Search results for "alternative"

Chemical composition of the essential oil of the local endemics Centaurea davidovii and C. parilica (Asteraceae, sect. Lepteranthus) from Bulgaria

2014

In the present study the chemical compositions of the essential oils from aerial parts of Centaurea davidovii Urum. and C. parilica Stoj. & Stef., both endemic to Bulgaria, were evaluated by GC and GC-MS. The main components of C. davidovii were β-eudesmol (13.9%), spathulenol (13.3%), caryophyllene oxide (10.1%) and ( Z)-phytol (5.4%). The main components of C parilica were hexadecanoic acid (39.2%), ( Z, Z)-9,12-octadecadienoic acid (11.9%), caryophyllene oxide (6.8%) and spathulenol (6.6%). In order to compare the essential oils composition of these taxa and of related species a PCA analysis was carried out.

Impact of Ultrabithorax alternative splicing on Drosophila embryonic nervous system development.

2015

Hox genes control divergent segment identities along the anteroposterior body axis of bilateral animals by regulating a large number of processes in a cell context-specific manner. How Hox proteins achieve this functional diversity is a long-standing question in developmental biology. In this study we investigate the role of alternative splicing in functional specificity of the Drosophila Hox gene Ultrabithorax (Ubx). We focus specifically on the embryonic central nervous system (CNS) and provide a description of temporal expression patterns of three major Ubx isoforms during development of this tissue. These analyses imply distinct functions for individual isoforms in different stages of n…

Cytotoxicity of two naturally occurring flavonoids (dorsmanin F and poinsettifolin B) towards multi-factorial drug-resistant cancer cells.

2015

Abstract Introduction The expression of diverse resistance mechanisms in cancer cells is one of the major barriers to successful cancer chemotherapy. Methods In the present study, we assessed the cytotoxicity of two naturally occurring flavonoids dorsmanin F ( 1 , a flavanone) and poinsettifolin B ( 2 , a chalcone) against 9 drug-sensitive and multidrug-resistant (MDR) cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these compounds, whilst caspase-Glo assay was used to detect caspase activation. Cell cycle, mitochondrial membrane potential (MMP) and levels of reactive oxygen species (ROS) were all analysed via flow cytometry. Results Compounds 1 and…

Cytotoxicity and modes of action of 4'-hydroxy-2',6'-dimethoxychalcone and other flavonoids toward drug-sensitive and multidrug-resistant cancer cell…

2014

Abstract Introduction Resistance of cancer to chemotherapy is a main cause in treatment failure. Naturally occurring chalcones possess a wide range of biological activities including anti-cancer effects. In this work, we evaluated the antiproliferative activity of three chalcones [4′-hydroxy-2′,6′-dimethoxychalcone ( 1 ), cardamomin ( 2 ), 2′,4′-dihydroxy-3′,6′-dimethoxychalcone ( 3 )], and four flavanones [( S )-(–)-pinostrobin ( 4 ), ( S )-(–)-onysilin ( 5 ) and alpinetin ( 6 )] toward nine cancer cell lines amongst which were multidrug resistant (MDR) types. Methods The resazurin reduction assay was used to detect the antiproliferative activity of the studied samples whilst flow cytometr…

Cytotoxicity of three naturally occurring flavonoid derived compounds (artocarpesin, cycloartocarpesin and isobavachalcone) towards multi-factorial d…

2015

Abstract Introduction Cancer remains an aggressive deadly disease, if drug resistance develops. This problem is aggravated by the fact that multiple rather than single mechanisms are involved in resistance and that multidrug resistance (MDR) phenomena cause inefficacy of many clinical established anticancer drugs. We are seeking for novel cytotoxic phytochemicals to combat drug-resistant tumour cells. Methods In the present study, we investigated the cytotoxicity of three naturally occurring flavonoids including two flavones artocarpesin (1) and cycloartocarpesin (2) and one chalcone, isobavachalcone (3) against 9 drug-sensitive and MDR cancer cell lines. The resazurin reduction assay was u…

Junceosides A-C, new triterpene saponins from Arenaria juncea.

2002

Three novel triterpenoid saponins, junceosides A (1), B (2), and C (3), together with two known saponins have been isolated from the roots of Arenaria juncea. Their structures were elucidated using a combination of homo- and heteronuclear 2D NMR techniques (COSY, TOCSY, NOESY, HSQC, and HMBC) and by FABMS. The new compounds were characterized as 3-O-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-galactopyranosyl-(1-->3)]-beta-D-glucuronopyranosylgypsogenin-28-O-beta-D-glucopyranosyl(1-->3)-[beta-D-xylopyranosyl-(1-->4)]-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranoside (1), 3-O-alpha-L-arabinopyranosyl-(1-->2)-[beta-D-galactopyranosyl-(1-->3)]-beta-D-glucuronopyranosylgypsogenin-28-O-beta-D-x…

Hypolaetin-8-O-Glucoside, An Anti-inflammatory Flavonoid from Sideritis mugronensis.

1985

Methods of in vitro toxicology

2002

In vitro methods are common and widely used for screening and ranking chemicals, and have also been taken into account sporadically for risk assessment purposes in the case of food additives. However, the range of food-associated compounds amenable to in vitro toxicology is considered much broader, comprising not only natural ingredients, including those from food preparation, but also compounds formed endogenously after exposure, permissible/authorised chemicals including additives, residues, supplements, chemicals from processing and packaging and contaminants. A major promise of in vitro systems is to obtain mechanism-derived information that is considered pivotal for adequate risk asses…

Cytotoxic Spirostane-Type Saponins from the Roots of Chlorophytum borivilianum

2009

Four new spirostane-type saponins named borivilianosides E-H (1-4) were isolated from an ethanol extract of the roots of Chlorophytum borivilianum together with two known steroid saponins (5 and 6). The structures of 1-4 were elucidated using mainly 2D NMR spectroscopic techniques and mass spectrometry. The cytotoxicity of borivilianosides F (2), G (3), and H (4) and three known compounds was evaluated using two human colon cancer cell lines (HT-29 and HCT 116).

Studies on the mechanism of PMN activation. I. By dextran sulfates.

1982

Evidence is presented that enhanced reduction of the dye nitroblue-tetrazolium (NBT) by polymorphonuclear leukocytes (PMN) which are stimulated by dextran sulfates (DS) is not exclusively due to the phagocytosis of particles formed by NBT and DS. Not only the size of phagocytizable particles but the degree of substitution determines the acceleration of NBT-reduction. A likely cause of this acceleration is the triggering of the alternative pathway of the complement activation.