1,720,976 research outputs found
Chemotype of damask rose with oleic acid (9 octadecenoic acid) and its antimicrobial effectiveness
Full text linkEssential oils are natural products that have great antimicrobial potential value against many fungi and bacteria. Rosa damascena Mill. is one of the most important aromatic species of the Rosaceae family from which essential oil and economically valuable products can be obtained. The present study was designed to investigate the major compositions of the essential oil of this plant in Isfahan region of Iran and to identify its antibacterial and antifungal effects against 11 microorganisms causing human diseases and food spoilage. The essential oil was extracted by using the Clevenger apparatus and was analyzed by gas chromatography-mass spectrometry (GC–MS) technique. Its antimicrobial activity was evaluated by well diffusion, minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC). The results showed that the most important compounds of the essential oil were nonadecane (24.72%), heneicosane (19.325%), oleic acid (17.63%), and citronellol (12.61%). The results also showed that the highest inhibition zone of rose essential oil was against Aspergillus brasiliensis (15.00 ± 0.00 mm) and had a significant effect on Klebsiella pneumoniae (~ 8.00 mm). Also the rose oil had a significant inhibition and lethal effect against Candida albicans (MIC and MBC ~ 125 μg/mL), which is equivalent to the nystatin antibiotic (~ 125 μg/mL). Therefore, the essential oil of Damask rose can be considered as an alternative natural product for the prevention and treatment of fungal diseases in humans and against food spoilage as well
Chemical composition and antimicrobial activity of essential oils obtained from leaves and flowers of Salvia hydrangea DC. ex Benth.
No full textThe majority of essential oils obtained from vascular plants have been demonstrated to be effective in treating fungal and bacterial infections. Among others, Salvia hydrangea is an endemic half-shrub belonging to the Lamiaceae family that has been widely used from ancient times in Iranian traditional medicine. The aim of this study was to compare the composition and antimicrobial properties of essential oils obtained from leaves or flowers of this plant, collected from the Daran region of Iran during June 2018. The oils were obtained using Clevenger apparatus, their composition was evaluated by means of gas chromatography/mass spectrometry (GC/MS) and the antimicrobial properties were assayed by measuring inhibition halos, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The yield of leaf oil was ~ 0.25% and that of flower oil was ~ 0.28%. Oil composition was affected by the part of the plants used: the most abundant bioactives contained in leaf essential oil were (+)-spathulenol (16.07%), 1,8-cineole (13.96%), trans-caryophyllene (9.58%), β-pinene (8.91%) and β-eudesmol (5.33%) and those in flower essential oil were caryophyllene oxide (35.47%), 1,8-cineole (9.54%), trans-caryophyllene (6.36%), β-eudesmol (4.11%), caryophyllenol-II (3.46%) and camphor (3.33%). Both the oils showed a significant inhibitory and lethal effect on the Gram-negative bacteria Pseudomonas aeruginosa (MIC ~ 16 μg/mL), Shigella dysenteriae and Klebsiella pneumoniae (MIC ~ 62 μg/mL). Therefore, the essential oils obtained from both leaves and flowers of S. hydrangea may have potential application as bactericidal agents against some bacteria
Effects of ecological factors on the antioxidant potential and total phenol content of Scrophularia striata Boiss
Full text linkScrophularia striata, commonly known as figwort, is one of the most important medicinal plants that mainly grows in cold regions of the Zagros Mountains (West of Iran). Although the chemical composition of this plant species has not yet been explored, people living in Ilam province (W Iran) have used it for many years to treat different illnesses. The present study aims to analyze the effect of some ecological factors on the antioxidant potential and the amount of phenol present in this plant species, using a random factorial design with two factors (elevation and region) and three replicates. The fruits of the plant were gathered from three different elevations. They were collected from three regions of the Ilam province (Badreh, Dareshahr, and Dehloran) in June 2016, when the fruits appear. Moreover, to analyze different soil chemical and physical features, soil samples were gathered from a depth of 0.5 m under the shrubs. The antioxidant action of the methanol extract from the plant samples and the total amount of phenol compounds were measured using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and the Folin-Ciocalteu method, respectively. The results showed that the effects of site and elevation, and the interaction between these factors, on the antioxidant potential and total phenol amount were significant with a probability of error of 1%. The maximum extract efficiency (19.37 ± 3.07%), antioxidant potential (126.5656 ± 0.96 μg/mL), and total amount of phenol (55.7689 ± 3.17 μg/mL) were obtained from Dareshahr at an elevation of 600 m above mean sea level. The minimum amount of total phenol (24.6544 ± 3.21 μg/ml) was recorded at the lowest elevation of Badreh, at which phosphorus, potassium, organic carbon, organic material, nitrogen, acidity, lime, and silt were present at the lowest amount. However, the antioxidant activity and total amount of phenol had a strong direct correlation in the two districts of Dareshahr and Badreh, but were reversely and strongly correlated in Dehloran. Therefore, it can be stated that Scrophularia striata has the potential for antioxidant activity, however, the complexity of the effect of ecological factors on one hand, and the emergence of different chemical processes in the plant under such effects on the other hand, has led to the synthesis of different compounds with antioxidant potential in the plant in different regions
Variability in chemical composition and antimicrobial activity of essential oil of Rosa x damascena Herrm. from mountainous regions of Iran
Full text linkBackground: Essential oil of Rosa x damascena Herrm. is one of the most valuable and important raw materials for the flavor and fragrance industry. The cultivation of this plant has ancient origins, and Kashan was one of the first mountainous regions of Iran dealing with the cultivation of R. x damascena. In this study, both chemical composition and antimicrobial activity of different rose essential oils obtained from five mountainous areas of Kashan region (Maragh, Qamsar, Sadeh, Javinan, and Kamoo) has been investigated along with the influence of the environmental conditions on these properties.Results: Results showed that yield and chemical composition of essential oils obtained from Rosa x damascena were significantly affected by the collection area. In particular, the yield of oils varied from similar to 0.08 to similar to 0.132% and citronellol (36.70-9.18%), geraniol (12.82-0.47%), nonadecane (22.73-10.36%), heneicosane (31.7-11.43%), and 1-nonadecene (6.03-3.93%) have been detected as main compounds in all the plants collected, but at different concentrations depending on the collection area. The best fragrance and the highest yield were found in the oil from Kamoo area. Similarly to the chemical composition, the antimicrobial activity of the essential oils was affected by their origin, and essential oil obtained from plants collected from Kamoo area disclosed the highest antibacterial and antifungal efficacy. Its inhibition halos were 17.33 +/- 0.58 mm against Aspergillus brasiliensis, 15.67 +/- 0.58 mm against Staphylococcus aureus, and 12.33 +/- 0. 58 mm against Streptococcus pyogenes. Essential oils of R. damascena were also effective against Gram-negative Pseudomonas aeruginosa and they had a MIC value of 62.50 mu g/mL irrespective of the collection area (except the oil from Javinan area). On the contrary, the highest antifungal power against Candida albicans yeast was reached using the essential oil obtained from plants collected in Javinan region (MIC and MBC similar to 62.50 mu g/mL).Conclusions: Overall results underline the influence of environmental conditions of the different areas of Kashan region, on the chemical composition of and antimicrobial activity of the essential oils of Rosa x damascena. In addition, results disclosed that Kamoo seemed to be the most suitable area for the competitive cultivation of R. x damascena to the intensive production of aromatic flower oil and natural antimicrobial essential oils
Extraction of essential oil from Dracocephalum kotschyi Boiss. (Lamiaceae), identification of two active compounds and evaluation of the antimicrobial properties
Full text linkEthnopharmacological relevance: Dracocephalum kotschyi is a medicinal plant widely used in traditional medicine to treat pain, fever, inflammation, and seizures. Aim of the study: Due to the importance of this plant and the well-known antibacterial activity of essential oils, the aim of the present study was to investigate the composition of essential oil and evaluate the antimicrobial activity of its main active compounds. Materials and methods: In order to test its possible application at industrial level the oil was extract from the cultivated and wild plants. The epigean parts were collected in June 2018 from the same region of Daran (Isfahan, Iran). The extraction of essential oil was carried out using a Clevenger apparatus. The composition of the essential oil was assayed by using a gas chromatography/mass spectroscopy apparatus (GC/MS). Results: Results showed that the predominant compounds of essential oil of cultivated plants were α-pinene (13.66%), (E)-citral (12.89%), neral (11.25%), methyl geranate (8.66%), limonene (8.33%), campholenal (6.22%) and geraniol (5.69%), while those found in naturally grown plants were two main compounds: cyclohexylallene (52.63%) and limonene (35.88%). The antimicrobial properties of the plant were determined against 12 strains of microorganism by evaluating inhibition halo, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The highest inhibition halo for both oils from cultivated and wild plants was obtained against Aspergillus brasiliensis. The MIC value against Gram-positive Bacillus subtilis was 31.25 μg/ml, it was the lowest value provided by the essential oil obtained from the cultivated sample, the MIC was significantly lower than that obtained by treating the same strain with Rifampin. On the other hand, Candida albicans had the highest sensitivity (MIC value of 31.25 μg/ml) for the essential oil obtained from wild plants as the inhibitory concentration was lower than that obtained treating the yeast with Nystatin. Conclusions: Therefore, according to the results of the present study, the use of the essential oil obtained from D. kotschyi can be used to protect food and to treat microbial infections
Evaluation of the composition and antimicrobial activities of essential oils from four species of Lamiaceae Martinov native to Iran
Full text linkIn this study the essential oils obtained from four different plant species belonging to the Lamiaceae family were extracted by means of hydrodistillation and their composition and antimicrobial activity were evaluated. About 66 components were identified by using gas chromatography-mass spectrometry (GC–MS), and among all, thymol (67.7%), oleic acid (0.5–62.1%), (−)-caryophyllene oxide (0.4–24.8%), α-pinene (1.1–19.4%), 1,8-cineole (0.2–15.4%), palmitic acid (0.32–13.28%), ( +)spathulenol (11.16%), and germacrene D (0.3–10.3%) were the most abundant in all the species tested (i.e. Thymus daenensis, Nepeta sessilifolia, Hymenocrater incanus, and Stachys inflata). In particular, only the composition of essential oils from H. incanus was completely detected (99.13%), while that of the others was only partially detected. Oxygenated monoterpenes (75.57%) were the main compounds of essential oil from T. daenensis; sesquiterpenes hydrocarbons (26.88%) were the most abundant in S. inflata; oxygenated sesquiterpenes (41.22%) were mainly detected in H. incanus essential oil, while the essential oil from N. sessilifolia was mainly composed of non-terpene and fatty acids (77.18%). Due to their slightly different composition, also the antibacterial activity was affected by the essential oil tested. Indeed, the highest antibacterial and antifungal activities were obtained with the essential oil from T. daenensis by means of the inhibition halo (39 ± 1 and 25 ± 0 mm) against Gram-positive strains such as Staphylococcus aureus and Aspergillus brasiliensis. The minimal inhibitory concentration (MIC) and minimal bactericidal/fungicidal concentration (MBC/MFC) of the essential oils obtained from the four species varied from 16 to 2000 μg/mL and were strictly affected by the type of microorganism tested. As an example, the essential oils from H. incanus and S. inflata were the most effective against the Gram-negative bacterium Pseudomonas aeruginosa (MIC 16 and 63 μg/ml, respectively), which is considered one of the most resistant bacterial strain. Therefore, the essential oils obtained from the four species contained a suitable phytocomplexes with potential applications in different commercial area such as agriculture, food, pharmaceutical and cosmetic industries. Moreover, these essential oils can be considered a valuable natural alternative to some synthetic antibiotics, thanks to their ability to control the growth of different bacteria and fungi
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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