant and enzyme inhibitory activities of TL. Nineteen compounds were identified by ultra-performance liquid chromatography-electrospray ionization-orbitrap-mass spectrometry for the first time in this plant. Phytochemical studies indicated that TL contained 11 types of phytochemicals. The active components [total carbohydrate content (TCC), total protein content (TP_roC), total triterpenoid content (TTC), total phenolic content (TP_heC), total flavonoid content (TFC), total phenolic acid content (TPAC), condensed tannin content (CTC), and gallotannin content (GC)] of eight different solvent extracts were determined by ultraviolet–visible spectrophotometry. Aqueous extract had highest TP_roC, TP_heC, and GC values. Methanol extract exhibited highest TCC and TFC values. Ethanol extract showed highest TPAC and CTC values and dichloromethane extract exhibited highest TTC value. Methanol extract showed strongest ability to scavenge 2,2-diphenyl-1-picrylhydrazyl radicals, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt cation radicals, and hydroxyl radicals, and also exhibited highest antioxidant activity in ferric-reducing antioxidant power and cupric ion-reducing antioxidant capacity assays. Best iron and copper chelating activity and H₂O₂ scavenging ability were shown by aqueous extract. Ethanol extract showed strongest ability to scavenge superoxide radicals and effectively prevent β-carotene bleaching. Acetone extract had highest inhibitory activity toward α-glucosidase, α-amylase, and xanthine oxidase. Ethyl ether extract had highest inhibitory activity towards urease and angiotensin converting enzyme. Aqueous and ethanol extracts had strongest inhibitory activity toward acetylcholinesterase. Methanol extract showed highest inhibitory activity toward tyrosinase. Methanol extract showed good stability and antioxidant capacity during heating, at different pH values, and after in vitro digestion and had low toxicity. The efficacy of methanol extract in stabilizing olive and sunflower oils was studied, the results suggested that methanol extract had a protective effect on the primary oxidation of the two oils. TL may be useful as a source of active components for application in human nutrition and/or phytomedicine and methanol extract of TL could be used as a natural oil stabiliser.     

Encapsulation of Eucalyptus largiflorens Essential Oil by Mesoporous Silicates for Effective Control of the Cowpea Weevil,Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae)

Although the use of synthetic chemicals is the principal method for insect pest management, their widespread application has led to numerous side effects, including environmental pollution and threats to human and animal health. Plant essential oils have been introduced as promising natural substitutes for synthetic insecticides. However, high volatility and/or low durability are the main limiting factors for essential oil application for control of insect pests. Accordingly, along with an evaluation of the fumigant toxicity of Eucalyptus largiflorens essential oil against the cowpea weevil, Callosobruchus maculatus, essential oil was nanoencapsulated by two mesoporous silicates, MCM-41 and zeolite 3A, to enhance fumigant persistence and toxicity. The chemical profile of essential oil was also analyzed through gas chromatographic-mass spectrometry. E. largiflorens essential oil showed significant concentration-dependent toxicity against insect pests; a concentration of 5.16 μL/L resulted in 100% mortality after 48 h. The toxicity of essential oil could be attributed to the presence of various insecticidal terpenes, such as spathulenol (15.6%), cryptone (7.0%), and 1,8-cineole (5.8%). Fumigant persistence was increased from 6 days to 19 and 17 days for pure and capsulated essential oil with MCM-41 and Zeolite 3A, respectively. The insect mortality also increased from 99 insects in pure essential oil to 178 and 180 insects in MCM-41 and Zeolite 3A encapsulated formulations, respectively. Therefore, the encapsulation of E. largiflorens essential oil by MCM- 41 and Zeolite 3A is a beneficial method for enhancing its persistence and toxicity against C. maculatus.     

Chemical composition and evaluation of the antimicrobial activity of the essential oil from leaves of Eugenia platysema

This study describes the qualitative and quantitative chemical composition and evaluates the antibacterial activity of essential oil from Eugenia platysema leaves. Analysis by GC–FID and GC–MS allowed the identification of 22 compounds. Different from the other species of the Eugenia genus, the major compound found in the essential oil was the diterpene phytol (66.05%), being this the first report of the presence of this compound in the essential oils from Eugenia genus. The sesquiterpene elixene was the second most concentrated compound in the studied essential oil (9.16%). The essential oil from E. platysema was tested for its antibacterial activity against cell-walled bacteria and mollicute strains of clinical interest using the microdilution broth assay. The results showed that the essential oil of E. platysema was inactive until 1000 μg mL^?1 against tested bacteria.     

Flavanone Glycosides,Triterpenes, Volatile Compounds and Antimicrobial Activity of Miconia minutiflora (Bonpl.) DC. (Melastomataceae)

Chemical composition of the essential oils and extracts and the antimicrobial activity of Miconia minutiflora were investigated. The flavanone glycosides, pinocembroside and pinocembrin-7-O-[4″,6″-HHDP]-β-D-glucose, were identified, along with other compounds that belong mainly to the triterpene class, besides the phenolics, gallic acid and methyl gallate. Sesquiterpenes and monoterpenes were the major compounds identified from the essential oils. Screening for antimicrobial activity from the methanolic extract of the leaves showed that the MIC and MMC values against the tested microorganisms ranged from 0.625 to 5 mg·mL⁻¹ and that the extract was active against microorganisms, Staphyloccocus aureus, Escherichia coli, and Bacillus cereus.     

Novel mercury(II) complexes of meso-tetraphenylporphyrin and N-methylporphyrins

Treatment of meso-tetraphenylporphyrin, H₂TPP, with just over one equivalent of mercury(II) acetate in methylene chloride-THF gives mercury(II) meso-tetraphenylporphyrin, HgTPP. With excess of mercury(II) acetate, H₂TPP and HgTPP afford a novel dimetallic mononuclear porphyrin, AcOHgTPPHgOAc. In contrast, HgTPP reacts with mercury(II) chloride to give the chloro-analogue, ClHgTPPHgCl, but there is no reaction between H₂TPP and mercury(II) chloride. Demetallation of HgTPP in methylene chloride containing small amounts of hydrogen chloride proceeds via the dimetallic compound, ClHgTPPHgCl, to give free base HTPP. The reaction rate is dependent upon acid concentration suggesting that the rate determining step is protonation, but dilution causes no decrease in the rate; a mechanism which invokes the intermediacy of monohydrogen-meso-tetraphenylporphyrinatomercury(II) chloride, H(TPP)HgCl, in the formation of ClHgTPPHgCl and in its subsequent decomposition into H₂TPP, is proposed.N-Methylporphyrins react with mercury(II) acetate in methylene chloride-tetrahydrofuran to give the corresponding N-methylporphyrinatomercury(II) acetates, Me(P)HgOAc.     

Rapid analysis of the essential oils from dried Illicium verum Hook. f. and Zingiber officinale Rosc. by improved solvent-free microwave extraction with three types of microwave-absorption medium

A new method of extracting essential oils from dried plant materials has been studied. By adding a microwave-absorption medium (MAM) to a reactor, solvent-free microwave extraction (SFME) was improved and can be used to extract essential oils from dried plant material without pretreatment. With a microwave irradiation power of 85 W it took only approximately 30 min to extract the essential oils completely. The whole extraction process is simple, rapid, and economical. Three types of MAM, iron carbonyl powder (ICP), graphite powder (GP), and activated carbon powder (ACP), and two types of dried plant material, Illicium verum Hook. f. and Zingiber officinale Rosc., were studied. The results were compared with those obtained by use of conventional SFME, microwave-assisted hydrodistillation (MAHD), and conventional hydrodistillation (HD), and the conclusion drawn was that improved SFME was a feasible means of extracting essential oils from dried plant materials, because there were few differences between the composition of the essential oils extracted by improved SFME and by the other methods.     

Potentiality of independent component regression in assessment of the peaks responsible for antimicrobial activity of <Emphasis Type="Italic">Satureja hortensis</Emphasis> L. and <Emphasis Type="Italic">Oliveria decumbens</Emphasis> Vent. using GC–MS

Satureja hortensis L. and Oliveria decumbens Vent. are used in traditional medicine in the world due to its antifungal, antibacterial and antioxidant properties. In this study, the antimicrobial activities in Satureja hortensis L. and Oliveria decumbens Vent. essential oils against three microbial strains were evaluated by two different methods, including: disk diffusion method and micro-broth dilution assay [with minimal inhibitory concentration (MIC) between 0.025 and 0.500 µL/mL, and minimal lethal concentration (MLC) between 0.050 and 1.000 µL/mL] and qualitative analysis was performed by gas chromatography–mass spectrometry technique (GC–MS). The peaks potentially responsible for the antimicrobial activity in essential oils samples were indicated by some linear multivariate calibration techniques with different preprocessing methods. From the studied techniques, independent component regression (ICR) was preferred to exhibit the potential antimicrobial active compounds in Satureja hortensis L. and Oliveria decumbens Vent. essential oils because of its high repeatability, simplicity, and interpretability of the regression coefficients. Independent components (ICs) can give more chemical explanation than principal components (PCs), because independence is a high-order statistic that is a much stronger condition than orthogonality.     

Chemical Composition and Antifungal Activity of Myrcia multiflora and Eugenia florida Essential Oils

The essential oils of three specimens of Myrcia multiflora (A, B and C) and Eugenia florida were extracted by hydrodistillation, and the chemical compositions from the essential oils were identified by gas chromatography and flame ionization detection (CG/MS and CG-FID). The fungicide potential of the EOs against five fungicide yeasts was assessed: Candida albicans INCQS-40175, C. tropicalis ATCC 6258, C. famata ATCC 62894, C. krusei ATCC 13803 and C. auris IEC-01. The essential oil of the specimen Myrcia multiflora (A) was characterized by the major compounds: α-bulnesene (26.79%), pogostol (21.27%) and δ-amorphene (6.76%). The essential oil of the specimen M. multiflora (B) was rich in (E)-nerolidol (44.4%), (E)-γ-bisabolene (10.64%) and (E,E)-α-farnesene (8.19%), while (E)-nerolidol (92.21%) was the majority of the specimen M. multiflora (C). The sesquiterpenes seline-3,11-dien-6-α-ol (12.93%), eremoligenol (11%) and γ-elemene (10.70%) characterized the chemical profile of the EOs of E. florida. The fungal species were sensitive to the essential oil of M. multiflora (B) (9–11 mm), and the lowest inhibitory concentration (0.07%) was observed in the essential oil of M. multiflora (A) against the yeasts of C. famata. Fungicidal action was observed in the essential oils of M. multiflora (A) against C. famata, with an MIC of 0.78 µL/mL and 3.12 µL/mL; C. albicans, with an MFC of 50 µL/mL and M. multiflora (C) against C. albicans; and C. krusei, with a MFC of 50 µL/mL.     

Composition,Anti-MRSA Activity and Toxicity of Essential Oils from Cymbopogon Species

Many of the essential oils obtained from medicinal plants possess proven antimicrobial activity and are suitable for medicinal purposes and applications in the food industry. The aim of the present work was the chemical analysis of 19 essential oils (EOs) from seven different Cymbopogon species (C. nardus, C. citratus, C winterianus, C. flexuosus, C. schoenanthus, C. martinii, C. giganteus). Five different chemotypes were established by GC/MS and TLC assay. The EOs, as well as some reference compounds, i.e., citronellol, geraniol and citral (neral + geranial), were also tested for their antimicrobial and antibiofilm activity against methicillin-resistant Staphylococcus aureus (MRSA) by the microdilution method and direct bioautography. The toxicity of EOs was evaluated by Danio rerio ‘Zebrafish’ model assay. All examined EOs showed moderate to high activity against MRSA, with the highest activity noted for C. flexuosus—lemongrass essential oil, both in microdilution and direct autobiography method. Significant difference in the toxicity of the examined EOs was also detected.     

Influence of different extraction methods on the yield and linalool content of the extracts of Eugenia uniflora L

This work has been developed using a sylvestral fruit tree, native to the Brazilian forest, the Eugenia uniflora L., one of the Mirtaceae family. The main goal of the analytical study was focused on extraction methods themselves. The method development pointed to the Clevenger extraction as the best yield in relation to SFE and Soxhlet. The SFE method presented a good yield but showed a big amount of components in the final extract, demonstrating low selectivity. The essential oil extracted was analyzed by GC/FID showing a large range of polarity and boiling point compounds, where linalool, a widely used compound, was identified. Furthermore, an analytical solid phase extraction method was used to clean it up and obtain separated classes of compounds that were fractionated and studied by GC/FID and GC/MS.