Antimicrobial effect of Artemisia species on Pseudomonas aeruginosa

Antibiotic resistance has emerged as a severe problem in hospital-acquired infectious disease. The Gram-negative bacterium Pseudomonas aeruginosa is found to cause secondary infection in immune-compromised patients. Unfortunately, it is resistant to virtually all β-lactam antibiotics such as penicillin, cephalosporin and others. Researchers are seeking for new compounds to treat several antibiotic-resistant bacterial strains. Artemisia plant extracts are commonly used for their therapeutic properties by natives throughout dry regions of North and South America. Here, they are administered as an alternative medicine for stomach problems and other complex health issues. In this study, the antimicrobial effects of plant extracts from several Artemisia species as well as compounds dehydroleucodine and dehydroparishin-B (sesquiterpenes derived specifically from A. douglasiana) were used as treatments against the pathogenicity effects of P. aeruginosa. Results showed that both compounds effectively inhibit the secretion of LasB elastase, biofilm formation and type III secretion, but fail to control LasA protease. This is a significant observation because these virulent factors are crucial in establishing P.aeruginosa infection. The results from this study signify a plausible role for future alternative therapy in the biomedical field, which recommends DhL and DhP can be studied as key compounds against bacterial infections of Pseudomonas aeruginosa.

Caracterização química, atividade antioxidante e antimicrobiana do óleo essencial de Baccharis oreophila Malme

The Baccharis oreophila Malme belongs to the Asteraceae family. In Brazil are reported 120 species of Baccharis, most located in the South and Southeast regions, the latter presents the highest prevalence, especially in the state of São Paulo. Asteraceae is well known for the production of essential oils, which are liquid, volatile and aromatic substances produced by plants specialized for metabolism possess antibacterial, antifungal, and antioxidant properties. Thus, this study aimed, perform chemical and evaluate the antimicrobial and antioxidant activity of essential oil from dried leaves of B. oreophila collected in winter in Piraquara, Paraná. Obtaining essential oil was given by hydrodistillation in Clevenger apparatus, in triplicate, and the analysis was done using a gas chromatograph coupled to mass spectrometry GC / MS. The identification of the components was made based on retention indices calculated from the co-injection of a series of n-alkanes, followed by comparison of their mass spectra with literature. The antimicrobial activity was assessed by disk diffusion method and microdilution. The antioxidant activity was evaluated by the methods DPPH equivalent Trolox, ABTS and FRAP equivalent Trolox equivalent ferrous sulfate. The essential oil showed 0.47% yield. They identified 57 components (89.38%), 1.51% were classified as hydrogenated monoterpenes, oxygenated monoterpenes 15.14%, 34.84% and 37.87% hydrogenated sesquiterpenes sesquiterpenes oxygenates. As the major components were detected kusimono (16.37%), spathulenol (16.12%), the δ-cadinene (5.68%) and bicyclogermacrene (4.09%). The antimicrobial activity of essential oil was performed for the microorganisms Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Candida albicans ATCC 18804 and Candida tropicalis ATCC 13803, the results showed that the essential oil showed activity against S. aureus Inhibitory Concentration minimum (CIM) 1250 g/mL. In the evaluation of antioxidant activity essential oil showed antioxidant potential for the three methods evaluated, with values of 1,468 m.mol.L-1, 7.126 m.mol.L-1 and 45.515 m.mol.L-1 for ABTS, DPPH and FRAP, respectively. These results demonstrate that the essential oil of B. oreophila showed antimicrobial potential against S. aureus and interesting antioxidant activity, especially for the reducing power of iron ion, demonstrating their potential for future industrial applications. It is important to emphasize that were not observed in the literature reports highlighting such biological properties of B. oreophila oil.

Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons

The herbaceous shrub Tetradenia riparia has been traditionally used to treat inflammatory and infectious diseases. Recently, a study showed that T. riparia essential oil (TrEO) obtained in summer has antileishmanial effects, although these results could be influenced by seasonal variation. This study evaluated the activity of the TrEO obtained in different seasons against Leishmania (Leishmania) amazonensis , in vitro and in vivo. The compounds in the TrEO were analysed by gas chromatography-mass spectrometry; terpenoids were present and oxygenated sesquiterpenes were the majority compounds (55.28%). The cytotoxicity and nitric oxide (NO) production were also tested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitory concentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEO reduced intracellular amastigote infection, independently of season. The TrEO from plants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mL for J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NO production did not change in samples of the TrEO from different seasons. The antileishmanial effect in vivo consisted of a reduction of the parasite load in the spleen. These results suggest that the TrEO has potential effects on L. (L.) amazonensis, consonant with its traditional use to treat parasitic diseases.

Determination of borneol and other chemical compounds of essential oil of Dryobalanops aromatica exudate from Malaysia

Purpose: To determine borneol and other chemical compounds of essential oil derived from the exudate of Dryobalanops aromatica aromatica in Malaysia. Methods: Exudate was collected from D. aromatica and subjected to fractional distillation to obtain essential oil. Gas chromatography-mass spectrometry (GC-MS) was performed to characterize the composition of the isolated essential oil. Results: Essential oil (7.58 %) was obtained with the highest yield (3.24 %) in the first 2 h of fractional distillation. Thirty compounds which accounted for 97.56 % of total essential oil composition were identified by GC-MS, and they include sesquiterpenes (46.87 %), monoterpenes (31.05 %), oxygenated monoterpenes (16.76 %) and oxygenated sesquiterpenes (2.13 %). Borneol (0.74 %) was also detected in the essential oil. Conclusion: Borneol and other terpenoid compounds are present in the essential oil of the exudate of D. aromatica

Antibacterial and cytotoxic properties of isoprenoids from the red sea soft coral, Lobophytum sp

Purpose: To evaluate the antibacterial and cytotoxic activities of the secondary metabolites of Lobophytum sp. Methods: Maceration with methanol: chloroform (1:1) was applied to extract the coral material. Chromatographic and spectroscopic techniques were employed for fractionation, isolation and elucidation of pure compounds. Antibacterial activities were performed by well diffusion method against three Gram-positive and four Gram-negative bacteria. Brine shrimp lethality test was employed to predict toxicity, while antitumor activity were tested by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) method against Ehrlich carcinoma cells. Results: Four sesquiterpenes, one cembranoid type diterpenes and two steroids were isolated. 1 exhibited significant antibacterial activity against four tested bacteria (P. aeruginosa, S. aureus, S. epidermis, and S. pneumonia) with MIC value of 15 μg/mL. Moreover, 1 showed high diameter zone of inhibition ranging from 16 - 18 mm against test bacteria. Compounds 4 and 5 displayed moderate antibacterial activity against all test bacteria with inhibition zone diameter (IZD) ranging from 11 – 15 mm and MIC values of 30 μg/mL. 2, 3, 6 and 7 exhibited weak antibacterial activity (IZD, 7 - 11 mm; MIC ≥ 30 μg/mL). In addition, only diterpene compound (4) showed high toxicity against A. Salina and antitumor activity against Erhlich carcinoma cells with the LD50 of 25 and 50 μg/mL, respectively. Conclusion: This study reveals the strong antibacterial activity of sesquiterpene alismol (1) and the potential antibacterial and antitumor activity of cembranoid type diterpene, cembrene A (4).

Atividade antimalárica de plantas medicinais da biorregião do Araripe-CE em modelo murino - Plasmodium berghei

Malaria, also popularly known as maleita , intermittent fever, paludism, impaludism, third fever or fourth fever, is an acute infectious febrile disease, which, in human beings, is caused by four species: Plasmodium falciparum, P. vivax, P. malariae and P. ovale. Malaria, one of the main infectious diseases in the world, is the most important parasitoses, with 250 million annual cases and more than 1 million deaths per year, mainly in children younger than live years of age. The prophylactic and therapeutic arsenal against malaria is quite restricted, since all the antimalarials currently in use have some limitation. Many plant species belonging to several families have been tested in vivo, using the murine experimental model Plasmodium berghei or in vitro against P. falciparum, and this search has been directed toward plants with antithermal, antimalarial or antiinflammatory properties used in popular Brazilian bolk medicine. Studies assessing the biological activity of medicinal plant essential oils have revealed activities of interest, such as insecticidal, spasmolytic and antiplasmodic action. It has also been scientifically established that around 60% of essential oils have antifungal properties and that 35% exhibit antibacterial properties. In our investigation, essential oils were obtained from the species Vanillosmopsis arborea, Lippia sidoides and Croton zethneri which are found in the bioregion of Araripe-Ceará. The chemical composition of these essential oils was partially characterized and the presence of monoterpenes and sesquiterpenes. The acute toxicity of these oils was assessed in healthy mice at different doses applied on a single day and on four consecutive days, and in vitro cytotoxicity in HeLa and Raw cell lines was determined at different concentrations. The in vivo tests obtained lethal dose values of 7,1 mg/Kg (doses administered on a single day) and 1,8 mg/Kg (doses administered over four days) for 50% of the animals. In the in vitro tests, the inhibitory concentration for 50% of cell growth in Hela cell lines was 588 μg/mL (essential oil from C. zethneri after 48 h), from 340-555 μg/mL (essential oil from L. sidoides, after 24 and 48 h). The essential oil from V. arborea showed no cytotoxicity and none of the essential oils were cytotoxic in Raw cell lines. These data suggest a moderate toxicity in the essential XVIII oils under study, a finding that does not impede their testing in in vivo antimalarial assays. Was shown the antimalarial activity of the essential oils in mice infected with P. berghei was assessed. The three species showed antimalarial activity from 36%-57% for the essential oil from the stem of V. arborea; from 32%-82% for the essential oil from the leaves of L. sidoides and from 40%-70% of reduction for the essential oil from the leaves of C. zethneri. This is the first study showing evidence of antimalarial activity with these species from northeast Brazil. Further studies to isolate the active ingredients of these oils are needed to determine if a single active ingredient accounts for the antimalarial activity or if a complex integration of all the compounds present occurs, a situation reflected in their biological activity

Thermal tool for evaluation of essential oils of Eucalyptus spp susceptible and resistant to Glycaspis brimblecombei attack.

Eucalyptus spp genus is economically important to different industry fields. There are pests that damage the development of eucalypts and Glycaspis brimblecombei, a sap-sucking insect, is one of them. Studies about this insect attack to the eucalypts showed preferences. This work aim was to compare the preferences of the insect with thermoanalytical characteristics of different eucalypts (susceptible, less susceptible and resistant to Glycaspis brimblecombei) essential oils. The leaves of six species of Eucalyptus were crushed and the essential oil was extracted using Clevenger apparatus. The Shimadzu DTG-60H was used to analyze the samples. The results showed that the samples from more susceptible eucalypts had total mass loss at about 124ºC to 156ºC, lower than samples from more resistant eucalypts (from 168ºC to 175ºC). Furthermore, the study suggests that the susceptibility or the resistance of eucalypts to the pest may be related to their essential oil composition and concentration of monoterpenes and sesquiterpenes.