Search results for "LTE"
showing 10 items of 4531 documents
Steroidal saponins from Smilax medica and their antifungal activity.
2005
Three new steroidal saponins (1-3) were isolated from the roots of Smilax medica, together with the known disporoside A (4). The structures of the new compounds were elucidated mainly by extensive spectroscopic analysis (1D and 2D NMR, FABMS, and HRESIMS). Compounds 1, 2, and 4 demonstrated weak antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata, and C.tropicalis, with MIC values between 12.5 and 50 microg/mL.
Possible Fungistatic Implications of Betulin Presence in Betulaceae Plants and their Hymenochaetaceae Parasitic Fungi
2010
Betulin and its derivatives (especially betulinic acid) are known to possess very interesting prospects for their application in medicine, cosmetics and as bioactive agents in pharmaceutical industry. Usually betulin is obtained by extraction from the outer layer of a birch bark. In this work we describe a simple method of betulin isolation from bark of various species of Betulaceae trees and parasitic Hymenochaetaceae fungi associated with these trees. The composition of the extracts was studied by GC-MS, whereas the structures of the isolated compounds were confirmed by FTIR and 1H NMR. Additionally, the significant fungistatic activity of betulin towards some fi lamentous fungi was deter…
Chemical and antifungal investigations of six Lippia species (Verbenaceae) from Brazil
2012
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Bioactive Steroidal Saponins from Smilax medica
2006
Two new spirostanol saponins ( 1 and 2) were isolated from the roots of Smilax medica, together with the known smilagenin 3-O-beta-D-glucopyranoside (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR experiments. Compounds 1 and 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs between 6.25 and 50 microg/mL) whereas 3 was inactive.
Antifungal activity of the carrot seed oil and its major sesquiterpene compounds.
2005
Carrot seed oil is the source of the carotane sesquiterpenes carotol, daucol and β-caryophyllene. These sesquiterpenic allelochemicals were evaluated against Alternaria alternata isolated from the surface of carrot seeds cultivar Perfekcja, a variety widely distributed in horticultural practise in Poland. Alternaria alternata is one of the most popular phytotoxic fungi infesting the carrot plant. The strongest antifungal activity was observed for the main constituent of carrot seed oil, carotol, which inhibited the radial growth of fungi by 65% at the following concentration.
Steroidal saponins from the roots of Smilax aspera subsp. mauritanica
2008
Two new steroidal saponins (1, 2) were isolated from the roots of Smilax aspera subsp. mauritanica (POIR.) ARCANG. (Liliaceae), together with the known curillin G (3), asparagoside E (4), asparoside A (5), asparoside B (6) and the phenolic compound resveratrol (7). Their structures were established mainly on the basis of 600 MHz 2D-NMR spectral data. 3 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (minimum inhibitory concentrations of 25, 25 and 50 microg/ml, respectively) whereas the other compounds were inactive.
Migration of Leukocytes into Filters Coated Homogeneously with Immune Complexes, Antigens, Lectins or Tripeptides
1980
Cellulose nitrate filters were incubated in solutions of albumin, a chemotactically active tripeptide (f-Met-Leu-Phe), immune complexes or lectins and afterwards washed with buffer. They showed a dose-dependent increased leukocyte migration, when tested in typical Boyden chambers in comparison to filters treated only with buffer. The tripeptide, the immune complexes and the lectins were stimulatory at very low concentrations and acted inhibitory at high concentrations. Treating filters with formaldehyde or glutardialdehyde had no clear stimulatory effect. These findings extend earlier observations obtained with casein. They show that cells move very effectively on solid substrata in the abs…
Components of an antigen-/T cell receptor-independent pathway of lymphokine production
1991
The general way to induce the synthesis of lymphokines by T cells is the stimulation through the T cell receptor (TcR) complex which results in an increase of intracellular [Ca2+] and in the activation of a tyrosine kinase as well as of protein kinase C. Lymphokine production induced via the TcR is inhibited by the immunosuppressive drug cyclosporin A (CsA). However, an alternative pathway of lymphokine production exists. Several T lymphocyte clones can synthesize interferon-gamma (IFN-gamma), granulocyte-monocyte colony-stimulating factor, and small amounts of interleukin (IL3) when stimulated with syngeneic or allogeneic accessory cells (AC) plus IL2. In contrast to the TcR pathway the al…
Alternative pathway activation of T cells by binding of CD2 to its cell-surface ligand.
1987
Activation of resting T lymphocytes is initiated by the interaction of cell-surface receptors with their corresponding ligands. In addition to activation through the CD3 (T3)-Ti antigen-receptor complex1, recent experiments have demonstrated induction of T-cell proliferation through the CD2 (T11) molecule2–4, traditionally known as the erythrocyte(E)-receptor, through which T cells can bind red blood cells (RBC)5–7. This 'alternative pathway' of T-cell activation2 was observed in vitro in response to combinations of anti-CD2 monoclonal antibodies (mAbs) that bind to distinct epitopes of CD2, such as mAbs against T112 plus T113 (ref. 2). The physiological importance of this activation pathwa…