BACKGROUND: The purple pitcher plant, Sarracenia purpurea L., is a widely distributed species in North America with a history of use as both a marketed pain therapy and a traditional medicine in many aboriginal communities. Among the Cree of Eeyou Istchee in northern Quebec, the plant is employed to treat symptoms of diabetes and the leaf extract demonstrates multiple anti-diabetic activities including cytoprotection in an in vitro model of diabetic neuropathy. The current study aimed to further investigate this activity by identifying the plant parts and secondary metabolites that contribute to these cytoprotective effects. METHODS: Ethanolic extracts of S. purpurea leaves and roots were separately administered to PC12 cells exposed to glucose toxicity with subsequent assessment by two cell viability assays. Assay-guided fractionation of the active extract and fractions was then conducted to identify active principles. Using high pressure liquid chromatography together with mass spectrometry, the presence of identified actives in both leaf and root extracts were determined. RESULTS: The leaf extract, but not that of the root, prevented glucose-mediated cell loss in a concentration-dependent manner. Several fractions elicited protective effects, indicative of multiple active metabolites, and, following subfractionation of the polar fraction, hyperoside (quercetin-3-O-galactoside) and morroniside were isolated as active constituents. Phytochemical analysis confirmed the presence of hyperoside in the leaf but not root extract and, although morroniside was detected in both organs, its concentration was seven times higher in the leaf. CONCLUSION: Our results not only support further study into the therapeutic potential and safety of S. purpurea as an alternative and complementary treatment for diabetic complications associated with glucose toxicity but also identify active principles that can be used for purposes of standardization and quality control.
- Proceedings of the National Academy of Sciences of the United States of America
- Published over 4 years ago
Slow changes in underlying state variables can lead to “tipping points,” rapid transitions between alternative states (“regime shifts”) in a wide range of complex systems. Tipping points and regime shifts routinely are documented retrospectively in long time series of observational data. Experimental induction of tipping points and regime shifts is rare, but could lead to new methods for detecting impending tipping points and forestalling regime shifts. By using controlled additions of detrital organic matter (dried, ground arthropod prey), we experimentally induced a shift from aerobic to anaerobic states in a miniature aquatic ecosystem: the self-contained pools that form in leaves of the carnivorous northern pitcher plant, Sarracenia purpurea. In unfed controls, the concentration of dissolved oxygen ([O2]) in all replicates exhibited regular diurnal cycles associated with daytime photosynthesis and nocturnal plant respiration. In low prey-addition treatments, the regular diurnal cycles of [O2] were disrupted, but a regime shift was not detected. In high prey-addition treatments, the variance of the [O2] time series increased until the system tipped from an aerobic to an anaerobic state. In these treatments, replicate [O2] time series predictably crossed a tipping point at ∼45 h as [O2] was decoupled from diurnal cycles of photosynthesis and respiration. Increasing organic-matter loading led to predictable changes in [O2] dynamics, with high loading consistently driving the system past a well-defined tipping point. The Sarracenia microecosystem functions as a tractable experimental system in which to explore the forecasting and management of tipping points and alternative regimes.
Sarraceniaceae is a New World carnivorous plant family comprising three genera: Darlingtonia, Heliamphora, and Sarracenia. The plants occur in nutrient-poor environments and have developed insectivorous capability in order to supplement their nutrient uptake. Sarracenia flava contains the alkaloid coniine, otherwise only found in Conium maculatum, in which its biosynthesis has been studied, and several Aloe species. Its ecological role and biosynthetic origin in S. flava is speculative. The aim of the current research was to investigate the occurrence of coniine in Sarracenia and Darlingtonia and to identify common constituents of both genera, unique compounds for individual variants and floral scent chemicals. In this comprehensive metabolic profiling study, we looked for compound patterns that are associated with the taxonomy of Sarracenia species. In total, 57 different Sarracenia and D. californica accessions were used for metabolite content screening by gas chromatography-mass spectrometry. The resulting high-dimensional data were studied using a data mining approach. The two genera are characterized by a large number of metabolites and huge chemical diversity between different species. By applying feature selection for clustering and by integrating new biochemical data with existing phylogenetic data, we were able to demonstrate that the chemical composition of the species can be explained by their known classification. Although transcriptome analysis did not reveal a candidate gene for coniine biosynthesis, the use of a sensitive selected ion monitoring method enabled the detection of coniine in eight Sarracenia species, showing that it is more widespread in this genus than previously believed.
Time-variant species pools shape competitive dynamics and biodiversity-ecosystem function relationships
- Proceedings. Biological sciences / The Royal Society
- Published about 1 year ago
Biodiversity-ecosystem function (BEF) experiments routinely employ common garden designs, drawing samples from a local biota. The communities from which taxa are sampled may not, however, be at equilibrium. To test for temporal changes in BEF relationships, I assembled the pools of aquatic bacterial strains isolated at different time points from leaves on the pitcher plant Darlingtonia californica in order to evaluate the strength, direction and drivers of the BEF relationship across a natural host-associated successional gradient. I constructed experimental communities using bacterial isolates from each time point and measured their respiration rates and competitive interactions. Communities assembled from mid-successional species pools showed the strongest positive relationships between community richness and respiration rates, driven primarily by linear additivity among isolates. Diffuse competition was common among all communities but greatest within mid-successional isolates. These results demonstrate the dependence of the BEF relationship on the temporal dynamics of the local species pool, implying that ecosystems may respond differently to the addition or removal of taxa at different points in time during succession.
Carnivorous pitcher plants employ a variety of putative adaptations for prey attraction and capture. One example is the peculiar forked “fishtail appendage”, a foliar structure widely presumed to function as a prey attractant on adult leaves of Darlingtonia californica (Sarraceniaceae). This study tests the prediction that the presence of the appendage facilitates prey capture and can be considered an example of an adaptation to the carnivorous syndrome.
Abstract Classic niche theory predicts that competing species will evolve to use different resources and interact less, whereas recent niche-converge ideas predict that species evolve to use similar resources and interact more. Most data supporting niche evolution are based on observations of contemporary niche use, whereas experimental support is quite sparse. We followed the evolution of four species of Protozoa during succession in the water-filled leaves of the pitcher plant, Sarracenia purpurea, and found that evolution in multispecies systems follows a surprising pattern. Over several hundred generations, weak competitors evolved to be stronger, while strong competitors evolved to become weaker, which does not conform to expectations of either niche divergence or convergence. Evolution in this system appears to occur in response to characteristics of a suite of several competitors in the community, rather than pairwise interactions. Ecologists may need to rethink the roles of competition and evolution in structuring communities.
From the leaves of Sarracenia purpurea, collected in Mistissini, Quebec, Canada, four goodyerosides and three phenolics and nine known compounds, were isolated. The structures of the compounds were determined by mass spectrometry, including HRMS, and by 1D and 2D NMR spectroscopy.