1,721,007 research outputs found
Chemistry and biological activity of azoprenylated secondary metabolites
No full textN-Prenyl secondary metabolites (isopentenylazo-, geranylazo-, farnesylazo- and their biosynthetic derivatives) represent a family of extremely rare natural products. Only in recent years have these alkaloids been recognized as interesting and valuable biologically active secondary metabolites. To date about 35 alkaloids have been isolated from plants mainly belonging to the Rutaceae family, and from fungi, bacteria, and/or obtained by chemical synthesis. These metabolites comprise anthranilic acid derivatives, diazepinones, and indole, and xanthine alkaloids. Many of the isolated prenylazo secondary metabolites and their semisynthetic derivatives are shown to exert valuable in vitro and in vivo anti-cancer, anti-inflammatory, anti-bacterial, anti-viral, and anti-fungal effects. The aim of this comprehensive review is to examine the different types of prenylazo natural products from a chemical, phytochemical and biological perspective
Composition and antimicrobial activity of the essential oil of Artemisia dracunculus Piemontese from Italy
No full textComposition and antifungal activity of two essential oils of Hyssop (Hissopus officinalis L.)
No full textComposizione fitochimica e attività antimicrobica dell’olio essenziale di Artemisia dracunculus L. var. “PIEMONTESE”.
No full textChemical composition and inhibitory activity against Helicobacter pylori of the essential oil of Apium nodiflorum (Apiaceaae).
No full text“Chemistry and pharmacology of secondary oxyprenylated plant metabolites”
No full textOxyprenylated natural products (isopentenyloxy-, geranyloxy- and the less spread farnesyloxy- compounds and their biosynthetic derivatives) represent a family of secondary metabolites that have been considered for years just as biosynthetic intermediates of C-prenylated derivatives. Only in the last decade these natural products have been recognized as interesting and valuable biologically active phytochemicals. Up to now about 300 molecules have been isolated from plants mainly belonging to the families of Rutaceae and Compositae, comprising common edible vegetables and fruits. A wide variety of compounds containing a prenyloxy side chain have been isolated and these comprise alkaloids, coumarins, flavonoids, cinnamic acids, benzoic acids, phenols, alcohols, aldehydes, anthraquinones, chalcones, lignans, xanthones, aceto- and benzophenones and other more uncommon skeletons. Many of the isolated oxyprenylated natural products and their semisynthetic derivatives were shown to exert in vitro and in vivo remarkable anti-cancer, anti-inflammatory, anti-microbial and anti-fungal effects. The aim of this review is to examine in detail the different types of oxyprenylated natural compounds from a phytochemical and pharmacological point of view
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
Effects of phytoplasma presence on the chemical composition of essential oils from Grindelia robusta Nutt., Echinacea purpurea Moench., and Monarda fistulosa L.
No full textPlants are well recognized to change the secondary metabolites pattern of biosynthetic pathways in response to virus, bacteria, phytoplasma or fungi infections, and/or attacks by phytophagous insects. Most of these secondary metabolites are represented by volatile semiochemicals used as chemical defence in the sense of repellency. Such changes in the phytochemical profile greatly affect the quality and the commercial value of plants used for medicinal and cosmetic purposes. As a continuation of our studies aimed to verify the effect of phytoplasma infections on the volatile chemicals production, we report the differences detected between healthy and infected plants of Grindelia robusta Nutt. (Asteraceae), Echinacea purpurea Moench. (Asteraceae), and Monarda fistulosa L. (Lamiaceae), all species of great importance in the medicinal practice and grown at the Herb Garden of Casola Valsenio (Ravenna, Emilia Romagna region, northern Italy). Before flowering, only a few yellow symptoms were present on the leaves; however in some cases, the plants showed reduction of leaf size and stunting; whereas, at blooming, severe virescence and phyllody symptoms were observed. Samples from symptomatic plants were collected and tested for phytoplasma presence. Nested PCR/RFLP analyses on 16Sr DNA gene confirmed that in all the symptomatic samples examined phytoplasmas identified belonged to ribosomal subgroup 16SrI-B (Aster yellows: AY, ‘Candidatus Phytoplasma asteris’) in the case of G. robusta and E. purpurea, and to ribosomal soubgroup 16SrXII-A stolbur, for M. fistulosa. These two phytoplasmas are associated with a number of economically important diseases worldwide and recent reports indicated the presence of stolbur phytoplasmas in hyssop (Hyssopus officinalis) and in Parietaria spp., and of AY in woolly foxglove (Digitalis lanata).
Essential oils were obtained from aerial parts of healthy and phytoplasma-infected plants by hydrodistillation followed by GC/MS analysis using a reported procedure. In all cases, significant differences in the chemical composition of essential oils were observed. In G. robusta infected plants, a higher percentage of limonene, borneol (both almost > 50%), and borneol acetate (15% in healthy plants and 21.3% in infected ones) were detected. Essential oil of E. purpurea revealed differences for limonene (2.2% in healthy plants and 4.4% in infected ones), cis-verbenol (1.8% and 5.6% respectively), verbenone (2.7% and 11.4%), and to a lesser extent carvone (0.8% to 2.5%). Infection by phytoplasmas belonging to ribosomal soubgroup 16SrXII-A stolbur in M. fistulosa led to an increase of monoterpene hydrocarbons such as -thujene, -pinene, 3-carene, and myrcene and to a decrease in aromatic monoterpene like p-cymene and thymol. Phytoplasmas have an appreciable influence in the content of secondary metabolites and these three species increase the concentration of the above cited monotherpens as chemical response to the presence of these pathogens
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