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Essential oil composition and antimicrobial activity of wild and cultivated mint timija (Mentha suaveolens subsp. timija (Briq.) Harley), an endemic and threatened medicinal species in Morocco
No full textThe hydro-distilled essential oils obtained from aerial parts of the wild (w) and cultivated (c) mint timija (Mentha suaveolens subsp. timija), an endemic medicinal species of Morocco, have been analyzed by GC–MS and screened for antimicrobial activity. In total, 35 compounds representing more than 98% of the oils were identified. Menthone (39.4(w)–10.8(c)%), pulegone (62.3(c)–34.3(w)%) and isomenthone (9.3(c)–7.8(w)%) were found as the main components for the two oils. The volatiles of the wild and cultivated material differed significantly in both the percentage of the main components and antimicrobial effect. Pulegone was more dominant in cultivated mint timija (62.3%) than in wild one (34.3%), while menthone was more abundant in the wild material (39.4%). In the antimicrobial assays, both oils displayed good to excellent activity against all microorganisms tested with the oil of the cultivated form being more active
Chemical Characterization and Biological Activities of Essential Oil Obtained from Mint Timija Cultivated under Mineral and Biological Fertilizers
Full text linkCultivation of mint timija (Mentha suaveolens subsp. timija (Briq.) Harley) constitutes a promising solution to the conservation and sustainable utilization of this Moroccan endemic and threatened species. Optimized agronomic practices require mineral and/or biological fertilizer applications. The aim of this study was to determine the effects of application of a complete (N, P, and K) mineral fertilizer and vesicular arbuscular mycorrhizae (VAM) inoculation on the composition, antioxidant, and insecticidal properties of mint timija essential oils (EOs). The GC-MS analyses identified 27 components representing more than 99.9% of the total oils. Menthone (40.7–49.3%), pulegone (31.3–36.5%), and isomenthone (2.5–4.4%) were found to be the main constituents. Cultivation of mint timija with mineral fertilizer and VAM inoculation induced an increase in menthone content and a parallel decrease of pulegone. Both treatments enhanced the antioxidant activity of the investigated EOs in all assays (IC50 ranged from 2.34 ± 0.03 mg/mL to 6.82 ± 0.25 mg/mL), while no significant difference in the toxicities of these oils against Tribolium confusum du Val. has been observed. Overall, we conclude that cultivation using complete mineral fertilizer and VAM inoculation could be useful in modulating the chemical composition and enhancing the antioxidant activity of the EO of this endemic Moroccan species
Chemical characterization and insecticidal properties of essential oils from different wild populations of Mentha suaveolens subsp. timija (Briq.) Harley from Morocco
No full textThe present study is the first investigation of the volatile-oil variability and insecticidal properties of the endemic Moroccan mint Mentha suaveolens subsp. timija (mint timija). The yield of essential oils (EOs) obtained from different wild mint timija populations ranged from 0.20±0.02 to 1.17±0.25% (v/w). GC/MS Analysis revealed the presence of 44 oil constituents, comprising 97.3-99.9% of the total oil compositions. The main constituents were found to be menthone (1.2-62.6%), pulegone (0.8-26.6%), cis-piperitone epoxide (2.9-25.5%), piperitone (0.3-35.5%), trans-piperitone epoxide (8.1-15.7%), piperitenone (0.2-9.6%), piperitenone oxide (0.5-28.6%), (E)-caryophyllene (1.5-11.0%), germacrene D (1.0-15.7%), isomenthone (0.3-7.7%), and borneol (0.2-7.3%). Hierarchical-cluster analysis allowed the classification of the EOs of the different mint timija populations into four main groups according to the contents of their major components. This variability within the species showed to be linked to the altitude variation of the mint timija growing sites. The results of the insecticidal tests showed that all samples exhibited interesting activity against adults of Tribolium castaneum, but with different degrees. The highest toxicity was observed for the EOs belonging to Group IV, which were rich in menthone and pulegone, with LC50 and LC90 values of 19.0-23.4 and 54.9-58.0 μl/l air in the fumigation assay and LC50 and LC90 values of 0.17-0.18 and 0.40-0.52 μl/cm(2) in the contact assay
Plant growth, mineral nutrition and volatile oil composition of Mentha suaveolens subsp. timija (Briq.) Harley cultivated under salt stress conditions
No full textMentha suaveolens subsp. timija is a strict Moroccan endemic species that is intensively exploited from the wild because of its wide ranging medicinal and culinary properties. This has resulted in the species becoming rare or threatened with risk of extinction in the wild. In order to ensure the conservation and sustainable utilization of this valuable medicinal and aromatic plant, its cultivation has been suggested as a promising solution. However, many uncontrolled factors can affect this cultivation including salinity. Thus, the present work aims to evaluate the effects of saline conditions simulated by different NaCl concentrations (0, 50, 100 and 150 mM) on growth (fresh and dry weights), mineral content, essential oil (EO) quantity and quality of M suaveolens subsp. timija. The experiment was conducted inside a shade house at the experimental garden at the Faculty of Sciences, Semlalia-Marrakech during the growing season (February–May) of the year 2010. The results showed that increasing NaCl levels to 150 mM reduced significantly the fresh and dry biomass production by 47.558% and 69.324%, respectively, in comparison to the control. Application of NaCl induced also an increase in Na+ content, while K+ content and K+/Na+ ratio decreased with increasing salt stress. The EO yield decreased by 38.9% and 50.6% at 100 and 150 mM NaCl, respectively, compared with the control (0.77 ± 0.14%). Pulegone, menthone and isomenthone were found to be the principal components of M suaveolens subsp. timija EO. The relative abundance of menthone in particular was affected by salt stress. Based on the present results, it can be concluded that mint timija is a salt sensitive crop and cannot be cultivated in salt-affected areas
Toxicity of essential oils obtained from <i>Juniperus thurifera</i> var. <i>africana</i> and <i>Mentha suaveolens</i> subsp. <i>timija</i> chemotypes against pre-adult stages of <i>Hyalomma aegyptium</i> tick (Acari: Ixodidae)
No full textThis experiment was undertaken to compare the acaricidal activity of two essential oil chemotypes obtained from Mint Timija (Mentha suaveolens subsp. timija (Briq.) Harley) and Incense Juniper (Juniperus thurifera var. africana Maire) against immature stages of Hyalomma aegyptium ticks. The results showed that both chemotypes obtained from the two species presented interesting acaricidal activity. The pulegone and menthone-rich chemotype of Mint Timija (CM1) presented the highest toxic activity, particularly against eggs (LD50 = 17.931 and LD90 = 36.547 ppm) and larvae (LD50 = 0.03 and LD90 = 2.29 ppm). While the piperitone-rich Mint Timija EO (CM2) presented the weakest activity (LD50 = 51.134 and LD90 = 83.663 ppm for eggs, LD50 = 7.84 and LD90 = 21.03 ppm for larvae). Regarding Incense Juniper, the two chemotypes presented relatively moderate activity, with that of sabinene-rich oil (CJ2) being the most effective against eggs (LD50 = 22.293 and LD90 = 53.112 ppm).</p
Total Phenolic, Total Flavonoid Contents and Biological Activities of Mentha Suaveolens subsp. timija Crude Extracts
Full text linkMentha suaveolens subsp. timija is an aromatic herb with a spearmint flavor that plays an important role in the treatment of a wide range of diseases. It has various biological activities, including serving as a natural source of antioxidants and antibacterial agents. The main objective of the present study was to identify biologically active polyphenols and assess the antioxidant capacity of Mentha suaveolens subsp. timija leaves and stems using various organic solvents (hexane, ethanol, methanol) and distilled water for extraction. The antioxidant activity was determined using the ABTS, DPPH, and Total Antioxidant Capacity (TAC) free radical scavenging methods. Results revealed that the total flavonoid and phenolic content ranged from 0.3 to 14.47 mg QE/g and 0.3 to 10.86 mg QE/g, respectively, and from 1.47 to 35.34 mg GAE/g and 1.43 to 37.1 mg GAE/g for leaves and stems, respectively. The extracts exhibited significant antioxidant activity in ABTS, DPPH, and TAC assays, which increased with higher concentrations of polyphenol extracts (P ≤ 0.05). Furthermore, the plant extracts examined in this study displayed remarkable antibacterial activity, particularly against Gram-positive bacteria, with leaf extracts showing better antibacterial activity than stem extracts
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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