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Plant Metabolites (plant + metabolite)
Selected AbstractsChemically-mediated host-plant location and selection by root-feeding insectsPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2006Scott N. Johnson Abstract., Recent studies have shown that root-feeding insects can be of considerable importance in terms of agricultural damage, their indirect impacts on above-ground herbivores and their efficacy as biocontrol agents of weeds. To date, isolated studies have made it difficult to identify the mechanisms by which soil-dwelling insects locate and select host-plant roots. This review synthesizes 78 studies describing root location and selection. Soil insect herbivores do not rely on encountering roots at random, but orientate towards them using semiochemicals that enable specialist insects to distinguish host-plants from unsuitable plants. Secondary plant metabolites released into the rhizosphere (alcohols, esters and aldehydes representing 37% of reported examples) underpin host-plant location and recognition, with 80% having ,attractant' properties. Insects feeding on a limited range of plants tend to exploit host-specific secondary metabolites, whereas nonspecialist feeders appear to use more general semiochemicals. When insects reach the roots, contact chemosensory cues act as either ,phagostimulants' (48% of the compounds being sugars) or feeding ,deterrents' (notably phenolic compounds). Twenty studies conclude that CO2 is the major primary plant metabolite that allows insects to locate to roots. However, several features of CO2 emissions from roots mitigate against it as a precise location cue. In addition to its lack of specificity, gradients of root emitted CO2 do not persist for long periods and vertical gradients of CO2 in the soil tend to be stronger than horizontal gradients. A conceptual model is presented, emphasizing the importance of soil properties (e.g. porosity, moisture) on chemical diffusion and insect motility. [source] Capillary electrophoresis-mass spectrometry characterisation of secondary metabolites from the antihyperglycaemic plant Genista teneraELECTROPHORESIS, Issue 11 2006Emma L. Edwards Abstract Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100,min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant's secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G.,tenera. Twenty-six different components are distinguished in an analysis time of only 10,min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting. [source] Root herbivores and detritivores shape above-ground multitrophic assemblage through plant-mediated effectsJOURNAL OF ANIMAL ECOLOGY, Issue 4 2010Adela González Megías Summary 1.,Indirect effects mediated by changes in plant traits are the main mechanism by which above- and below-ground herbivores affect each other and their enemies. Only recently the role of decomposers in the regulation of such plant-based systems has been considered. We hypothesized that: (i) below-ground organisms, both herbivores (negative effect on plants) and detritivores (positive effect on plants), will have a profound effect on the interactions among above-ground arthropods; (ii) floral herbivores will negatively affect other above-ground herbivores associated with the plant; and (iii) not only above- and below-ground herbivores, but also detritivores will affect the production of secondary metabolites, i.e. glucosinolates, in the plants. 2.,We manipulated the presence of above-ground herbivores, below-ground herbivores and below-ground detritivores on the Brassicaceae Moricandia moricandioides in the field to disentangle their individual and combined effects on other organism groups. We also investigated their effects on the plant's chemical defence to evaluate potential mechanisms. 3.,Our results show that not only above- and below-ground herbivores, but also detritivores affected other herbivores and parasitoids associated with the host plant. Most effects were not additive because their strength changed when other organisms belonging to different functional groups or food web compartments were present. Moreover, below-ground herbivore and detritivore effects on above-ground fauna were related to changes in glucosinolate concentrations and in quantity of resources. 4.,This study indicates that multitrophic interactions in plant-based food webs can dramatically change by the action of below-ground organisms. One of the most important and novel results is that detritivores induced changes in plant metabolites, modifying the quality and attractiveness of plants to herbivores and parasitoids under field conditions. [source] Antimalarial compounds isolated from plants used in traditional medicineJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 11 2009Joanne Bero Abstract Objectives This review covers the compounds with antiplasmodial activity isolated from plants published from 2005 to the end of 2008, organized according to their phytochemical classes. Details are given for substances with IC50 values , 11 ,M. Key findings Malaria is a major parasitic disease in many tropical and subtropical regions and is responsible for more than 1 million deaths each year in Africa. The rapid spread of resistance encourages the search for new active compounds. Nature and particularly plants used in traditional medicine are a potential source of new antimalarial drugs as they contain molecules with a great variety of structures and pharmacological activities. Summary A large number of antimalarial compounds with a wide variety of structures have been isolated from plants and can play a role in the development of new antimalarial drugs. Ethnopharmacological approaches appear to be a promising way to find plant metabolites that could be used as templates for designing new derivatives with improved properties. [source] Modulatory effects of Aloe vera leaf gel extract on oxidative stress in rats treated with streptozotocinJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2005S. Rajasekaran Oxidative stress is currently suggested as a mechanism underlying diabetes and diabetic-related complications. Oxidative stress results from an imbalance between radical-generating and radical-scavenging systems. Many secondary plant metabolites have been reported to possess antioxidant activity. This study was designed to evaluate the potential antioxidative activity of the ethanolic extract from Aloe vera leaf gel in the plasma and pancreas of streptozotocin (STZ)-induced diabetic rats. Glibenclamide was used as a standard reference drug. Oral administration of ethanolic extract at a concentration of 300 mg kg,1 body weight for 21 days resulted in a significant reduction in fasting blood glucose, thiobarbituric acid reactive substances, hydroperoxides and alpha-tocopherol and significant improvement in ascorbic acid, reduced glutathione and insulin in the plasma of diabetic rats. Similarly, the treatment also resulted in a significant reduction in thiobarbituric acid reactive substances, hydroperoxides, superoxide dismutase, catalase and glutathione peroxidase and significant improvement in reduced glutathione in the pancreas of STZ-induced diabetic rats when compared with untreated diabetic rats. The ethanolic extract appeared to be more effective than glibenclamide in controlling oxidative stress. Thus, this study confirms the ethnopharmacological use of Aloe vera in ameliorating the oxidative stress found in diabetes. [source] Glucose, fructose and sucrose content in broccoli, white cabbage and Portuguese cabbage grown in early and late seasonsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2001Eduardo Rosa Abstract Consumption of Portuguese cabbage and white cabbage is very high in Portugal, but diets including broccoli have been highly recommended owing to recognition of the health-protective effects of secondary plant metabolites. Broccoli production is generally concentrated in the summer/winter season, but the demand for a fresh product throughout the year requires production in other seasons. Sugars might affect flavour and the acceptance of broccoli by consumers. This study reports the free fructose, glucose and sucrose content in primary and secondary inflorescences of 11 cultivars of broccoli, one white cabbage and four Portuguese cabbages grown in early (March,July) and late (August,January) seasons in the northern region of Portugal. On average the results show that the total free sugar content in the broccoli cultivars, except for cv Marathon, is significantly (P,<,0.05) lower than in the other cabbages. Fructose was the major sugar in the three types of Brassica, representing between 48.8 and 56.9% of the total sugar content in broccoli cvs Marathon and Senshi respectively and between 48.7% (cv Mirandela) and 53.8% (cv Murciana) in the other cabbages. Glucose was the second major sugar, while sucrose represented a maximum of 20.5% in broccoli cv Shogun and 11.1% in cv Murciana. The growing season influenced the free sugar content, with generally higher levels in the spring/summer than in the summer/winter season in broccoli, while an opposite tendency was noted in the other Brassica species. In broccoli the sugar levels in the primary inflorescences were generally lower than in the secondary inflorescences, except for sucrose. © 2001 Society of Chemical Industry [source] Chemically-mediated host-plant location and selection by root-feeding insectsPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2006Scott N. Johnson Abstract., Recent studies have shown that root-feeding insects can be of considerable importance in terms of agricultural damage, their indirect impacts on above-ground herbivores and their efficacy as biocontrol agents of weeds. To date, isolated studies have made it difficult to identify the mechanisms by which soil-dwelling insects locate and select host-plant roots. This review synthesizes 78 studies describing root location and selection. Soil insect herbivores do not rely on encountering roots at random, but orientate towards them using semiochemicals that enable specialist insects to distinguish host-plants from unsuitable plants. Secondary plant metabolites released into the rhizosphere (alcohols, esters and aldehydes representing 37% of reported examples) underpin host-plant location and recognition, with 80% having ,attractant' properties. Insects feeding on a limited range of plants tend to exploit host-specific secondary metabolites, whereas nonspecialist feeders appear to use more general semiochemicals. When insects reach the roots, contact chemosensory cues act as either ,phagostimulants' (48% of the compounds being sugars) or feeding ,deterrents' (notably phenolic compounds). Twenty studies conclude that CO2 is the major primary plant metabolite that allows insects to locate to roots. However, several features of CO2 emissions from roots mitigate against it as a precise location cue. In addition to its lack of specificity, gradients of root emitted CO2 do not persist for long periods and vertical gradients of CO2 in the soil tend to be stronger than horizontal gradients. A conceptual model is presented, emphasizing the importance of soil properties (e.g. porosity, moisture) on chemical diffusion and insect motility. [source] Semi-quantitative and structural metabolic phenotyping by direct infusion ion trap mass spectrometry and its application in genetical metabolomicsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2009Albert Koulman The identification of quantitative trait loci (QTL) for plant metabolites requires the quantitation of these metabolites across a large range of progeny. We developed a rapid metabolic profiling method using both untargeted and targeted direct infusion tandem mass spectrometry (DIMSMS) with a linear ion trap mass spectrometer yielding sufficient precision and accuracy for the quantification of a large number of metabolites in a high-throughput environment. The untargeted DIMSMS method uses top-down data-dependent fragmentation yielding MS2 and MS3 spectra. We have developed software tools to assess the structural homogeneity of the MS2 and MS3 spectra hence their utility for phenotyping and genetical metabolomics. In addition we used a targeted DIMS(MS) method for rapid quantitation of specific compounds. This method was compared with targeted LC/MS/MS methods for these compounds. The DIMSMS methods showed sufficient precision and accuracy for QTL discovery. We phenotyped 200 individual Loliumperenne genotypes from a mapping population harvested in two consecutive years. Computational and statistical analyses identified 246 nominal m/z bins with sufficient precision and homogeneity for QTL discovery. Comparison of the data for specific metabolites obtained by DIMSMS with the results from targeted LC/MS/MS analysis showed that quantitation by this metabolic profiling method is reasonably accurate. Of the top 100 MS1 bins, 22 ions gave one or more reproducible QTL across the 2 years. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sex, age, and family differences in the chemical composition of owl monkey (Aotus nancymaae) subcaudal scent secretionsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2008Edith A. MacDonald Abstract Numerous behavioral studies have shown that animals use olfactory cues as inbreeding avoidance or kin avoidance mechanisms, implying that scent is unique to families. However, few studies have analyzed the chemical profile of a scent and ascertained the messages that are conveyed in scent secretions. Owl monkeys (Aotus nancymaae) are socially monogamous primates that utilize scent when interacting with foreign conspecifics. This suggests there is a difference in the chemical composition of scent marks. We chemically analyzed sub-caudal gland samples from three families of captive owl monkeys (Aotus nancymaae). Samples were analyzed by capillary GC-MS and relative retention time and fragment pattern was compared with known standards. Gland samples were high in large plant-based shikikate metabolites and fatty ketones; alcohols, acids, and acetates were virtually absent. Gender, age, and family could be reliably classified using discriminant analysis (92.9, 100, and 100%, respectively). Female scent profiles were greater in concentration of aromatic plant metabolites, possibly the result of a different diet or physiological differences in female metabolism as compared to male. Offspring of adult age still living in their natal group showed a less complex chemical profile than their parents. Finally, each family had its own unique and complex chemical profile. The presence of family scent may play a role in mediating social interactions. Am. J. Primatol. 70:12,18, 2007. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||