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At least 631 records · Page 35Linked to original sources
PubMed2006

Mass spectrometry strategies for venom mapping and peptide sequencing from crude venoms: case applications with single arthropod specimen.

Due to their complexity and diversity, animal venoms represent an extensive source of bioactive compounds such as peptides and proteins. Conventional approaches for their characterization often require large quantities of biological material. Current mass spectrometry (MS) techniques now give access to a wealth of information in a short working time frame with minute amounts of sample. Such MS approaches may now be used for the discovery of novel compounds, and once their structure has been determined they may be synthesized and tested for functional activity. Molecular mass fingerprints of venoms allow the rapid identification of known toxins as well as preliminary structural characterization of new compounds. De novo peptide sequencing by tandem mass spectrometry (MS/MS) offers rapid access to partial or total primary peptide structures. This article, written as a tutorial, also contains new material: molecular mass fingerprint analysis of Orthochirus innesi scorpion venom, and identification of components from bumblebee Bombus lapidarius venom, both collected from one single specimen. The structure of the three major peptides detected in the Bombus venom was fully characterized in one working day by de novo sequencing using an electrospray ionization hybrid quadrupole time-of-flight instrument (ESI-QqTOF) and a matrix-assisted laser desorption ionization time-of-flight instrument (MALDI-LIFT-TOF-TOF). After presenting the MS-based sequence elucidation, perspectives in using MS and MS/MS techniques in toxinology are discussed.

Animals↗
PubMed2004

Nutraceutical/drug/anti-terrorism safety assurance through traceability.

Nutraceuticals are naturally occurring/derived bioactive compounds that are reported to have health benefits. The delivery systems for nutraceuticals are foods (functional foods), supplements, or both. Drugs are designed to have medicinal properties for the prevention and treatment of identified diseases or signs and symptoms of disease. Counterfeit drugs contain either placebo, materials not identified in the labeling or substandard or impure materials, which may produce untoward pharmacological or toxicological effects. In addition, the consumer has the right to microbiological safety and prevention from adverse exposure to hazardous chemical(s), and other adverse compounds. Nutraceutical/drug delivery systems are viewed as approaches to (1) enhanced consumer health, (2) decreased healthcare costs, and (3) enhanced economic development. Therefore, the nutra/pharma/ceutical industry is reliant upon a strong underpinning of diversified research that addresses safety and assures chemical and biological efficacy. Significant safety through traceability can be assured by the coupling of the technologies of (a) global positioning (GPS); (b) bar/chip coding; and (c) hazard analysis critical control point (HACCP) management, coupled to rapid nanotechnology marker assays now under development.

Agriculture↗
PubMed2006

Can plant biochemistry contribute to understanding of invasion ecology?

Ecologists have long searched for an explanation as to why some plant invaders become much more dominant in their naturalized range than in their native range, and, accordingly, several non-exclusive ecological hypotheses have been proposed. Recently, a biochemical explanation was proposed--the "novel weapons hypothesis"--based on findings that Centaurea diffusa and Centaurea maculosa produce bioactive compounds (weapons) that are more active against naïve plant species in the introduced range than against co-evolved species in the native range. In this Opinion article, we revise and expand this biochemical hypothesis and discuss experimental and conceptual advances and limitations.

Adaptation, Physiological↗
PubMed2026

Painting new pathways: Castilleja enters the genomic era.

Castilleja (Orobanchaceae), commonly known as Indian paintbrush, is a genus of approximately 200 hemiparasitic species found primarily across the Americas. Long studied for its taxonomic complexity, vibrant floral displays, and ecological interactions with host plants, Castilleja has recently emerged as a versatile research system spanning parasitic biology, specialized metabolism, conservation genetics, and pharmacology. The availability of whole-genome sequencing is transforming the field, revealing expanded gene families involved in host recognition, enabling genomic species delimitation of cryptic taxa, and providing frameworks for mapping biosynthetic pathways of bioactive compounds, including iridoid glycosides and phenylethanoid glycosides. This review synthesizes advances across these disciplines and highlights how genomics serves as an integrative force connecting taxonomy, ecology, phytochemistry, and parasitic biology in this genus.

Castilleja↗
PubMedDate not supplied

Microiontophoresis electrode location by neurohistological marking: Comparison of four native dyes applied from current balancing electrode channels.

INTRODUCTION: The re-establishment of electrode position after microiontophoresis with multi-barrelled electrodes has always been a complicated and mostly inaccurate procedure. The present report describes a new method for 'on line' neurohistological marking of each recording position during experimental sessions in which in vivo microiontophoresis was combined with extracellular single unit recording. METHODS: We tested the effectiveness of four native dyes: pontamine sky blue (PSB), methylene blue (MB), cresyl violet (CV) and toluidine blue (TB). They were ejected from the continuous balancing channels of multi-barrelled microelectrodes during iontophoresis in place of the usual sodium chloride solution. RESULTS: The present results are based on observations obtained from 66 neuronal recordings and 42 labelled sites in the rat neocortex. Results indicate that none of the tested native dyes altered the spontaneous firing rate of the neurons, nor did they have any influence on the applied bioactive compounds. Recording positions were detected as small, labelled spots in brain slices (2-12 microm in diameter) at the end of the recording tracks. Labelling was successful with MB and PSB, but not with CV or TB. In addition, MB provided good labelling with a low net ejection current. DISCUSSION: The present results suggest that using native dyes, especially MB, instead of sodium chloride in current balancing channels during in vivo microiontophoresis provides fast and accurate confirmation of electrode placement. This method saves the experimenter the time consuming further application of secondary labelling procedures after such experiments. Moreover, the MB-labelling we describe here is focal, enabling a more accurate verification of the site of recording and/or application of various neuroactive compounds. In addition, MB labelled accurately and reliably and with very low ejection currents, presumably due to its smaller molecular weight and higher relative mobility.

Animals↗
PubMed2026

Comparative metabolomic and transcriptomic profiling of flavonoid diversity and antioxidant capacity in three Isatis species.

Flavonoids are key bioactive compounds in plants with significant health benefits. This study employs an integrated multi-omics approach to investigate flavonoid diversity and antioxidant capacity across three Isatis species: I. oblongata, I. tinctoria, and I. indigotica. Metabolomic profiling identified 200 flavonoids, with glycosides being the most abundant class. I. tinctoria exhibited the highest total flavonoid content and antioxidant activity, strongly correlated with the accumulation of 53 core differential flavonoid metabolites, most of which were glycosylated derivatives. Transcriptomic analysis revealed coordinated upregulation of phenylpropanoid pathway genes and specific UDP-glycosyltransferases (UGTs) in I. tinctoria, providing a genetic basis for its enhanced glycoside production. The study establishes a clear genotype-metabolite-phenotype linkage, highlighting glycosylation as a key mechanism underlying flavonoid-driven antioxidant superiority in Isatis. Although the current evidence is primarily correlative, the consistent and strong associations across independent transcriptomic, metabolomic, and antioxidant datasets provide a robust foundation for this conclusion. These findings offer new insights into the metabolic evolution and regulatory networks of flavonoids, with implications for breeding and metabolic engineering of high-value medicinal plants.

Flavonoids↗
PubMed2005

Studying phospholipid metabolism using yeast systematic and chemical genetics.

Most phospholipid metabolic pathways in the budding yeast Saccharomyces cerevisiae are analogous to their mammalian counterparts. The biological tractability of yeast provides for an opportunity to rapidly determine functions of specific lipids or lipid metabolic pathways using both classical and chemical-genetic techniques. The recent generation of the yeast genome deletion collection revealed that approximately 75% of yeast genes are not essential for life. Coupling analysis of the yeast deletion collection with automation using high-throughput robotics enables yeast genetic screens to be more thorough and bypasses the requirement for library screens to identify genes of interest. Two high-throughput yeast genetic methods are described, systematic synthetic lethality and chemical genetics. Systematic synthetic lethality is based on the principle that inactivation of two genes separately has minimal effects on cell growth whereas inactivation of both genes simultaneously results in growth defects due to their shared requirement in a particular cellular process. Chemical genetics is the analysis of bioactive compounds to determine processes that regulate susceptibility to the compound under study, and provides powerful data regarding precise targets and mechanism of action that regulate action of the compound.

Automation↗
PubMed2001

Inhibition of stress-activated protein kinase in the ischemic/reperfused heart: role of magnesium tanshinoate B in preventing apoptosis.

The activation of stress-activated protein (SAP) kinase may lead to an induction of apoptosis that is responsible for part of the cardiomyocyte death in reperfusion injury. The objective of the present study was to investigate the mechanism by which magnesium tanshinoate B (MTB), a bioactive compound isolated from Danshen, prevents apoptosis in cardiomyocytes in the ischemic/reperfused heart. Isolated adult rat hearts were perfused by the Langendorff mode with medium containing MTB prior to the induction of normothermic global ischemia. At the end of the 30-min ischemic period, the heart was reperfused with the same medium with or without MTB for an additional 20 min. In the MTB-treated ischemic/reperfused heart, the number of apoptotic nuclei was reduced by 2.5-fold in comparison to that in untreated ischemic/reperfused controls [23 +/- 4 vs 57 +/- 7 (mean +/- SD) TUNEL-positive cells, respectively, N = 3-4, P < 0.001]. SAP kinase activity was elevated 1.7-fold in ischemic/reperfused rat hearts [35.6 +/- 3.8 vs 21.2 +/- 3.3 (control) (mean +/- SEM) relative densitometric units, N = 4-6, P < 0.05]. Treatment with MTB abolished this elevation in SAP kinase activity (25.0 +/- 5.2 relative densitometric units), which was also decreased by 40% in the nucleus. When the heart was subjected to ischemia alone, there was no significant change in SAP kinase activity in the presence or absence of MTB. MTB did not appear to affect the p38 mitogen-activated protein kinase activity in this model system. In conclusion, MTB was shown to have cardioprotective activity against apoptosis, probably through the inhibition of SAP kinase activity.

Animals↗
PubMed1999

Synthesis of glucosylated 1,2,3-triazole derivatives.

A series of potential bioactive compounds, 1-glucosyl-4-heterocyclyl-5-(p-substituted-phenyl)-1,2,3-triazoles , were synthesized. Highly stereoselective products were obtained in good yield. Primary activity screening showed that this type of N-glucosylic compound possessed antitumour and antiviral activities.

Glucose↗
PubMed1998

Quantitative structure-activity relationships (QSAR) for 9-anilinoacridines: a comparative analysis.

A new analysis of the quantitative structure-activity relationship (QSAR) of the antitumor activity of anilinoacridines against L1210 leukemia in mice and mouse toxicity is reported. QSAR have also been derived for the inhibitory activity of the anilinoacridines with tumor cells and their binding to DNA. These results are compared with reactivity with simple nucleophiles. The comparative analysis shows the importance of electron releasing substituents (in general negative coefficients with the Hammett parameter sigma+) throughout the various systems and the complete lack of hydrophobic interactions from DNA to cells to mice. The presence of steric terms suggests that a protein receptor is involved. The study shows that QSAR has an important role to play in improving the efficiency in the design of bioactive compounds and that care must be taken in the design of a set of congeners so that the necessary parameters are available to do the QSAR analysis. Our study illustrates the value of comparative QSAR in generalizing our understanding of chemical-biological interactions.

Amsacrine↗
PubMed1986

Determination of hydrophobic parameters by reversed-phase liquid chromatography: theory, experimental techniques, and application in studies on quantitative structure-activity relationships.

The use of RPLC retention parameters as descriptors of the hydrophobic nature of bioactive compounds has been evaluated. The relationship between the capacity factor, measured on n-alkyl-bonded stationary phases using binary eluents, and the n-octanol-water partition coefficient has been illustrated experimentally and theoretically. It is suggested that retention parameters, in particular the capacity factor (log kw) obtained by extrapolation of retention data from binary eluents to 100% water, could successfully replace the n-octanol-water partition coefficient in studies on quantitative structure-activity relationship, and that their use may result in a better correlation with biological data.

Chemical Phenomena↗
PubMed2001

Purification of microcystins.

Microcystins are an increasingly important group of bioactive compounds produced by a number of mainly planktonic cyanobacteria. They are a family of cyclic heptapeptides that cause both acute and chronic toxicity. Purified microcystins are utilised in a range of research applications including toxicological and biochemical studies, development of detection systems and the investigation of water treatment strategies. The commercial availability of purified microcystins is still relatively limited and for many projects the cost of their purchase prohibitive. The purification of microcystins from both bloom material and laboratory cultures is reviewed including a discussion on extraction, separation, and the determination of purity and yield.

Chromatography, High Pressure Liquid↗
PubMed2003

Use of synthetic adsorbents in preparative normal-phase liquid chromatography.

Normal-phase liquid chromatographic separation using polymeric synthetic adsorbents was investigated. The retention behavior of dialkyl phthalates under a hexane-isopropanol eluent system revealed that both polystyrenic and polymethacrylic adsorbents can be used for normal-phase liquid chromatography, and that the polymethacrylic adsorbent has stronger retentivity than the polystyrenic adsorbent. Applicability of these synthetic adsorbents, especially the polymethacrylic adsorbents, was verified by the separation of polyunsaturated fatty acids, schizandrin in Schisandra chinensis fruit, tocopherols and tocotrienols in vegetable oils using a 10-microm adsorbent packed into an HPLC column. Furthermore, the separation was expanded to preparative scale by using polymethacrylic adsorbents with 17- and 31-microm fine grade particle sizes. The effect of loading volume on the retention or separation was also examined, and separation was maintained up to the loading of several grams per liter adsorbent. These results demonstrate that commercially available synthetic adsorbents possess considerable performance as normal-phase chromatographic media for more precise purification of bioactive compounds. including pharmaceuticals and nutraceuticals with scale-up possibilities.

Adsorption↗
PubMed2003

Strategies for the determination of bioactive phenols in plants, fruit and vegetables.

Analytical strategies dealing with bioactive phenols in plants and foods are reviewed. These depend on the purpose of the analysis which may be classified as studies where the principal purpose is biological screening, phytochemical and/or chemical screening. Nevertheless, extraction of the phenol from the sample matrix is common and methods of achieving a suitable extract are assessed. Advances in the separation sciences and spectrometry are exploited for identification and quantification of isolated phenols. The various procedures are summarized and some typical "case studies" are presented. Two important areas are introduced briefly. Thus, plant phenols are reactive species and their ultimate fate has been relatively neglected. Studies of bioactive compounds generate a considerable volume of data making data handling and informatics important topics that warrant a separate review.

Chromatography↗
PubMed2002

Gastroprotective effect of Neem (Azadirachta indica) bark extract: possible involvement of H(+)-K(+)-ATPase inhibition and scavenging of hydroxyl radical.

The antisecretory and antiulcer effects of aqueous extract of Neem (Azadirachta indica) bark have been studied along with its mechanism of action, standardisation and safety evaluation. The extract can dose dependently inhibit pylorus-ligation and drug (mercaptomethylimidazole)-induced acid secretion with ED(50) value of 2.7 and 2 mg Kg(-1) b.w. respectively. It is highly potent in dose-dependently blocking gastric ulcer induced by restraint-cold stress and indomethacin with ED(50) value of 1.5 and 1.25 mg Kg(-1) b.w. respectively. When compared, bark extract is equipotent to ranitidine but more potent than omeprazole in inhibiting pylorus-ligation induced acid secretion. In a stress ulcer model, it is more effective than ranitidine but almost equipotent to omeprazole. Bark extract inhibits H(+)-K(+)-ATPase activity in vitro in a concentration dependent manner similar to omeprazole. It offers gastroprotection against stress ulcer by significantly preventing adhered mucus and endogenous glutathione depletion. It prevents oxidative damage of the gastric mucosa by significantly blocking lipid peroxidation and by scavenging the endogenous hydroxyl radical ((z.rad;)OH)-the major causative factor for ulcer. The (z.rad;)OH-mediated oxidative damage of human gastric mucosal DNA is also protected by the extract in vitro. Bark extract is more effective than melatonin, vitamin E, desferrioxamine and alpha-phenyl N-tert butylnitrone, the known antioxidants having antiulcer effect. Standardisation of the bioactive extract by high pressure liquid chromatography indicates that peak 1 of the chromatogram coincides with the major bioactive compound, a phenolic glycoside, isolated from the extract. The pharmacological effects of the bark extract are attributed to a phenolic glycoside which is apparently homogeneous by HPLC and which represents 10% of the raw bark extract. A single dose of 1g of raw extract per kg b.w. (mice) given in one day and application of 0.6g raw extract per kg b.w. per day by oral route over 15 days to a cumulative dose of 9g per kg was well tolerated and was below the LD(50). It is also well tolerated by rats with no significant adverse effect. It is concluded that Neem bark extract has therapeutic potential for the control of gastric hyperacidity and ulcer.

Animals↗
PubMed1998

Oleuropein, the bitter principle of olives, enhances nitric oxide production by mouse macrophages.

The Mediterranean diet, rich in fresh fruits and vegetables, has been associated with a lower incidence of cardiovascular disease and cancer, partly because of its high proportion of bioactive compounds such as vitamins, flavonoids and polyphenols. The major lipid component of such diet is the drupe-derived olive oil, that can be distinguished from other seed oils for the peculiar composition of its non-triglyceride fraction. In fact, several minor components, including polyphenols, grant the oil its particular taste and aroma. Oleuropein, the most abundant among these components, has been shown to be a potent antioxidant endowed with antiinflammatory properties. We investigated the effects of oleuropein on NO release in cell culture and its activity toward nitric oxide synthase (iNOS) expression. The results show that oleuropein dose-dependently enhance nitrite production in LPS-challenged mouse macrophages. This effect was blocked by the iNOS inhibitor L-NAME, indicating increased iNOS activity. Also, Western blot analysis of cell homogenates show that oleuropein increases iNOS expression in such cells. Taken together, our data suggest that, during endotoxin challenge, oleuropein potentiates the macrophage-mediated response, resulting in higher NO production, currently believed to be beneficial for cellular and organismal protection.

Animals↗
PubMedDate not supplied

Methodological considerations for characterizing potential antioxidant actions of bioactive components in plant foods.

The study of free radicals and antioxidants in biology is producing medical revolution that promises a new age of health and disease management. From prevention of the oxidative reactions in foods, pharmaceuticals and cosmetics to the role of reactive oxygen species (ROS) in chronic degenerative diseases including cancer, autoimmune, inflammatory, cardiovascular and neurodegenerative (e.g. Alzheimer's disease, Parkinson's disease, multiple sclerosis, Downs syndrome) and aging challenges continue to emerge from difficulties associated with methods used in evaluating antioxidant actions in vivo. Our interest presently is focused on development of neurodegeneration models based on the integrity of neuronal cells in the central nervous system and how they are protected by antioxidants when challenged by neurotoxins as well as Fenton chemistry models based on the profile of polyunsaturated fatty acids (PUFAs) for the assessment of antioxidant actions in vivo. Use continues to be made of several in vitro analytical tools to characterise the antioxidant propensity of bioactive compounds in plant foods and supplements. For example, the oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP), total oxidant scavenging capacity (TOSC), the deoxyribose assay, assays involving oxidative DNA damage, assays involving reactive nitrogen intermediates (e.g. ONOO(-)), Trolox equivalent antioxidant capacity (TEAC) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. There is need to agree governance on in vitro antioxidant methods based on an understanding of the mechanisms involved. Because some of the assays are done in non-physiological pH values, it is impossible to extrapolate the results to physiological environment. The consensus of opinion is that a mix of these tools should be used in assessing the antioxidant activities in vitro. The proof of bio-efficacy must emanate from application of reliable in vivo models where markers of baseline oxidative damage are examined from the standpoint of how they are affected by changes in diet or by antioxidant supplements.

Antioxidants↗
PubMed2000

Biotransformation of the Trichoderma metabolite 6-n-pentyl-2H-pyran-2-one by cell suspension cultures of Pinus radiata.

Cell suspension cultures of Pinus radiata metabolize the antifungal Trichoderma secondary metabolite 6-n-pentyl-2H-pyran-2-one (6PAP) (1) via hydroxylation of the pentyl side chain. Examination of the culture medium following dosing studies with 1 revealed that 79-85% of this bioactive compound had been metabolised after 144 h. At that time, 34-40% of the metabolized dose was recovered as a series of monohydroxylated isomers of 1, the principal metabolite being 5-(2-pyron-6-yl)pentan-5-ol (7).

Antifungal Agents↗