Effect of some nickel compounds on red blood cell characteristics

The effect of certain inorganic and coordinated nickel compounds on the resistance to different destructive substances, rheological properties, and functional activity of healthy human red blood cells (RBC), was investigated. It is shown that nickel compounds affect the erythrocyte membrane lipid bilayer, as well as membrane proteins to various extents, depending on the type of compounds used. In general, the acceleration of erythrocyte aging was observed to be more pronounced in young erythrocytes. The observed results suggest that nickel compounds decrease water permeability across erythrocyte membranes. Almost all the investigated nickel compounds decrease erythrocyte thermostability, deformability, and the rate of O₂ release by erythrocytes.     

Purine and pyridine nucleotides in rabbit red blood cells of different maturity

Using reversed-phase high-performance liquid chromatography purine nucleotides, nucleosides and nucleobases as well as pyridine nucleotides were determined in extracts of reticulocytes and mature red blood cells of rabbits. The concentrations of almost all compounds measured decrease during the last phase of red blood cell maturation. These changes were interpreted with respect to the loss of mitochondria, accompanied by shifting the energy production from the preferentially oxidative mode to the exclusively glycolytic one and variations in the concentrations of purine compounds in blood plasma during reticulocytosis.     

Phenolic compounds and antioxidant activity from red grape marc extracts

The aims of this work were to determine the amounts of the different classes of phenolic compounds in an ethanolic extract from red grape marc and its components, peels and seeds, and to evaluate their antioxidant activities by the beta-carotene bleaching test for their utilization as natural antioxidants. The results showed that red grape marc was rich in polyphenol compounds with a clear antioxidant activity. The extracts, in fact, at very low concentration (20 ppm) in total phenols showed an antioxidant activity (AA) higher than 43% on average, while at higher concentration (80-160 ppm) all the fractions had an AA comparable to that of butlylated-hydroxytoluene. Grape seeds seemed to give the highest contribution to such AA, as they contained high quantities of proanthocyanidines, a type of flavonoid known for its high antioxidant properties.     

Effect of carbonyl compounds on red blood cells deformability

The effect of Maillard reaction on red blood cells (RBC) deformability was investigated. Exposure of RBC to carbonyl compounds (dl-glyceraldehyde, glyoxal, glycolaldehyde, 3-deoxyglucosone, and d-glucose) leading to Maillard reaction caused a marked decrease in RBC deformability even at 1 mM level. The decrease rate depended on the kind of carbonyl compounds, in which both dl-glyceraldehyde and glyoxal significantly decreased the RBC deformability (p < 0.05). In addition, the decrease rate also differed among volunteers tested, indicating that the sensitivity against carbonyl compounds varies among them. In order to elucidate the mechanism of the decrease in RBC deformability, RBC was exposed to carbonyl compounds in the presence of aminoguanidine which is the inhibitor of AGE formation in Maillard reactions. Aminoguanidine inhibited the decrease in RBC deformability by dl-glyceraldehyde and glyoxal. When Hb which has a high reactivity with carbonyl compounds was incubated with those carbonyl compounds, dl-glyceraldehyde and glyoxal showed the high reactivity with Hb compared with other carbonyl compounds. These results indicate that Maillard reaction between RBC proteins and carbonyl compounds leads to the decrease in RBC deformability. On the other hand, generated by carbonyl compounds involved in lowering the deformability only to a negligible level.     

6a-hydroxypterocarpans from red clover

Pisatin and homopisatin have been identified as antifungal compounds in red clover infected with either Botrytis cinerea, a non-pathogen, or Sclerotinia trifoliorum a clover pathogen. In addition 6a- hydroxymaackiain and 6a-hydroxymedicarpin have been detected. In vitro experiments have established that Sclerotinia can convert both maackiain and medicarpin to their respective 6a-hydroxylated products.     

Effect of metabolic inhibitors on formed novocaine and neutral red segregation zones in frog erythrocytes

Effects of some metabolic inhibitors, as well as of biologically active compounds (diakarb, ethidium bromide and a phenanthridine alkaloid sanguinarine) on the formed novocaine and neutral red segregation zones were studied. The volume of granules diminished under the influence of a glycolytic inhibitor iodoacetate, uncouplers of oxidative phosphorylation (2,4-dinitrophenol and carbonyl cyanide trifluoromethoxyphenylhydrozone), and respiratory inhibitors (antimycin A and rotenone), as well as under the influence of cycloheximide - an inhibitor of protein synthesis. Diakarb, ethidium bromide or sanguinarine also provoked a regression of the segregation zones. It has been found that all these compounds are inhibitors of ATPase activity of the isolated segregation zones. A possible mechanism of volume decreasing in segregation zones under the influence of both the metabolic inhibitors and diakarb, ethidium bromide and sanguinarine is discussed.     

Identification and characterization of xanthone biosynthetic genes contributing to the vivid red coloration of red-flowered gentian

Cultivated Japanese gentians traditionally produce vivid blue flowers because of the accumulation of delphinidin-based polyacylated anthocyanins. However, recent breeding programs developed several red-flowered cultivars, but the underlying mechanism for this red coloration was unknown. Thus, we characterized the pigments responsible for the red coloration in these cultivars. A high-performance liquid chromatography with photodiode array analysis revealed the presence of phenolic compounds, including flavones and xanthones, as well as the accumulation of colored cyanidin-based anthocyanins. The chemical structures of two xanthone compounds contributing to the coloration of red-flowered gentian petals were determined by mass spectrometry and nuclear magnetic resonance spectroscopy. The compounds were identified as norathyriol 6-O-glucoside (i.e., tripteroside designated as Xt1) and a previously unreported norathyriol-6-O-(6′-O-malonyl)-glucoside (designated Xt2). The copigmentation effects of these compounds on cyanidin 3-O-glucoside were detected in vitro. Additionally, an RNA sequencing analysis was performed to identify the cDNAs encoding the enzymes involved in the biosynthesis of these xanthones. Recombinant proteins encoded by the candidate genes were produced in a wheat germ cell-free protein expression system and assayed. We determined that a UDP-glucose-dependent glucosyltransferase (StrGT9) catalyzes the transfer of a glucose moiety to norathyriol, a xanthone aglycone, to produce Xt1, which is converted to Xt2 by a malonyltransferase (StrAT2). An analysis of the progeny lines suggested that the accumulation of Xt2 contributes to the vivid red coloration of gentian flowers. Our data indicate that StrGT9 and StrAT2 help mediate xanthone biosynthesis and contribute to the coloration of red-flowered gentians via copigmentation effects.     

Inhibition of angiogenesis and inflammation by an extract of red clover (Trifolium pratense L.)

Antiangiogenic compounds are gaining more and more interest as a new approach in the prevention and treatment of cancer and inflammatory diseases. The objective of this study was the evaluation of the antiangiogenic effect of a red clover extract (RCE) used in food supplements for menopausal complaints as well as of its main isoflavones in an in vivo system, the chorioallantoic membrane assay of fertilized hen's eggs. At a dosage of 250 μg/pellet the red clover extract showed excellent inhibition of angiogenesis. The antiangiogenic activity of the non-methylated isoflavones daidzein and genistein was higher than that of the methylated compounds formononentin and biochanin A. The results demonstrate that RCE is not only suitable for menopausal complaints, but might also be a powerful chemopreventive agent against chronic diseases e.g. which have a high incidence especially in elderly female.     

Effects of membrane partitioning and other physical chemical properties on the apparent potency of "membrane active" compounds evaluated using red blood cell lysis assays

The membrane-destabilizing properties of Amphotericin B and Zwittergent were used as benchmark compounds for examining in detail their membrane-altering effects in a series of human red blood cell lysis assays. The procedures included examining dose responses and the effects of different cell concentrations on potency in rbc lysis assays. In order to enhance detection of subtle membrane effects, we also used a range of NaCl concentrations to osmotically stress the rbc's. Using the benchmark compounds, a set of conditions was developed for examination of subtle membrane effects that may be applied to series of compounds with suspected membrane-perturbation activity. A group of experiments was defined that allow detection of the most important membrane-modifying behaviors among a diverse group of compounds. From an initial screen of bacterial growth inhibition over 150 compounds were examined for membrane-altering properties using the limited experimental protocols developed from the benchmark compounds. Several dose-response patterns were observed as useful for classifying compounds based on their tendency to alter membrane integrity and to partition into the lipids of membranes, as well as their propensity to form aggregates or precipitates. The methods may prove generally useful for distinguishing compounds whose primary activity is membrane destabilization from more interesting and useful pharmacological mechanisms of action.     

Inhibition of anion transport in the red blood cell membrane by anionic and non-anionic arginine-specific reagents

Arginine specific reagents are found to be powerful inhibitors of anion exchange in the red blood cell membrane. Some of these inhibitors such as cyclohexandione, phenylglyoxal and 2, 3-butandione are found to produce their inhibition by interacting covalently with band 3. In contrast to the action of these compounds, the inhibition caused by the phenylglyoxal derivative 4-hydroxy-3-nitrophenyl-glyoxal has been found to be completly reversible. In extending the studies on the mode of action of these compounds on sulfate exchange and to get some more information about their binding site, the degree of inhibition caused by different phenylglyoxal derivatives which have a similar core but differ in their substituent groups have been compared. The interaction between the binding sites of these compounds and other anion transport inhibitors have also been studied.     

Intestinal uptake of MPP+ is differently affected by red and white wine

It is becoming increasingly evident that ingested products, such as wine, may have profound effects on the therapeutic efficacy of certain drugs. As various xeno- and endobiotics are organic cations, the purpose of our study was to examine the modulation of organic cations intestinal apical uptake by red (RW) and white wine (WW). For this purpose, we used RW, WW, the same alcohol-free wines, phenolic compounds and ethanol. The uptake of the organic cation 1-methyl-4-phenylpyridinium (MPP+) was evaluated in Caco-2 cells, an intestinal epithelial cell model. RW and alcohol-free RW increased 3H-MPP+ apical uptake, although the effect of alcohol-free RW was less pronounced. On the other hand, WW and alcohol-free WW decreased the organic cation uptake but the effect of alcohol-free WW was more pronounced. Our results show that the total content in phenolic compounds was 7 times higher, and the dialysis index was about 4 times higher in RW compared to WW. Ethanol, in the same concentration found in wine, caused a significant decrease in 3H-MPP+ apical uptake. The solution containing high molecular weight compounds from dialyzed RW increased 3H-MPP+ apical uptake. In conclusion, the results suggest that RW may increase and WW may reduce the intestinal absorption of organic cations present in the diet, such as drugs or vitamins (e.g. thiamine and riboflavin). As ethanol alone decreased the uptake of MPP+, and alcohol-free RW and WW had a lower potency than intact wine upon the transport, the presence of ethanol is probably important for the solubilisation/bioavailability of the components endowed with the transport modulating activity.     

Dynamic superheated liquid extraction of anthocyanins and other phenolics from red grape skins of winemaking residues

Grape skins from a grape pomace were subject to extraction with superheated ethanol-water mixtures for quantitative extraction of anthocyans and other phenolic compounds. The variables affecting dynamic extraction of these compounds were studied and identification and quantification of the extracted compounds were performed by both direct spectrophotometry or after HPLC separation using UV or MS detectors. The optimal working conditions for total extraction of anthocyans were: 1:1 (v/v) ethanol-water acidified with 0.8% (v/v) HCl, 120 degrees C, 30 min, 1.2 ml/min and 80 bar. The yields of anthocyanins, total phenolics and flavanols thus obtained were much higher (3 times for anthocyanins, 7 times for total phenolics and 11 times for flavanols) than those provided by dynamic conventional solid-liquid extraction. Several sample preparation procedures for skins as alternatives to free-drying were also investigated and drying at 40 degrees C for 24h provided the best results. Extraction with acidified water provides similar composition and poorer efficiency than 1:1 ethanol-water; also similar to two commercial grape skin extracts used as natural colorants.     

Brominated anisoles and cresols in the red alga Polysiphonia sphaerocarpa

The red marine alga Polysiphonia sphaerocarpa was extracted by a simultaneous steam distillation-solvent extraction technique and several brominated compounds were identified by gas chromatography-mass spectrometry. The compounds detected were 2,4-dibromoanisole, 2,4,6-tribromoanisole, 3-bromocresol, 3,5-dibromocresol, 3-bromo-4-hydroxybenzaldehyde, 3,5-dibromo-4-hydroxybenzaldehyde, 2-bromophenol, 4-bromophenol, 2,4-dibromophenol, 2,6-dibromophenol and 2,4,6-tribromophenol. This is the first time brominated anisoles and cresols have been detected in marine algae.     

Inhibition of angiogenesis and inflammation by an extract of red clover (Trifolium pratense L.)

Antiangiogenic compounds are gaining more and more interest as a new approach in the prevention and treatment of cancer and inflammatory diseases. The objective of this study was the evaluation of the antiangiogenic effect of a red clover extract (RCE) used in food supplements for menopausal complaints as well as of its main isoflavones in an in vivo system, the chorioallantoic membrane assay of fertilized hen's eggs. At a dosage of 250 μg/pellet the red clover extract showed excellent inhibition of angiogenesis. The antiangiogenic activity of the non-methylated isoflavones daidzein and genistein was higher than that of the methylated compounds formononentin and biochanin A. The results demonstrate that RCE is not only suitable for menopausal complaints, but might also be a powerful chemopreventive agent against chronic diseases e.g. which have a high incidence especially in elderly female.     

Intra-cellular storage, transport and exocytosis of halogenated compounds in marine red alga Laurencia obtusa

The production of secondary metabolites in seaweed have been related to a capability to partition compounds into cellular specialized storage structures, like gland cells and the corps en cerise (CC) or cherry bodies. The possible mechanisms that bring these compounds to the thallus surface remain poorly understood. Therefore, the aim of this work is perform a characterization of the CC and determine the intra-cellular dynamics of halogenated compounds in Laurencia obtusa. The dynamics of CC and the mechanisms related to the intra-cellular transport of halogenated compounds were evaluated by using optical tweezers and time-lapse video microscopy. The CC were isolated and its elemental composition was characterized using X-ray microanalysis. The cellular distribution of halogenated compounds was also demonstrated by fluorescence microscopy. Three-dimensional reconstruction technique was used to provide a visualization of the structures that connect CC to cell periphery. As main findings, we confirmed that the halogenated compounds are mainly found in CC and also in vesicles distributed along the cytoplasm and within the chloroplasts. We demonstrated that CC is mechanically fixed to cell periphery by a stalk-like connection. A vesicle transport though membranous tubular connections was seen occurring from CC to cell wall region. We also demonstrated a process of cortical cell death event, resulting in degradation of CC. We suggested that the vesicle transportation along membranous tubular connections and cell death events are related to the mechanisms of halogenated compounds exudation to the thallus surface and consequently with defensive role against herbivores and fouling.     

Plocamium hamatum and its monoterpenes: chemical and biological investigations of the tropical marine red alga

The polyhalogenated monoterpene content of six samples of the tropical marine red alga Plocamium hamatum, collected from the southern, central and northern regions of The Great Barrier Reef, Australia, was assessed. In all but two of the samples, the polyhalogenated monoterpene content was shown to differ markedly. In total, eleven previously reported compounds were isolated and characterised (1-11). Compound 2 was obtained for the first time as a pure natural product. For compound 4 a single crystal X-ray crystallographic analysis was undertaken which established its absolute configuration as (1S,2S,4R,5R,1'E)-2-bromo-1- bromomethyl-1,4-dichloro-5-(2'-chloroethenyl)-5-methylcyclohexa ne. Complete and unambiguous 1H and 13C NMR data are reported for 2 and 4. For 6-8, some prior 13C NMR assignments are revised. The biological activities of compounds 2-8 and 11 were assessed and indicated 4 to have potent antialgal activity towards Chlorella fusca in an agar diffusion bioassay, as well as being moderately antitubercular and cytotoxic. Compound 6 demonstrated moderate cytotoxicity.     

Induction of clovamide by jasmonic acid in red clover

The effect of jasmonic acid (JA) on the secondary metabolism of 5-day-old red clover seedlings was investigated. Induction of the formation of four compounds was found in roots after treatment with 50 microM JA for 48 h, while no induction was observed in the shoots. These compounds, whose formation was induced by JA addition, were isolated and identified as caffeoyl DOPA (clovamide), caffeoyltyrosine, p-coumaroyl DOPA and p-coumaroyltyrosine, by ion-spray MS and 1H NMR analyses, and by chemical synthesis. Among them, clovamide was the most abundant, while the other amides represented only a minor portion. Clovamide started to increase in amount 24-36 h after treatment and reached a maximum after 96 h (2.81 nmol/mg fr. wt.). The induction of their formation was observed even with 5 microM of JA, and the amount increased with concentrations up to 100 microM. Treatment with 1 mM CuCl2, which elicits accumulation of the phytoalexin maackiain in red clover, caused a decrease in clovamide amount.     

Role of red carotenoids in photoprotection during winter acclimation in Buxus sempervirens leaves

The red leaf coloration of several plant species during autumn and winter is due to the synthesis of phenolic compounds such as anthocyanins or red carotenoids. The latter occur very rarely and are non-ubiquitous and taxonomically restricted compounds. The present study shows that the leaves of common box ( Buxus sempervirens L.) accumulate red carotenoids (eschscholtzxanthin, monoanhydroeschscholtzxanthin, anhydroeschscholtzxanthin) as a response to photoinhibitory conditions during winter acclimation. These compounds are produced in a coordinated manner with the operation of other photoprotective systems: accumulation and sustained deepoxidation of VAZ pigments with a concomitant decrease in maximal photochemical efficiency, accumulation of alpha-tocopherol and a gradual decrease on chlorophyll content. All these processes were reversed when the photosynthetic tissues were transferred from photoinhibitory winter conditions to room temperature for 9 days. Buxus leaves showed a large degree of phenotype variation in the degree of reddening, ranging from green to orange. The differences in colour pattern were mainly due to differences in the accumulation of red carotenoids and xanthophyll esters. Red pigments were mainly anhydroeschscholtzxanthin and esters of eschscholtzxanthin. Conversely to fruit or petal chromoplasts, the plastids of red leaves in this species are not the terminal differentiated state but are able to redifferentiate again to chloroplasts. Their photoprotective role during winter as a light screen system or as antioxidants, in a similar way to other red pigments, and their implications on the wide ecological tolerance of this evergreen species are discussed.     

Antibacterial bromophenols from the marine red alga Rhodomela confervoides

Two bromophenols, together with three known compounds, were isolated from the methanolic extract of the marine alga, Rhodomela confervoides. By means of MS and NMR spectroscopic analyses, they were identified as 3-bromo-4-[2,3-dibromo-4,5-dihydroxyphenyl] methyl-5-(hydroxymethyl) 1,2-benzenediol (1) and 3-bromo-4-[2,3-dibromo-4,5-dihydroxyphenyl] methyl-5- (ethoxymethyl) 1,2-benzenediol (2). Three known compounds were also isolated, namely 3-bromo-4-[2,3-dibromo-4,5-dihydroxyphenyl] methyl-5-(methoxymethyl) 1,2-benzenediol (3), 4,4'- methylenebis [5,6-dibromo-1,2-benzenediol] (4) and bis (2,3-dibromo-4,5-dihydroxybenzyl) ether (5). Compound 5 was the most active against five strains of bacteria with the MIC less than 70 microg/ml, while compounds 2, 3 and 4 exhibited moderate activity.     

Isolation and identification of antibacterial neo-compounds from the red ants of ChangBai Mountain, Tetramorium sp

Three novel coumarin compounds along with two known amide alkaloids were isolated from a methanol extract of the red ants of ChangBai Mountain, Tetramorium sp. Their structures were identified on the basis of IR, 2D NMR ((1)H-(1)H COSY, HSQC, HMBC and NOESY) and HRESIMS analysis. Antibacterial activity of all the compounds was evaluated using KB paper diffusion through measurement of inhibiting zone. It was found that four of all the compounds exhibited significant inhibitory activity against Gram-positive bacteria Bacillus subtilis with MIC values of 25 μg/ml (compounds 1-3) and 15 μg/ml (compound 4).