1,721,120 research outputs found
GC-MS and SPME-GC/MS analysis and bioactive potential evaluation of essential oils from two viola species belonging to the V. calcarata complex
No full textViola calcarata L. and Viola dubyana Burnat ex Gremli belong to the V. calcarata complex in Viola section Melanium (Violaceae family). For the first time, the essential oils (EOS) obtained by hydrodistillation from dried flowers, were analyzed by GC/MS and SPME-GC/MS to describe their volatile chemical profile. Differences in the qualitative and quantitative composition between the two violets have been found. A total of 43 compounds were identified among which methyl salicylate was the most abundant (from 45.5 to 68.0%) both in the vapor and liquid phase. The performed bioactivity tests pointed out the greater effect of V. dubyana EO compared to that obtained from V. calcarata. Nevertheless, both EOs proved to be good scavengers, especially toward the ABTS⋅+ radical. They also showed a dose-dependent phytotoxic action against Sinapis alba and Lolium multiflorum. Their seed germination was inhibited up to 100% and 25%, respectively, in response to the highest used dose (100 μL) of each EO. Furthermore, a significant decrease in root and shoot length was observed. The resulting seedling vigor index was reduced by 15–100% and 8–82% for S. alba and by 11–91% and 4–91% for L. multiflorum by V. dubyana and V. calcarata EOS, respectively
Plant Products for Innovative Biomaterials in Dentistry
No full textDental biomaterials and natural products represent two of the main growing
research fields, revealing plant-derived compounds may play a role not only as
nutraceuticals in affecting oral health, but also in improving physico-chemical properties of
biomaterials used in dentistry. Therefore, our aim was to collect all available data concerning
the utilization of plant polysaccharides, proteins and extracts rich in bioactive phytochemicals
in enhancing performance of dental biomaterials. Although compelling evidences are
suggestive of a great potential of plant products in promoting material-tissue/cell interface,
to date, only few authors have investigated their use in development of innovative dental
biomaterials. A small number of studies have reported plant extract-based titanium implant
coatings and periodontal regenerative materials. To the best of our knowledge, this review
is the first to deal with this topic, highlighting a general lack of research findings in an
interesting field which still needs to be investigate
Uromyces appendiculatus Infection in BTH-Treated Bean Plants: Ultrastructural Details of a Lost Fight
No full textThe mechanisms of BTH [benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester]-induced resistance against bean rust caused by Uromyces appendiculatus have been explored in Phaseolus vulgaris by light and transmission electron microscopy, following the infection progression in plants challenged 7 days after treatment. While BTH did not affect uredospore germination and fungal penetration in the substomatal cavity, a first impairment to the colonization appeared evident about 48-96 h after inoculation, with alterations of infection hypha structure and reduction in mycelium expansion. No differences were found in this phase regarding the formation and ultrastructure of haustoria in untreated and BTH-treated plants, except for the deposition of electron-opaque material in the extrahaustorial matrix of the latter. A second and decisive impairment in fungal progression was observed at 7-10 days after inoculation when host cell penetrated, or in close contact with the fungal hyphae, were impregnated by phenolic compounds. The same was observed in fungal walls, particularly around haustoria, thus hampering the biotrophic habitus of the fungus and further mycelium spreading. This, in turn, prevented the evasion of fungal reproductive structures, the uredinia, and the appearance of visible symptoms. No particular ultrastructural alterations were observed in most of the penetrated cells, even at late stages of infection, indicating that BTH treatment does not induce host cells to respond with a hypersensitive reaction (HR). A parallel time course of the expression of phenylalanine ammonia lyase (PAL) gene, the key enzyme for the synthesis of phenylpropanoidic phytoalexins and many other phenolics, has shown that PAL mRNA is strongly and persistently transcripted in BTH-treated plants since the 6th h after treatment, though no apparent ultrastructural alterations were detectable up to some days after pathogen challenging. This indicates that BTH, at the employed concentration of 0.3 mM, directly activates the plant's own defences, thus accounting for the observed full protection against bean rust
Chemical volatile composition and phytotoxic potential of Daphne gnidium L. leaves
No full textDaphne gnidium L. (Thymelaeaceae) is an evergreen shrub from the Mediterranean area traditionally used for its medicinal and non-medicinal properties. Several studies showed its adverse impact on different targets including malignant cells, microbes, radicals, insects. The negative interactions between D. gnidium and other plant species have been rather neglected so far, as well as its chemical volatile composition. Therefore, this work aimed to assess the phytotoxic activity of D. gnidium on filter paper and soil in pre-emergence conditions by testing both the aqueous extract (10–100%) and the powder (0.25–1 g) obtained from the leaves as bioagrochemicals. The results showed that D. gnidium was able to significantly decrease seed germination and growth parameters of the receiver plants with different effectiveness (p-values < 0.05). Overall, Sinapis alba L. (Brassicaceae) was the most susceptible species followed by Lolium multiflorum Lam. (Poaceae) and Trifolium incarnatum L. (Fabaceae) while aqueous extract was more active than the powder. Solid-Phase Microextraction (SPME) sampling technique and Gas Chromatograph/Mass spectrometer (GC/MS) analyses were used to characterize the volatile fraction highlighting considerable differences in the composition of the analyzed samples. Hexahydrofarnesyl acetone (29.7%) followed by 3,7,11,15-tetramethyl-2-hexadecen-1-ol (28.3%) and β-damascenone (32.0%) followed by eudesma-1,4(15), 11-triene (27.1%) were detected as main volatile compounds of the powder and the aqueous extract, respectively
Acute exposure of the aquatic macrophyte Callitriche obtusangula to the herbicide oxadiazon: The protective role of N-acetylcysteine
No full textIn this study we investigated the acute exposure of the aquatic macrophyte Callitriche obtusangula to the herbicide oxadiazon (Ronstar®). The toxic effects on C. obtusangula were evaluated, 24 h after exposure, by assessing visible necrotic leaf lesions and, 12 h after exposure, via analyses of dead cells and hydrogen peroxide (H2O2) deposits localized by histocytochemical analysis with Trypan blue and 3,3′-diaminobenzidine (DAB), respectively. As a result, we found that 0.1275 μg L-1 a.i. (active ingredient) oxadiazon was the maximum concentration that produced no observable adverse effects (NOAEC) both at leaf and tissue levels, at any considered exposure time. Additionally, we assayed the protective effect of pre-treatment with 0.25 mM N-acetylcysteine (NAC), a cysteine donor, on the damage caused by the toxic herbicidal dose of 6.37 μg L-1 a.i to C. obtusangula, correlating the NAC observed protection to the direct H2O2-scavenging and to the enhancement of glutathione parameters. NAC-treated plants showed a fourfold increase in the GSH (reduced glutathione) + GSSG (oxidised glutathione) content (149.2 nmol g-1 FW) compared to controls (36.1 nmol g-1 FW); in the NAC + oxadiazon treatments, the GSH + GSSG content was more than fivefold higher (202.1 nmol g-1 FW). GSH showed a similar trend in NAC and NAC + oxadiazon treatments, being six- (130.0 nmol g-1 FW) and eightfold (185.0 nmol g-1 FW) higher, respectively, compared to controls (20.7 nmol g-1 FW). Accordingly, the GSH/GSSG ratio in NAC- and NAC + oxadiazon-treated plants was significantly increased compared to controls, indicating alleviation of oxidative stress. © 2008 Elsevier Ltd. All rights reserved
Soil application of effective microorganisms (EM) maintains leaf photosynthetic efficiency, increases seed yield and quality traits of bean (Phaseolus vulgaris L.) plants grown on different substrates
No full textEM (effective microorganisms) is a biofertilizer consisting of a mixed culture of potentially beneficial microorganisms. In this study, we investigated the effects of EM treatment on leaf in vivo chlorophyll a fluorescence of photosystem II (PSII), yield, and macronutrient content of bean plants grown on different substrates (nutrient rich substrate vs. nutrient poor sandy soil) in controlled environmental conditions (pot experiment in greenhouse). EM-treated plants maintained optimum leaf photosynthetic efficiency two weeks longer than the control plants, and increased yield independent of substrate. The levels of seed nutritionally-relevant molecules (proteins, lipids, and starch) were only slightly modified, apart from the protein content, which increased in plants grown in sandy soil. Although EM can be considered a promising and environmentally friendly technology for sustainable agriculture, more studies are needed to elucidate the mechanism(s) of action of EM, as well as its efficacy under open field conditions
A comparative study of the chemical composition by spme-gc/ms and antiradical activity of less common citrus species
No full textCitrus secondary metabolites, such as terpene compounds, are very important for human health due to their bioactivity including anti-inflammatory, anti-cancer, and antioxidant effects. In this work, for the first time, the volatile chemical composition of peels and juices from four different Citrus species (C. junos, Citrus × aurantium, C. aurantium ‘Bizzarria’ and C. medica ‘Florentina’, commonly known as Yuzu jeune, Oni Yuzu, Bizzarria orange and Florence cedar, respectively) was investigated by Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique and the antiradical activity was also examined. The results showed that limonene and γ-terpinene were the main volatile substances detected both in the juices and in the peels, followed by other minority compounds responsible for the phyto-complex of the unique aromas which characterize each individual analyzed Citrus species. Principal component analysis (PCA), performed on volatile compounds, showed both some correlation as well as a clear separation between the juice and the peel of each species. Among them, Oni Yuzu juice was found to be the richest in total polyphenols and flavonoids while its capacity to scavenge ABTS•+ and DPPH• radicals was similar to that of Yuzu Jeune and Bizzarria orange
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
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