Over the years 1981 to 2001 there has been a rapid evolution of research into medicinal plants. The major improvement has
been the introduction of simple and predictive bioassays for bioactivity-guided isolation. Radical developments in separation
methods have also taken place. Another important addition has been the development of hyphenated techniques involving HPLC:
LC/UV, LC/MS, LC/MSn and LC/NMR. These are indispensable nowadays for the early detection and identification of new compounds in crude plant extracts.
Hyphenated techniques allow an efficient targeted isolation approach for the discovery of new lead compounds. Other areas
of increasing importance include the investigation of toxic constituents of plants and phytomedicines, and the effects of
genetic modifications on plant secondary metabolites.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
Aristolochia gorgona is described from the Atlantic watershed of Costa Rica and central and eastern Panama. It is similar toA. grandiflora Sw., with which it has been confused in the past. The extensive reported synonymy ofA. grandiflora is reviewed and compared with the new entity. Some new terms are proposed for better describing floral structure in this
species complex, and suggestions are made for its collection and study.Aristolochia gorgona is one of the largest-flowered plant species (in terms of perianth area) in the Neotropics.
Resumen
Aristolochia gorgona se describe de la vertiente Atlántica de Costa Rica y del centro y este de Panamá. Es similar aA. grandiflora Sw., con la cual se ha confundido en el pasado. La extensa sinonimia reportada paraA. grandiflora es revisada, y comparada con la nueva entidad. Se proponen algunos términos nuevos para describir mejor la estructura floral
en éste complejo de especies, y se ofrecen sugerencias para su recolección y estudio.Aristolochia gorgona es una de las especies vegetales con flores más grandes (en cuanto al área del perianto) en el Neotrópico.
We assessed diel animal habitat use in three shallow ponds, using unbaited funnel traps, a large column sampler, and sweep net collections in the upper stratum (0–0.3 m) of littoral and open habitats. In all three ponds, more animals were caught at night than during the day, indicating that use of near-surface waters was greatest at night, particularly in the fishless ponds. All methods yielded similar patterns. Our results demonstrate that nocturnal observations of pond animals are necessary to describe their ecology, even in fishless ponds where diel differences in habitat use or behavior might not be anticipated. 相似文献
Microwave ovens can be used in laboratories for the rapid heating of material – either to dry them completely or to subject a workpiece to sudden thermal stress or electric field stress. Determinations of the moisture content levels in soil or leaf tissue samples, for example, can be made within tens of seconds rather than hours. It is often assumed that placing a load within a microwave oven will result in it being heated evenly as well as quickly, but this is not always the case. This paper describes how a microwave oven works and illustrates how the heating effect within a workpiece can vary. The size and shape of a sample as well as its physical properties determine the power absorption. Equal volumes of water in different shaped containers attain different final temperatures and a tall, cylindrical water load is shown to have different temperatures at different levels. Most microwave ovens do not have a true, variable power capability, but rely on an on/off timing ratio to vary mean power. If this is not appreciated, then erroneous conclusions might be drawn from a set of experiments involving different power levels. Changes in mains supply voltage can affect the amount of energy dissipated in a load. This may introduce variations in results if experiments are conducted over a period of several hours. Experiments are described which illustrate these effects and some criteria and working practices are suggested to improve the consistency and reliability of results when using a microwave oven as a research tool. 相似文献
Introduction: Currently, the diagnosis of psychiatric illnesses is based upon DSM-5 criteria. Although endophenotype-specificity for a particular disorder is discussed, the identification of objective biomarkers is ongoing for aiding diagnosis, prognosis, or clinical response to treatment. We need to improve the understanding of the biological abnormalities in psychiatric illnesses across conventional diagnostic boundaries. The present review investigates the innovative post-genomic knowledge used for psychiatric illness diagnostics and treatment response, with a particular focus on proteomics.
Areas covered: This review underlines the contribution that psychiatric innovative biomarkers have reached in relation to diagnosis and theragnosis of psychiatric illnesses. Furthermore, it encompasses a reliable representation of their involvement in disease through proteomics, metabolomics/pharmacometabolomics and lipidomics techniques, including the possible role that gut microbiota and CYP2D6 polimorphisms may play in psychiatric illnesses.
Expert opinion: Etiologic heterogeneity, variable expressivity, and epigenetics may impact clinical manifestations, making it difficult for a single measurement to be pathognomonic for multifaceted psychiatric disorders. Academic, industry, or government’s partnerships may successfully identify and validate new biomarkers so that unfailing clinical tests can be developed. Proteomics, metabolomics, and lipidomics techniques are considered to be helpful tools beyond neuroimaging and neuropsychology for the phenotypic characterization of brain diseases. 相似文献
Lichen secondary metabolites (LSMs) are regarded with interest for valuable biological properties, but chemical variability among/within lichen taxa has been only fragmentarily characterized by advanced analytical techniques. Knowledge of variability at a local geographic scale has been particularly neglected, while it should address the collection of chemically homogeneous materials to test and exploit LSMs. Here we evaluated the chemical variability of 48 Xanthoparmelia specimens from two rock outcrops in Western Italian Alps, representative of nine morphotypes and sixteen rDNA ITS haplotypes. Qualitative and quantitative analyses were performed by HPLC‐DAD‐ESI‐MS2 and UPLC‐HDR‐DAD, respectively, and revealed the occurrence of 18 LSMs. Chemical partition allowed distinguishing six chemical groups, only partially overlapping with distinct morphotypes and three divergent haplotype groups, which, overall, accounted for the co‐occurrence of different taxa only in part identifiable with species described for Europe. Some morphotypes were variable in presence and concentration of LSMs, and chemical divergences also characterized single ITS haplotypes. Accordingly, the collection of chemically homogeneous materials, even at a local scale, may be not properly addressed by morphological features and ITS barcoding, and should be confirmed by a specimen‐level chemical characterization. 相似文献
Medicago sativa L. (lucerne or alfalfa) is a species which is generally regarded as a cheap source of valuable protein not only for animal fodder but also for nourishment provided in the poorest and developing countries. Moreover, this plant has a long tradition of use in folk medicine. Numerous studies indicate that besides protein, M. sativa synthesizes a variety of secondary metabolites. Among secondary metabolite classes produced by alfalfa, the saponins and flavonoids are of most interest and well characterized. In the current review, we have summarized their chemical structure and method of identification. The potential of alfalfa extracts in medicine and pharmacology has been highlighted. Furthermore, new ways of utilizing flavonoids as well as saponins in agriculture and horticulture are discussed. Collected data can be the starting point and inspiration for scientists of various specialties for future research on this plant. This review draws attention to the necessity of developing modern analytical tools for identification and quantification of individual M. sativa phytochemicals. 相似文献