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At least 307 records · Page 17Linked to original sources
PubMed2004

In vitro gastrointestinal digestion study of broccoli inflorescence phenolic compounds, glucosinolates, and vitamin C.

Broccoli (Brassica oleracea L. var. italica cv. Marathon) inflorescences are a good source of bioactive compounds, such as phenolics (flavonoids and hydroxycinnamoyl derivatives), glucosinolates, and vitamin C. In this work, these health-promoting compounds were submitted to digestion under in vitro gastrointestinal conditions (pH, temperature, enzyme, and chemical conditions). This technique differentiated among the compounds associated with macromolecules in soluble and insoluble form and those that are freely soluble. In addition, it evaluates the chemical stability of the broccoli compounds under simulated physiological conditions. The gastric digestion of broccoli caused high losses in glucosinolates (69% loss), whereas phenolics and vitamin C presented higher stability under these conditions. Thus, there were no losses in flavonoids, a 7% loss of vitamin C, and a variable rate of loss (6-25%) in hydroxycinnamic acid derivatives. The stability of all of the compounds was affected by the in vitro intestinal conditions. Under the in vitro conditions, flavonoids and hydroxycinnamoyl acid derivatives were of low availability, due to their significant losses under these conditions, at the end of the experiment (84 and 80% loss, respectively). Vitamin C was the metabolite that showed the greater decrease after intestinal digestion (91% loss). Regarding the remaining glucosinolates, these compounds presented higher stability under intestinal conditions, rendering an availability similar to that found for phenolics (75% loss). Therefore, broccoli components were affected by gastric and/or intestinal conditions depending on the type of compound. Thus, glucosinolates were mainly degraded by gastric conditions, whereas phenolic compounds and vitamin C were degraded by intestinal conditions.

Ascorbic Acid↗
PubMed2005

Medium-sized peptides as built in carriers for biologically active compounds.

A growing number of oligopeptides of natural and/or synthetic origin have been described and considered as targeting structures for delivery bioactive compounds into various cell types. This review will outline the discovery of peptide sequences and the corresponding mid-sized oligopeptides with membrane translocating properties and also summarize de novo designed structures possessing similar features. Conjugates and chimera constructs derived from these sequences with covalently attached bioactive peptide, epitope, oligonucleotide, PNA, drug, reporter molecule will be reviewed. A brief note will refer to the present understanding on the uptake mechanism at the end of each section.

Amino Acid Sequence↗
PubMed2004

Screening and synthesis: high throughput technologies applied to parasitology.

High throughput technologies continue to develop in response to the challenges set by the genome projects. This article discusses how the techniques of both high throughput screening (HTS) and synthesis can influence research in parasitology. Examples of the use of targeted and phenotype-based HTS using unbiased compound collections are provided. The important issue of identifying the protein target(s) of bioactive compounds is discussed from the synthetic chemist's perspective. This article concludes by reviewing recent examples of successful target identification studies in parasitology.

Animals↗
PubMed2004

Novel Marine Compounds: Anticancer or Genotoxic?

In the past several decades, marine organisms have generously gifted to the pharmaceutical industries numerous naturally bioactive compounds with antiviral, antibacterial, antimalarial, anti-inflammatory, antioxidant, and anticancer potentials. But till date only few anticancer drugs (cytarabine, vidarabine) have been commercially developed from marine compounds while several others are currently in different clinical trials. Majority of these compounds were tested in the tumor xenograft models, however, lack of anticancer potential data in the chemical- and/or oncogene-induced pre-initiation animal carcinogenesis models might have cost some of the marine anticancer compounds an early exit from the clinical trials. This review critically discusses importance of preclinical evaluation, failure of human clinical trials with certain potential anticancer agents, the screening tests used, and choice of biomarkers.

Journal Article↗
PubMed2004

Immunomodulatory and antimicrobial effects of some traditional chinese medicinal herbs: a review.

The current practice of ingesting phytochemicals to support the immune system or to fight infections is based on centuries-old tradition. We review reports on seven Chinese herbs, (Aloe vera Mill. (Aloaceae), Angelica species (Umbelliferae), Astragalus membranaceus Bunge. (Leguminosae), Ganoderma lucidum (Fr.) Karst. (Ganodermataceae), Panax ginseng C.A Mey. (Araliaceae), Scutellaria species (Lamiaceae) and Zingiber officinale Rosc. (Zingiberaceae) with emphasis to their immunomodulatory and antimicrobial activities. While some of these herbaceous plants have a direct inhibitory effect on microbial organisms, we observe that each plant has at least one compound that selectively modulates cells of the immune system. The successful derivation of pure bioactive compounds from Ganoderma lucidum, ginseng and Zingiber officinale supports the traditional practice of using these plants to stimulate the immune system. As many modern drugs are often patterned after phytochemicals, studying the influence of each compound on immune cells as well as microbes can provide useful insights to the development of potentially useful new pharmacological agents.

Animals↗
PubMed2006

Anti-inflammatory effects and mechanisms of the ethanol extract of Evodia rutaecarpa and its bioactive components on neutrophils and microglial cells.

Evodia rutaecarpa is commonly used as an anti-inflammatory drug in traditional Chinese medicine. We previously identified four bioactive compounds (dehydroevodiamine (I), evodiamine (II), rutaecarpine (III), and synephrine (IV)) from the ethanol extract of E. rutaecarpa, but their effects and mechanism(s) of action remain unclear. To study the anti-inflammatory potential and the possible underlying mechanism(s), their effects on phorbol-12-myristate-13-acetate (PMA)- and N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced reactive oxygen species production in neutrophils was studied, as well as lipopolysaccharide (LPS)-induced nitric oxide (NO) production and inducible NO synthetase (iNOS) expression in microglial cells. The ethanol extract of E. rutaecarpa displayed potent antioxidative effects against both PMA- and fMLP-induced reactive oxygen species production in neutrophils (with IC50 values of around 2.7-3.3 microg/ml). Although less potent than the ethanol extract of E. rutaecarpa, compounds I-IV all concentration-dependently inhibited PMA- and fMLP-induced reactive oxygen species production, with compound IV consistently being the most potent agent among these active components. The antioxidative effects of the ethanol extract of E. rutaecarpa and these compounds were partially due to inhibition (10%-33%) of NADPH oxidase activity, a predominant reactive oxygen species-producing enzyme in neutrophils, and to a minor extent to their direct radical-scavenging properties. The ethanol extract of E. rutaecarpa also inhibited LPS-induced NO production (with an IC50 of around 0.8 microg/ml) and iNOS upregulation in microglial cells that was partially mimicked by compounds I, II, and III, but not compound IV. Our results suggest that the ethanol extract of E. rutaecarpa and its four bioactive components all exhibited anti-inflammatory activities which could be partially explained by their different potentials for inhibiting NADPH oxidase-dependent reactive oxygen species and/or iNOS-dependent NO production in activated inflammatory cells.

Alkaloids↗
PubMed2005

The molecular retention mechanism in reversed-phase liquid chromatography of meso-ionic compounds by quantitative structure-retention relationships (QSRR).

Absorption, distribution, metabolism, and excretion (ADME) properties are of invaluable importance to a bioactive compound. Permeation process is one of the most widely studied by many different techniques. Among them, reversed-phase liquid chromatography (RP-LC) is proving to be of great interest, in which retention time can provide some insights on the hydrophobic interaction behavior. A series of antiprotozoal meso-ionic 1,3,4-thiadiazolium-3-aminides were studied in order to obtain the retention-time data through two different organic modifiers using a commercially available Supelcosil ABZ(+) Plus column. MeOH/buffer mobile phase provided the best results in assessing the hydrophobicity of these compounds as compared to MeCN. Quantitative Structure-Retention Relationships (QSRR) models were built to identify the physicochemical properties that govern the process by using PLS analysis. VolSurf descriptors extracted from water (H(2)O), hydrophobic (DRY), amide N-atom (N(1)) and carbonyl O-atom (O) probes showed that the retention is positively correlated to the molecules size and shape, hydrophobic pattern, and dispersion forces. Hydrogen bonding depicts the solvent force considering the donor and acceptor differences between MeOH and MeCN organic modifiers.

Antiprotozoal Agents↗
PubMedDate not supplied

Dye coupling in horizontal cells of developing rabbit retina.

In the mature rabbit retina, two classes of horizontal cells, A type and B type, provide lateral inhibition in the outer plexiform layer (OPL) and spatially modify the activation of bipolar cells by photoreceptors. Gap junctions connecting homologous horizontal cells determine the extent to which this inhibitory activity spreads laterally across the OPL. Little is currently known about the expression of gap junctions in horizontal cells during postnatal development or how cell-cell coupling might contribute to subsequent maturational events. We have examined the morphological attributes and coupling properties of developing A and B type horizontal cells in neonatal rabbit retina using intracellular injections of Lucifer Yellow and Neurobiotin. Prelabeling with DAPI permitted the targeting of horizontal cell bodies for intracellular injection in perfused preparations of isolated retina. A and B type horizontal cells were identifiable at birth although their dendritic field sizes had not reached adult proportions and their synaptic contacts in the OPL were minimal. Both cell types exhibited homologous dye coupling at birth. Similar to that seen in the adult, no heterologous coupling was observed, and homologous coupling among A type cells was stronger than that observed among B type cells. The spread of tracer compounds through gap junctions of morphologically immature horizontal cells suggests that ions and other small, bioactive compounds may likewise spread through coupled, horizontal networks to coordinate the subsequent maturational of emerging outer plexiform layer pathways.

Animals↗
PubMed2001

Isolation of an antimicrobial compound from Impatiens balsamina L. using bioassay-guided fractionation.

By using brine shrimp (Artemia salina) lethality test-guided fractionation, a single bioactive compound (LC(50)=26 ppm) was isolated from the 95% ethanol extract of the dried aerial parts of Impatiens balsamina L. and subsequently identified as 2-methoxy-1,4-naphthoquinone (MNQ). The structure of MNQ was confirmed by UV, FT-IR, MS, and 1-and 2-D NMR spectroscopy. The antimicrobial activity of MNQ was evaluated using 12 bacterial and eight fungal strains. Five gram-positive and two gram-negative bacteria as well as all eight fungi (including multi-drug resistant strains) tested were highly sensitive to MNQ. A tea prepared according to traditional methods was found to contain sufficient MNQ to account for its antimicrobial properties.

Animals↗
PubMed2003

Marine pharmacology in 2000: antitumor and cytotoxic compounds.

During 2000, marine antitumor pharmacology research aimed at the discovery of novel antitumor agents was published in 85 peer-reviewed articles. The purpose of this article is to present a structured review of the antitumor and cytotoxic properties of 143 marine natural products, many of them novel compounds that belong to diverse structural classes, including polyketides, terpenes, steroids and peptides. The organisms yielding these bioactive compounds comprised a taxonomically diverse group of marine invertebrate animals, algae, fungi and bacteria. Antitumor pharmacological studies were conducted with 19 marine natural products in a number of experimental and clinical models that defined or further characterized their mechanisms of action. Potentially promising in vitro cytotoxicity data generated with murine and human tumor cell lines were reported for 124 novel marine chemicals with as yet undetermined mechanisms of action. Noteworthy is the fact that marine anticancer research clearly remains a multinational effort, involving researchers from Austria, Australia, Brazil, Canada, England, France, Germany, Greece, Indonesia, Italy, Japan, New Zealand, Russia, Spain, South Korea, Switzerland, Taiwan, the Netherlands and the United States. Finally, this 2000 overview of the marine pharmacology literature highlights the fact that the discovery of novel marine antitumor agents continued at the same high level of research activity as during 1998 and 1999.

Animals↗
PubMed2004

Marine pharmacology in 2001-2: antitumour and cytotoxic compounds.

During 2001 and 2002, marine antitumour pharmacology research aimed at the discovery of novel antitumour agents was published in 175 peer-reviewed articles. The purpose of this paper is to present a structured Review of the antitumour and cytotoxic properties of 97 marine natural products, many of them novel compounds that belong to diverse structural classes, including polyketides, terpenes, steroids, and peptides. The organisms yielding these bioactive compounds comprise a taxonomically diverse group of marine invertebrate animals, algae, fungi and bacteria. Antitumour pharmacological studies were conducted with 30 structurally characterised natural marine products in a number of experimental and clinical models which further defined their mechanisms of action. Particularly potent in vitro cytotoxicity data generated with murine and human tumour cell lines was reported for 67 novel marine chemicals with as yet undetermined mechanisms of action. Noteworthy, is the fact that marine anticancer research was sustained by a collaborative effort, involving researchers from Australia, Brazil, Canada, Denmark, Egypt, France, Germany, Italy, Japan, Netherlands, New Zealand, The Philippines, Russia, Singapore, South Korea, Thailand, Taiwan, Turkey, Spain, Switzerland, Taiwan, Thailand, Turkey, and the United States. Finally, this 2001-2 overview of the marine pharmacology literature highlights the fact that the discovery of novel marine antitumour agents has continued at the same pace as during 1998, 1999 and 2000.

Antineoplastic Agents↗
PubMed2006

Simultaneous quantification of three major bioactive triterpene acids in the leaves of Diospyros kaki by high-performance liquid chromatography method.

The leaf of Diospyros kaki, which is a traditional Chinese medicine, has been used for the treatment of various diseases. In order to improve the quality assurance of the leaves of D. kaki, derived extracts and phytomedicines, a simple, rapid and accurate high-performance liquid chromatography (HPLC) method was developed to simultaneously assess the three bioactive triterpene acids: barbinervic acid (BA) and its epimer, rotungenic acid (RA), along with 24-hydroxy ursolic acid (HA). This HPLC assay was performed on a reversed-phase C18 column with methanol and aqueous H3PO4 as the mobile phase and using a monitoring wavelength at 210 nm. This method was successfully applied to quantify these three bioactive triterpene acids in five different solvent extracts of the leaves of D. kaki and in the leaves from six different locations in China. The results demonstrated the total content and quantity of each of the main bioactive compounds were strongly dependent on the extraction solvents and locations, indicating that the quality control of the bioactive ingredients in the leaves of D. kaki, derived extracts and phytomedicines is critical to ensure its clinical benefits. The content of the total triterpenoids was also determined by the less selective colorimetric method, and the comparison with the HPLC method was given.

Calibration↗
PubMed2006

Biomimetic approach to biomembrane models studies: medium influence on the interaction kinetics of some phenylurea derivatives herbicides.

The ability of herbicides to interact with cell membranes outer lipid layer and subsequently to penetrate inside cells can be a prerequisite for exhibiting a toxic activity for both the directly exposed workers and the end consumers as the herbicides are present in the soil and water. The effect exerted by fenuron, chlorotoluron, metobromuron, monolinuron, and chlorbromuron, five structurally similar phenylurea herbicides, on the thermotropic behavior of model membranes, represented by dimyristoylphosphatidylcholine (DMPC) vesicles, was investigated by differential scanning calorimetry. The examined compounds, when dispersed in liposomes during their preparation, exerted a different action on the gel-to-liquid crystal phase transition of DMPC multilamellar vesicles. The ability of phenylurea herbicides, as a finely powdered solid, to migrate through an aqueous medium and interact with biomembrane models was also studied. This transfer process was compared with these compounds intermembrane transfer from herbicide-loaded liposomes to empty ones. These processes can mimic absorption kinetics mediated by hydrophilic or lipophilic media. Different rate and entity of interaction occurred between model membranes and solid phenylurea herbicides. Different behavior was observed by considering the time-dependent studies carried out by contacting, for increasing times, equivalent amounts of empty DMPC vesicles with phenylurea herbicide-loaded ones; all compounds were able to migrate from loaded to empty DMPC vesicles. Thus, phenylurea herbicides are able to reach and penetrate biological membranes when dispersed in a lipophilic or hydrophilic medium; these processes are related to the substituents present on the compounds backbone. The obtained experimental results seem to validate the employed strategy to study the ability of bioactive compounds to both interact with biological membranes and be adsorbed inside a membrane mimicking a biological cell when dispersed in a lipophilic or hydrophilic medium.

Calorimetry, Differential Scanning↗
PubMed2002

[Laggera pterodonta--a Yunnan Herbal Medicine]

OBJECTIVE: A systematic study of Laggera pterodonta was performed in order to identify its bioactive compounds. METHODS: Solvent partition and column chromatography used to isolate and purify Laggera pterodonta compounds. The isolated compounds were further elucidated by high field NMR spectroscopy. RESULTS: Fifty-two compounds were separated and the structures of 39 compounds were elucidated. Twenty-four compounds have not been previously reported. For example, the structure of compound 19, a previously undetected compound was elucidated as 4gamma, 9alpha,11-triol-enantio-eudesmane using both 1D and 2D NMR spectroscopy. Major secondary metabolites of the Laggera pterodonta included eudesmane-type sesquiterpenes and flavone derivatives. CONCLUSION: A systematic study of a yunnan herbal medicine Laggera pterodonta resvealed several novel compounds that may have clinical significance. Further in vivo animal studies should be performed to assess their bioactive role.

Journal Article↗
PubMed1999

The hidden component of size in two-dimensional fragment descriptors: side effects on sampling in bioactive libraries.

We have carried out a number of sampling experiments in libraries of bioactive compounds to illustrate how size biases introduced by two-dimensional (2D) fragment distance functions may provide misleading information about the diversity of compound subsets. The number of different biological targets covered by a given subset is used as a measure of bioactive diversity, and it is considered to be the relevant property with which 2D diversity should correlate. Since the nature of the size biases depends on the way in which 2D distance is computed, we investigated three different methods of calculating distance. Use of 1-Tanimoto as a dissimilarity measure leads to the spurious conclusion that collections of structurally small compounds are inherently more diverse than other collections which may cover a broader range of sizes and more biological targets. XOR or squared Euclidean distance, by contrast, shows a preference for subsets of structurally larger compounds, but this does not appear to have as many adverse consequences in terms of target coverage. A simple product of 1-Tanimoto and XOR tends to equalize the opposing size effects of the two component distance functions and leads to a relatively unbiased means of comparing structures. Results here suggest that careful consideration should be given to the way in which chemical structures are compared whenever 2D fragment descriptors are used.

Drug Design↗
PubMed2005

Study of anticancer activities of muscadine grape phenolics in vitro.

Muscadine grapes have unique aroma and flavor characteristics. Although a few studies reported high polyphenols content of muscadine grapes, little research has been conducted to evaluate the phenolic compounds bioactivities in any muscadine grape cultivar. The objective of this study was to evaluate the effect of phenolic compounds in muscadine grapes on cancer cell viability and apoptosis. Four cultivars of muscadine (Carlos, Ison, Noble, and Supreme) were assessed in this study. Phenolic compounds were extracted from muscadine skins and further separated into phenolic acids, tannins, flavonols, and anthocyanins using HLB cartridge and LH20 column. Some individual phenolic acids and flavonoids were identified by HPLC. Anthocyanin fractions were more than 90% pure. The effect of different fractions on the viability and apoptosis of two colon cancer cell lines (HT-29 and Caco-2) was evaluated. A 50% inhibition of cancer cell population growth for the two cell lines was observed at concentrations of 1-7 mg/mL for crude extracts. The phenolic acid fractions showed a 50% inhibition at the level of 0.5-3 mg/mL. The greatest inhibitory activity was found in the anthocyanin fraction, with a 50% inhibition at concentrations of approximately 200 microg/mL in HT-29 and 100-300 microg/mL in Caco-2. Anthocyanin fractions also resulted in 2-4 times increase in DNA fragmentation, indicating the induction of apoptosis. These findings suggest that polyphenols from muscadine grapes may have anticancer properties.

Antineoplastic Agents↗
PubMed1996

(R)-2,3-O-Cyclohexylideneglyceraldehyde, a Versatile Intermediate for Asymmetric Synthesis of Homoallyl and Homopropargyl Alcohols in Aqueous Medium.

Zn-mediated allylation and propargylation of (R)-2,3-O-cyclohexylideneglyceraldehyde (1) in aqueous medium following Luche's procedure afforded the anti homoallylic 3 and homopropargylic 8 alcohols in good yield and with high stereoselectivity. Crotylation of 1 under similar conditions afforded appreciable amounts of erythro-5 and threo-6 alcohols. In each case, the diastereo alcohols are separable by column chromatography. Compound 8 on appropriate chemical manipulation of its functionalities gave the (S)-enantiomer of (R)-13, a useful synthon of LTB(4). Compound 3 on chemical elaboration afforded a diversely functionalized triol derivative 15, a potentially useful synthon for many bioactive compounds.

Journal Article↗
PubMed2005

Antimicrobial activities of Eugenol and Cinnamaldehyde against the human gastric pathogen Helicobacter pylori.

BACKGROUND: Eradication of Helicobacter pylori is an important objective in overcoming gastric diseases. Many regimens are currently available but none of them could achieve 100% success in eradication. Eugenol and cinnamaldehyde that are commonly used in various food preparations are known to possess antimicrobial activity against a wide spectrum of bacteria. AIM: The present study was performed to assess the in vitro effects of eugenol and cinnamaldehyde against indigenous and standard H. pylori strains, their minimum inhibitory concentrations (MICs) and time course lethal effects at various pH. METHODS: A total of 31 strains (29 indigenous and one standard strain of H. pylori ATCC 26695, one strain of E. coli NCIM 2089) were screened. Agar dilution method was used for the determination of drug sensitivity patterns of isolates to the commonly used antibiotics and broth dilution method for the test compounds. RESULTS: Eugenol and cinnamaldehyde inhibited the growth of all the 30 H. pylori strains tested, at a concentration of 2 mug/ml, in the 9th and 12th hours of incubation respectively. At acidic pH, increased activity was observed for both the compounds. Furthermore, the organism did not develop any resistance towards these compounds even after 10 passages grown at sub-inhibitory concentrations. CONCLUSION: These results indicate that the two bioactive compounds we tested may prevent H. pylori growth in vitro, without acquiring any resistance.

Acrolein↗