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At least 613 records · Page 34Linked to original sources
PubMed2006

Determination of five components in Ixeris sonchifolia by high performance liquid chromatography.

A high performance liquid chromatography (HPLC) method was developed for the simultaneous quantification of five major active ingredients (markers) in Ixeris sonchifolia (Bge.) Hance, namely chlorogenic acid, caffeic acid, luteolin-7-O-beta-D-glucuronide, luteolin-7-O-beta-D-glucoside and luteolin. Samples were extracted with 70% methanol. The chromatographic separation was performed on a Hypersil ODS(2) column (250 mm x 4.6 mm i.d.; 5 microm) with a gradient of acetonitrile and 0.5% (v/v) aqueous acetic acid, at a flow rate of 1.0 ml/min, detected at 335 nm. Five regression equations showed good linear relationships (r(2)>0.999) between the peak area of each marker and concentration. The assay was reproducible with overall intra- and inter-day variation of less than 3.2%. The recoveries, measured at three concentration levels, varied from 94.1% to 100.7%. This assay was successfully applied to the determination of the 5 bioactive compounds in 18 samples. The results indicated that the developed assay method was rapid, accurate, reliable and could be readily utilized as a quality control method for I. sonchifolia (Bge.) Hance.

Asteraceae↗
PubMed2006

Indian black scorpion (Heterometrus bengalensis Koch) venom induced antiproliferative and apoptogenic activity against human leukemic cell lines U937 and K562.

Venoms are rich source of several bioactive compounds that possess therapeutic potentials. The different constituents of scorpion venom can modulate cell proliferation, cell growth and cell cycle. In the present communication, the cytotoxic activity of Indian black scorpion (Heterometrus bengalensis) venom was explored on human leukemic U937 and K562 cells. Scorpion venom induced U937 and K562 cell growth inhibition and the IC(50) value calculated to be 41.5 microg/ml (U937) and 88.3 microg/ml (K562). The scorpion venom showed characteristic features of apoptosis such as membrane blebbing, chromatin condensation and DNA degradation in both the cells as evidenced by confocal, fluorescence, scanning electron microscopy. Scorpion venom (IC(50) dose, 48 h) induced DNA fragmentation as evidenced by comet formation. Flow-cytometric assay revealed a significant amount of apoptotic cells (early and late) due to scorpion venom treatment. The venom induced cell cycle arrest was observed with maximum cell accumulation at sub-G(1) phase. Thus, the Indian scorpion (H. bengalensis) venom possessed antiproliferative, cytotoxic and apoptogenic activity against human leukemic cells.

Animals↗
PubMed2005

Evodiamine inhibits in vitro angiogenesis: Implication for antitumorgenicity.

Evodiamine, the major bioactive compound isolated from Chinese herbal drug named Wu-Chu-Yu, has been reported to exhibit anti-tumor growth and metastasis. However, the effect of evodiamine on angiogenesis remains to be investigated. We used the fresh medium containing evodiamine or human lung adenocarcinoma cell (CL1 cells) derived conditioned media free of evodiamine to test their capability to induce in vitro angiogenesis, i.e., human umbilical vein endothelial cells (HUVECs) tube formation and invasion. We demonstrated that evodiamine could directly inhibit in vitro HUVECs tube formation and invasion. Locally administered evodiamine also inhibited the in vivo angiogenesis in the chick embryo chorioallantoic membrane (CAM) assay. The gene expression of vascular endothelial growth factor (VEGF) and the p44/p42 mitogen-activated protein kinase (MAPK, ERK) that correlated with endothelial cells angiogenesis were inhibited by evodiamine. We found that the evodiamine-treated CL1 cells derived conditioned medium showed decreased VEGF release and reduced ability of inducing in vitro tube formation. After the collection of conditioned media, the VEGF expression of remaining CL1 cells were determined by Western analyses and revealed that evodiamine decreased VEGF expression. Moreover, administration of recombinant human VEGF(165) (rhVEGF(165)) induced tube formation and ERK phosphorylation by HUVECs, and partially attenuated inhibitory effect of evodiamine. From these results, we suggested that evodiamine is a potent inhibitor of angiogenesis. The mechanism might involve at least the inhibition of VEGF expression, probably through repression of ERK phosphorylation.

Angiogenesis Inhibitors↗
PubMed2006

Ganoderic acid T from Ganoderma lucidum mycelia induces mitochondria mediated apoptosis in lung cancer cells.

Ganoderma lucidum is a well-known traditional Chinese medicinal herb containing many bioactive compounds. Ganoderic acid T (GA-T), which is a lanostane triterpenoid purified from methanol extract of G. lucidum mycelia, was found to exert cytotoxicity on various human carcinoma cell lines in a dose-dependent manner, while it was less toxic to normal human cell lines. Animal experiments in vivo also showed that GA-T suppressed the growth of human solid tumor in athymic mice. It markedly inhibited the proliferation of a highly metastatic lung cancer cell line (95-D) by apoptosis induction and cell cycle arrest at G(1) phase. Moreover, reduction of mitochondria membrane potential (Delta psi(m)) and release of cytochrome c were observed during the induced apoptosis. Our data further indicate that the expression of proteins p53 and Bax in 95-D cells was increased in a time-dependent manner, whereas the expression of Bcl-2 was not significantly changed; thus the ratio of Bcl-2/Bax was decreased. The results show that the apoptosis induction of GA-T was mediated by mitochondrial dysfunctions. Furthermore, stimulation of the activity of caspase-3 but not caspase-8 was observed during apoptosis. The experiments using inhibitors of caspases (Z-VAD-FMK, Z-DEVD-FMK and Z-IETD-FMK) confirmed that caspase-3 was involved in the apoptosis. All our findings demonstrate that GA-T induced apoptosis of metastatic lung tumor cells through intrinsic pathway related to mitochondrial dysfunction and p53 expression, and it may be a potentially useful chemotherapeutic agent.

Animals↗
PubMed2006

Production of an antimicrobial substance against Cryptococcus neoformans by Paenibacillus brasilensis Sa3 isolated from the rhizosphere of Kalanchoe brasiliensis.

An antifungal substance produced by Paenibacillus brasilensis strain Sa3 was preliminary characterized and showed to be stable after treatment with different enzymes and organic solvents and at a wide range of pH, and presented a molecular weight between 3 and 10 kDa. In vitro antagonism of this strain towards Cryptococcus neoformans was investigated by optical and electronic microscopic analyses and a fungicidal effect on C. neoformans was observed. Ultrastructural analysis showed intense changes on the fungus when it was paired cultured with strain Sa3, mainly the detachment of the capsule from the cell wall and the presence of altered organelles in the cytoplasm. This novel antifungal substance produced by P. brasilensis Sa3 may represent a new insight in antifungal therapy mainly against emergent fungi. Also, prospective studies on rhizobacteria of plants as Kalanchoe brasiliensis may offer a potential source for the discovery of bioactive compounds with medical value.

Antibiosis↗
PubMed2004

In vitro chemopreventive activity of Camellia sinensis, Ilex paraguariensis and Ardisia compressa tea extracts and selected polyphenols.

Several herbal teas contain bioactive compounds that have been associated with a lower risk of chronic diseases including cancer. The aim of this study was to evaluate the chemopreventive activity of tea aqueous extracts and selected constituent pure polyphenols using a battery of in vitro marker systems relevant for the prevention of cancer. The effects of (-) epigallocatechin gallate (EGCG), quercetin (Q), gallic acid (GA), green tea (GT, Camellia sinensis), ardisia tea (AT, Ardisia compressa) and mate tea (MT, Ilex paraguariensis) extracts were tested. Cytotoxicity, TPA-induced ornithine decarboxylase (ODC) and quinone reductase (QR) activities were evaluated in vitro using HepG2 cells. The topoisomerase inhibitory activity was also tested, using the Saccharomyces cerevisiae yeast system. Results suggest that MT, AT and GT are cytotoxic to the HepG2 cells, with MT demonstrating dominant cytotoxicity. EGCG showed greater cytotoxicity than Q and GA against HepG2 cells. The greatest inhibition (82%) of TPA-induced ODC activity was shown by Q, with 25 microM (IC50 = 11.90 microM). Topoisomerase II, but not topoisomerase I, was the cellular target of MT, AT, EGCG, Q and GA, which acted mainly as true catalytic inhibitors. The cytotoxic activity and the inhibition of topoisomerase II may contribute to the overall chemopreventive activity of AT and MT extracts. Ardisia and mate teas may thus share a public health potential as chemopreventive agents.

Ardisia↗
PubMed2005

What is a pheromone? Mammalian pheromones reconsidered.

Pheromone communication is a two-component system: signaling pheromones and receiving sensory neurons. Currently, pheromones remain enigmatic bioactive compounds, as only a few have been identified, but classical bioassays have suggested that they are nonvolatile, activate vomeronasal sensory neurons, and regulate innate social behaviors and neuroendocrine release. Recent discoveries of potential pheromones reveal that they may be more structurally and functionally diverse than previously defined.

Animals↗
PubMed2006

Detection and identification of oligopeptides in Microcystis (cyanobacteria) colonies: toward an understanding of metabolic diversity.

Cyanobacteria and particularly Microcystis sp. (Chroococcales) are known to produce a multitude of peptide metabolites. Here we report on the mass spectral analysis of cyanobacterial peptides in individual colonies of Microcystis sp. collected in a drinking water reservoir. A total number of more than 90 cyanopeptides could be detected, 61 of which could be identified either as known peptides or new structural variants of known peptide classes. For 18 new peptides flat structures are proposed. New congeners differed from known ones mainly in chlorination (aeruginosins), methylation (microginins), or amino acid sequences (cyanopeptolins). The high number of peptides and especially the new peptides underline the capability of Microcystis strains as producers of a high diversity of potentially bioactive compounds.

Animals↗
PubMed2006

Current state, achievements, and future prospects of polymeric micelles as nanocarriers for drug and gene delivery.

Polymeric micelles, self-assemblies of block copolymers, are promising nanocarrier systems for drug and gene delivery. Until now, several micellar formulations of antitumor drugs have been intensively studied in preclinical and clinical trials, and their utility has been demonstrated. Even compared with long-circulating liposomes, polymeric micelles might have several advantages, such as controlled drug release, tissue-penetrating ability and reduced toxicity such as hand-foot syndrome and hypersensitivity reaction. Importantly, critical features of the polymeric micelles as drug carriers, including particle size, stability, and loading capacity and release kinetics of drugs, can be modulated by the structures and physicochemical properties of the constituent block copolymers. Also, nano-engineering of block copolymers might allow the preparation of polymeric micelles with integrated smart functions, such as specific-tissue targetability, as well as chemical or physical stimuli-sensitivity. Thus, polymeric micelles are nanotechnology-based carrier systems that might exert the activity of potent bioactive compounds in a site-directed manner, ensuring their effectiveness and safety in the clinical use.

Animals↗
PubMed2004

Sablacaurin A and B, two 19-nor-3,4-seco-lanostane-type triterpenoids from Sabal causiarum and Sabal blackburniana, respectively.

In search for bioactive compounds from Sabal species, sablacaurin A [25-ethyl,23-methyl-19-nor-24-methylene-3,4-seco-4(28)-lanosten-10,3-olide] and sablacaurin B [24-ethyl,24-methyl-19-nor-3,4-seco-4(28),25(26)-lanostadiene-10,3-olide], the first 19-nor lanostane derivatives of the 3,4-seco type with a spiro element, have been isolated from the leaves of Sabal causiarum and Sabal blackburniana respectively, together with the known squalene (S. blackburniana) and ss-sitosterol (S. causiarum). From leaves of Sabal peregrina, the known triterpenes 3-oxo-24-methylenecycloartane and 24-methylcycloart-25(26)-en-3-one were isolated. The structures of these compounds were established from spectroscopic studies.

Molecular Structure↗
PubMed2005

4-benzyl-3-phenyl-5H-furan-2-one, a vasodilator isolated from Malbranchea filamentosa IFM 41300.

Screening of Malbranchea filamentosa IFM 41300 for bioactive compounds led to the identification of 4-benzyl-3-phenyl-5H-furan-2-one (1) as a vasodilator and erythroglaucin (2). The structure of 1 was established on the basis of spectroscopic and chemical investigations. Compound 1 inhibited Ca2+-induced vasocintraction in aortic rings pretreated with high K+ (60mM) or norepinephrine. Finally, compound 1 did not exhibit activity against human pathogenic microorganisms.

Animals↗
PubMed2005

Satoshi Omura: in pursuit of nature's bounty.

Professor Satoshi Omura has spent over 40 years searching for bioactive compounds in naturally occurring microorganisms, discovering more than 330 biomedically and commercially significant compounds in the process. The discovery, development and delivery of the drug ivermectin has pioneered the way for subsequent partnerships between the public and private sectors, as well as international collaborations and drug donation programmes. It has involved a variety of ground-breaking steps, providing a curative drug that will help rid Africa and the world of at least one of the most devastating of all human diseases, onchocerciasis. It has also improved the health of pets and livestock around the globe, and encouraged development of a community-based delivery mechanism that could herald a revolution in public health care in Africa.

Animals↗
PubMed2006

Spectroscopic studies of 2-(2-bromo-ethyl)-6-nitro-benzo[de]isoquinolene-1,3-dione in water/alkanol mixed solvents and nonionic micelle of Igepal CO series.

Spectroscopic studies of newly synthesized bioactive compound 2-(2-bromo-ethyl)-6-nitro-benzo[de]isoquinolene-1,3-dione (BNBIO) have been carried out in polar aprotic solvent, viz. acetonitrile, tetrahydrofuran, 1,4-dioxan, ethylene glycol, dimethyl formamide, and polar protic solvent, viz. methanol, ethanol, propanol, water. Variation in absorbance of BNBIO in water-methanol, water-ethanol and water-propanol mixtures at their different compositions have been observed. Absorption behaviour of the dye has been studied in poly(oxyethylene) nonylphenol surfactants Igepal CO 630, Igepal CO 720 and Igepal CO 890 containing same hydrophobic tail and different numbers of poly(oxyethylene) groups. Experimental results of the BNBIO nonionic micelles have been explained in terms of 1:1 electron donor-acceptor (EDA) complexation and the complexation equilibrium becomes suppressed with increasing number of poly(oxyethylene) residue on the Igepal surfactant. Variation in binding constant of dye-micelle complexation has been rationalized considering a competitive equilibrium process between the BNBIO-water interactions.

Alcohols↗
PubMed2005

Phenotypic and genotypic characterization of mutants of the virginiamycin producing strain 899 and its relatedness to the type strain of Streptomyces virginiae.

A representative set of 19 mutants, with a known genealogy, of the virginiamycin producing strain Streptomyces virginiae 899 was investigated phenotypically and genotypically. Colour of the aerial and substrate mycelium were very variable both among spontaneous variants and those obtained after induced mutagenesis. At genotypic level, all mutants showed nearly identical BOX patterns, not reflecting the phenotypic heterogeneity observed. More than 40 years of forced mutational pressure did not cause huge chromosomal distortions but was most likely limited to base substitutions. The species S. virginiae, including besides producers of virginiamycin the type strain and non-type strains producing other bioactive compounds, is genomically heterogeneous on the basis of BOX-PCR fingerprinting and DNA-DNA hybridizations. The virginiamycin producing strain 899 does not belong to the species S. virginiae despite its phenotypic similarity to the latter.

Base Composition↗
PubMed2005

Bringing medicinal plants into cultivation: opportunities and challenges for biotechnology.

Consumption of herbal medicines is widespread and increasing. Harvesting from the wild, the main source of raw material, is causing loss of genetic diversity and habitat destruction. Domestic cultivation is a viable alternative and offers the opportunity to overcome the problems that are inherent in herbal extracts: misidentification, genetic and phenotypic variability, extract variability and instability, toxic components and contaminants. The use of controlled environments can overcome cultivation difficulties and could be a means to manipulate phenotypic variation in bioactive compounds and toxins. Conventional plant-breeding methods can improve both agronomic and medicinal traits, and molecular marker assisted selection will be used increasingly. There has been significant progress in the use of tissue culture and genetic transformation to alter pathways for the biosynthesis of target metabolites. Obstacles to bringing medicinal plants into successful commercial cultivation include the difficulty of predicting which extracts will remain marketable and the likely market preference for what is seen as naturally sourced extracts.

Biotechnology↗
PubMed2004

Techniques: Bioprospecting historical herbal texts by hunting for new leads in old tomes.

Ethnobotany has led to the identification of novel pharmacological agents but many challenges to using ethnobotany as a research tool remain. In particular, the loss of traditional knowledge together with the advent of high-throughput screening has made ethnobotanical techniques laborious and potentially unnecessary. However, historical herbal texts provide a preexisting resource that documents the traditional uses of various species as medicines. As generational losses of traditional knowledge accrue, these herbal texts become increasingly valuable. The methodology for extracting useful information contained within these resources had been cumbersome and consuming. However, the application of new bioinformatics data-mining systems to herbal texts holds great promise for identifying novel pharmacotherapeutic leads for bioactive compounds.

Ethnobotany↗
PubMed2005

Toxic potential of five freshwater Phormidium species (Cyanoprokaryota).

Among the Cyanoprokaryota (blue-green algae), the genus Phormidium has thus far rarely been studied with respect to toxin production and potentially resulting human and environmental health effects. We here show that five previously unexplored freshwater species of this genus (Ph. bijugatum, Ph. molle, Ph. papyraceum, Ph. uncinatum, Ph. autumnale) are indeed capable of producing bioactive compounds. Phormidium extracts caused weight loss as well as neuro/hepatotoxic symptoms in mice, and in the case of Ph. bijugatum even death. Very low levels of saxitoxins and microcystins, as confirmed by ELISA, were insufficient to explain this toxicity and the differing toxic potencies of the Phormidium species. Qualitative HPLC analyses confirmed different substance patterns and in the future could aid in the separation of fractions for more detailed substance characterisation. The results in vivo were confirmed in vitro using cells of human, mouse and fish. The fish cells responded least sensitive but proved useful in studying the temperature dependence of the toxicity by the Phormidium samples. Further, the human cells were more sensitive than the mouse cells thus suggesting that the former may be a more appropriate choice for studying the impact of Phormidium to man. Among the human cells, two cancer cell lines were more responsive to one of the samples than a normal cell line, thereby indicating a potential anti-tumour activity. Thus, the five freshwater Phormidium species should be considered in environmental risk assessment but as well, as a source of therapeutic agents.

Animals↗
PubMed2005

Purification and characterization of an irreversible serine protease inhibitor from skin secretions of Bufo andrewsi.

Amphibian skin secretions contain many bioactive compounds. In the present work, an irreversible serine protease inhibitor, termed baserpin, was purified for the first time from the skin secretions of toad Bufo andrewsi by successive ion-exchange and gel-filtration chromatography. Baserpin is a single chain glycoprotein, with an apparent molecular weight of about 60 kDa in SDS-PAGE. Baserpin is an irreversible inhibitor and effectively inhibits the catalytic activity of trypsin, chymotrypsin and elastase. SDS-stable baserpin-trypsin complex could be seen in SDS-PAGE indicates that it possibly belongs to the serpin superfamily. According to the association rates determined, baserpin is a potent inhibitor of bovine trypsin (4.6 x 10(6) M(-1) s(-1)), bovine chymotrypsin (8.9 x 10(6) M(-1) s(-1)) and porcine elastase (6.8 x 10(6) M(-1) s(-1)), whereas it shows no inhibitory effect on thrombin. The N-terminal sequence of baserpin is HTQYPDILIAKPXDK, which shows no similarity with other known serine protease inhibitors.

Amino Acid Sequence↗