Anthraquinone Structure Research Articles

Antioxidant Phenolic Constituents in Roots of Rheum officinale and Rubia cordifolia: Structure−Radical Scavenging Activity Relationships

The phenolic constituents in the roots of Rheum officinale and Rubia cordifolia were identified with the aid of high-performance liquid chromatography and liquid chromatography-mass spectrometry and by comparison with authentic standards. A total of 17 hydroxyanthraquinones, gallic acid, and tannins were separated, and 14 of them were identified, being the main phenolic constituents present. Their antioxidant activity (Trolox equivalent antioxidant capacity) was evaluated using the improved 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt method. Hydroxyanthraquinones were the predominant antioxidant phenolic constituents in the roots of R. cordifolia, and tannins and gallic acid were the predominant antioxidant phenolic constituents in the roots of R. officinale. The structure-radical scavenging activity relationships of the tested hydroxyanthraquinones were systematically demonstrated as follows: Hydroxy groups on one benzene ring of the anthraquinone structure were essential for hydroxyanthraquinones to show activity, the ortho-dihydroxy structure in the hydroxyanthraquinone molecules could greatly enhance their radical scavenging effect, and glycosylation of the hydroxyanthraquinones reduced activity.

N-(3-Trifluoroethanesulfonyloxypropyl)anthraquinone- 2-carboxamide: a new heterobifunctional reagent for immobilization of biomolecules on a variety of polymer surfaces.

A new heterobifunctional reagent, N-(3-trifluoroethanesulfonyloxypropyl)anthraquinone-2-carboxamide (NTPAC) has been developed, useful for making bioconjugates and immobilization of biomolecules, viz., oligonucleotides, peptides, proteins, etc., on a variety of carbon-containing solid surfaces. Its trifluoroethanesulfonate ester group reacts with aminoalkyl or mercaptoalkyl functions present in biomolecules, and the anthraquinone structure reacts with a variety of carbon-containing polymers under ultraviolet irradiation (365 nm). The reagent has been used in two ways. First, the reagent, NTPAC, was first brought in contact with the above said supports and exposed to long wavelength ultraviolet light (365 nm), thereby generating active trifluoroethanesulfonate ester functions on the support, which subsequently react with appropriate mercaptoalkyl- or aminoalkyl-containing biomolecules to fix them on the supports. In another route, the proposed reagent was allowed to react first with proteins or 5'-aminoalkyl- or mercaptoalkyl-modified oligonucleotides to form the appropriate biomolecule-anthraquinone conjugate, which was then brought in contact with a variety of carbon-containing polymers, viz., modified controlled pore glass (CPG), modified glass microslides, cross-linked polystyrene, nylon, cross-linked polysaccharides, polypropylene (PP), polyethylene (PE), etc., and exposed to long wavelength ultraviolet light (365 nm), resulting in immobilization of the conjugates on the support. Both of the routes work satisfactorily and we could successfully immobilize a number of enzymes and modified oligonucleotides on a variety of supports.

Evaluation of hypersensitivity to anthraquinone-related substances.

Evaluation of hypersensitivity to anthraquinone dyes, which are widely used as color additives, was performed in guinea pigs. In animals sensitized with 1% commercial-grade D&C Green No. 6 (Quinizarin Green SS, CI61565), subsequent challenge with the same dye showed a dose-dependent hypersensitivity reaction, whereas challenge with D&C Green No. 6 purified by recrystallization did not. Guinea pigs sensitized with commercial-grade D&C Green No. 6 showed a positive reaction to challenge with quinizarin, an intermediate in dye synthesis, but not to p-toluidine, another intermediate. It was confirmed that quinizarin itself induced hypersensitivity. The cross-reactivity of four kinds of purified dyes, in which the quinizarin contents were 1.2ppm or less, was evaluated. Purified D&C Green No. 5 (Alizarin Cyanin Green F, CI61570), D&C Green No. 6 and Ext. D&C Violet No. 2 (Alizurol Purple, CI60730) did not produce a hypersensitivity response, while D&C Violet No. 2 (Alizurin Purple SS, CI60725) did. We found that D&C Green No. 5, D&C Green No. 6 and Ext. D&C Violet No. 2 do not intrinsically induce hypersensitivity, and we conclude that the reaction to challenge with the commercial-grade dyes is due to quinizarin contaminating them. In contrast, D&C Violet No. 2 per se induced hypersensitivity. A structure-activity study indicated that 1-hydroxyl and 4-hydroxyl groups in the anthraquinone structure are key factors in hypersensitivity induction by anthraquinone-related compounds.

By-products Formation during the Ozonation of the Reactive Dye Uniblu-A

The degradation by ozone of the hydrolyzed Uniblu-A (Uniblu-OH), i.e. the compound found in the spent bath resulting from dyeing process with the reactive dye Uniblu-A, has been studied with the aim of identifying intermediate as well as end by-products formed. The experimental results, obtained by ozonating (16 mg O3/L in the feed gas at 100 mL/min) aqueous solutions (500 ml) of Uniblu-OH (40 mg/L), in the presence or not of t-butanol, show that the oxy-dye is completely removed within 30 minutes and that its decay results only slightly affected by the presence of t-butanol. Several organic by-products have been identified by liquid chromatography-mass spectrometry (turboionspray interface) as a result of the oxy-dye degradation. Such by-products result from oxidation of the amino group, hydroxylation of the aromatic rings, cleavage of the alkyl chain, cleavage of the sulfoalkylbenzene group leaving substituted anthraquinone structures and cleavage of the latter structures leading to phthalic acid. Such by-products are further degraded leading to the formation of low molecular weight aldehydes and acids, nitrate and sulphate. As for the formation of inorganic end by-products, after 120 minutes of ozonation, the percentages of nitrate and sulphate conversion resulted 6 and 7 %, 53 and 89% in the absence and in the presence of t-butanol respectively.

Synthesis and application of polymeric dyes containing the anthraquinone structure

Two polymeric dyes containing the anthraquinone structure were prepared via solution polycondensation. Their monomers were prepared through reactions between 1,5-dichloroanthraquinone and nucleophiles. The polymeric dyes were characterized with NMR and thermogravimetry. Their ultraviolet spectra, intrinsic viscosity, and solubility were also measured. Then, the polymeric dyes were applied to the mass coloration of poly(ethylene terephthalate) with good compatibility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1252–1257, 2002

Synthesis of polyetherurethane cationomers with anthraquinone structure

An anthraquinone monomer, 1,4-bis-(β)-iodopropionyloxy)-9,10-anthraquinone was obtained by the condensation of 1,4-dihydroxy-9,10-anthraquinone with β-chloropropionyl-chloride, followed by an exchange reaction with potassium iodide in the presence of acetone. This derivative was used to synthesize polyetherurethane cationomers by two-step Menschutkin reaction. The resulting ionenes had ammonium quaternary groups content between 98.8 and 149.6 meq/100 g polymer and the quantity of anthraquinone units in polymeric chains was between 29.8 and 45.2 wt.% polymer, respectively. The tensile and thermal properties are similar to other elastomeric polyurethanes.These anthraquinone polyurethane colorants could be useful for coloring a wide variety of products such as fibers, films, coatings, paints or inks.

2-(1-Oxyalkyl)-1,4-dioxy-9,10-anthraquinones: synthesis and evaluation of antitumor activity.

Fourty eight derivatives of 2-(1-oxyalkyl)-1,4-dioxy-9,10-anthraquinone were synthesized, and their antitumor activity was evaluated. On the whole, 2-(1-hydroxyalkyl)-1,4-dihydroxy-9,10-anthraquinones (DHAQ = 1,4-dihydroxy-9,10-anthraquinone) showed stronger cytotoxic activity against L1210 cells than 2-(1-hydroxyalkyl)-1,4-dimethoxy-9,10-anthraquinones(DMAQ = 1,4-dimethoxy-9,10-anthraquinone), implying that free hydroxy groups at C-1 and C-4 of the anthraquinone structure are necessary for the cytotoxic activity. The bioactivity of 2-(1-hydroxyalkyl)-DHAQ derivatives differed according to the size of alkyl group at C-1; while the elongation of alkyl group over 7 carbon atoms failed to enhance the bioactivity, the derivatives possessing alkyl moiety of 1-6 carbon atoms showed an increase in the cytotoxicity and the antitumor activity in Sarcoma-180; 2-hydroxymethyl-DHAQ (ED50, 15 micrograms/ml; T/C, 125%), 2-(1-hydroxyethyl)-DHAQ(1.9 micrograms/ml; 139.2%), 2-(1-hydroxypropyl)-DHAQ (7.2 micrograms/ml; 135.1%), 2-(1-hydroxybutyl)-DHAQ (10.2 micrograms/ml; 125.3%), 2-(1-hydroxypentyl)-DHAQ (23.7 micrograms/ml; 110.1%), and 2-(1-hydroxyhexyl)-DHAQ (58 micrograms/ml; 108%). Next, 2-(1-Hydroxyalkyl)-DHAQ derivatives were acetylated to produce 2-(1-acetoxyalkyl)-DHAQ analogues. Although the acetylation somewhat enhanced the cytotoxicity, but not the antitumor action. In addition, the presence of phenyl group at C-1' enhanced the cytotoxicity and the T/C value, compared to alkyl groups of same size; 2-(1-hydroxy-1-phenyl)-DHAQ (ED50, 5.6 micrograms/ml; T/C, 137%).

Antiviral activities of anthraquinones, bianthrones and hypericin derivatives from lichens.

The antiviral activities of some naturally occurring anthraquinones, bianthrones, and hypericin derivatives were compared by the end-point CPE (viral cytopathic effects) method and plaque assays. Under optimal conditions of exposure to light, hypericin, 7,7'-dichlorohypericin and 5,7-dichloroemodin exhibited strong inhibitory activity against HSV-1 (herpes simplex virus type 1) in both assays. Partial inactivation of the virus was shown by emodin, 7-chloroemodin and 7-chloro-1-O-methylemodin; the bianthrones and other anthraquinones were found to be inactive. Antiviral activity appeared to be positively correlated with increasing substitution of chlorine in the anthraquinone structure. In the absence of light, only hypericin and 7,7'-dichlorohypericin displayed detectable activity.

Spectrophotometric Determination of Acidity Constants of Some Anthraquinone Derivatives in Binary Methanol-Water Mixtures

A spectrophotometric method was used to determine the acidity constants of some synthetic derivatives of 1-hydroxy-9,10-anthraquinone in binary methanol-water mixtures at 25°C. A linear inverse relationship is observed between pKa of all acids and the mole fraction of methanol in the solvent mixtures. The influence of the nature and position of substituents in the molecular structure of anthraquinone on the ionization constants is discussed.

Structure-activity relationships of anthraquinones as inhibitors of 7-ethoxycoumarin O-deethylase and mutagenicity of 2-amino-3-methylimidazo[4,5- f]quinoline

The antimutagenicity of 17 natural and synthetic anthraquinones was determined using Salmonella typhimurium TA98 against 2-amino-3-methylimidazo[4,5- f]quinoline (IQ) in the presence of Aroclor 1254-induced rat hepatic S9. In general, the relationship between the chemical structures of anthraquinones and their antimutagenicity was found to contain one or more of the following features: (i) C9 carbonyl group, (ii) hydroxyl group at C1 and C4, (iii) C2 ethyl group, and (iv) C3 methyl group. The inhibitory effect of anthraquinones on 7-ethoxycoumarin O-deethylase (ECD) of Aroclor 1254-induced hepatic microsomes was also examined. In addition, we studied the effect of anthraquinones on the metabolism of IQ by Aroclor 1254-induced microsomes using high-performance liquid chromatography. The antimutagenicity correlated with the inhibition of cytochrome P-450IA2-linked ECD activity in hepatic microsomes, and with the inhibition of N-hydroxy-IQ formation of IQ metabolism by hepatic microsomes. Moreover, we also examined the antimutagenicity of anthraquinones against synthetic N-hydroxy-IQ. Quinizarin and anthraflavic acid were shown to have more effect on the direct mutagenicity of N-hydroxy-IQ than that of the anthraquinones tested. This might explain why both anthraquinones showed higher antimutagenicity, although they inhibited ECD less. These results suggest that there exist at least two mechanisms of action in modifying roles of anthraquinones on the mutagenicity of IQ: (i) mediation through interaction with microsomal activating enzymes to inhibit the major active metabolite of N-hydroxy-IQ formation and (ii) direct interaction with the proximate metabolite of IQ, N-hydroxy-IQ, to block its attack on DNA.

Paeciloquinones A, B, C, D, E and F: new potent inhibitors of protein tyrosine kinase produced by Paecilomyces carneus. II. Characterization and structure determination.

Paeciloquinones A to F and versiconol have been isolated as inhibitors of protein tyrosine kinases from the culture broth of the fungus Paecilomyces carneus P-177. The structures of the new anthraquinones were determined by spectroscopic methods, mainly 1H NMR and 13C NMR. The substitution pattern was established by investigation of the respective methylated derivatives.

MONOCLONAL-ANTIBODY AGAINST DOXORUBICIN (DXR) - SOME CHARACTERISTICS AND UTILIZATION FOR DXR-IMMUNOASSAY

To establish a rapid, specific, sensitive and simple assay method for doxorubicin (DXR) in body fluid, monoclonal antibodies (MAbs) against DXR were generated by immunizing mice with keyhole limpet hemocyanin-DXR conjugate, cell fusion, and a one step, time saving screening ELISA method using aminoplate-coupled DXR via a glutaraldehyde bridge as solid phase antigen. Inhibition ELISA for DXR-immunoassay was established using anti-DXR MAb of the best producer (2E9) and aminoplate-coupled DXR as antigen and DXR ranging from 50 pg to 50 ng in the body fluid or in the cell extract could be detected. MAb 2E9 cross-reacted to various degrees to anthracycline compounds, such as some DXR analogues and derivatives, but did not recognize anthracene and anthraquinone structures.

Monoclonal antibodies against doxorubicin.

Hybridomas which secrete monoclonal antibodies (MAbs) reacting with doxorubicin (DXR), a widely used anthracycline cytotoxic antibiotic, have been obtained by fusing NSO/P3 mouse myeloma cells with spleen cells from BALB/c mice immunized with DXR-BSA conjugate. The best producer among the several clones obtained was expanded and the secreted MAb (MAD2) purified and characterized. MAD2 cross-reacts to varying degrees with anthracycline compounds such as some DXR analogues and derivatives, but does not recognize anthracene and anthraquinone structures, with the exception of weakly reacting Mitoxantrone. MAD2 and the panel of MAbs which are at present being purified may become a tool for studying the relevance of different domains of the anthracyclin molecule in terms of biologic activity.

EPR and UV-visible spectroscopic studies of copper(II) and cobalt(II) complexes of hydroxyanthraquinones

Interactions of 1-hydroxyanthraquinone (1-HAQ) and 1,4- and 1,8-dihydroxyanthraquinone (1,4-DHAQ, 1,8-DHAQ) with Co 2+ and Cu 2+ have been examined by UV-visible and EPR spectroscopies. These hydroxyanthraquinones form high-spin complexes with Co 2+. It has been estimated that these Co 2+ complexes in dichloromethane and ethanol have a tetragonal coordination structure, while in dimethlyformamide (DMF) or in mixed solvents containing DMF the complex having a tetrahedral structure is simultaneously formed. 1-HAQ forms the ML and ML 2 type complexes with Cu 2+, their relative concentration depending on the ligand to metal mole ratio, R, in solution. 1,4-DHAQ forms also the ML 2 type complex with Cu 2+, but the ML-type mononuclear Cu 2+ complex was not directly detected by EPR, though 1,4-DHAQ was estimated to form a polymer-type complex with Cu 2+ having metal-ligand ratio of ~ 1:1. For the case of 1,8-DHAQ, the formation of S = 1 M 2L 2-type dinuclear complex was observed, in addition to the formation of ML- and ML 2-type complexes. The ML 2-type Cu 2+ complexes of 1,4- and 1,8-DHAQ were found to have two forms, the cis and trans configurations. These properties for metal complex formation of the hydroxyanthraquinones are compared with those of adriamycin, which has a similar anthraquinone structure in the molecule.

Relationship of chemical structures of anthraquinones with their effects on the suppression of immune responses

A series of 37 anthraquinones were evaluated for their ability to inhibit the induction of cytolytic T-lymphocytes in a mixed lymphocyte culture system, useful as a preliminary screen for immunosuppressive agents. These compounds were also tested for their ability to prevent the production of antibody in mice. It was demonstrated that 1,4- bis [(2-aminoethyl)amino]-5, 8-dihydroxy-9,10-anthracenedione dihydrochloride (AEAD, 2) derived from mitoxantrone (MX, 1) by removing hydroxyethyl groups from both side chains was extremely active in depressing immune responses in vitro and in vivo. Four additional anthraquinones related to AEAD were also identified to share similar suppressive activity. They include a Schiff base, 1,4-dihydroxy-5,8- bis[[2-[3-pyridinylmethylene)amino]ethyl]amino]-9,10-antracenedione ( 25); a dimer with N-terminals methylated, 1,1-[ethylenebis (iminoethyleneimino)]- bis[5,8-dihydroxy-4-[(2-methylamino-ethyl)amino] anthraquinone tetrahydrochloride (35); an oxazolidine, 1,4-dihydroxy-5,8- dis [[2-(2-propyl-3-oxazolidinyl)ethyl]amino] anthraquinone (10); and its polymeric oxazolidine, poly [5,8-dihydroxy-1,4-anthraquinonyleneiminoethylene-3,2-oxazolidine-diyltrimethylene-2,3-oxazolidinediylethyleneimino] (36). These compounds may warrant further consideration as candidates for the treatment of refractory autoimmune diseases and in organ transplantation.

Molecular-packing analysis of some naphthaquinone and anthraquinone structures. The crystal structure of 2-methyl-5,8-dihydroxy-1,4-naphthaquinone

Molecular-packing analysis of some naphthaquinone and anthraquinone structures. The crystal structure of 2-methyl-5,8-dihydroxy-1,4-naphthaquinone

Structure and biosynthesis of a new anthraquinone from Streptocarpus dunnii

A new anthraquinone (1-hydroxy-2-hydroxymethylanthraquinone has been isolated from the title plant. The structure was determined by spectroscopy and synthesis. Investigation on the biosynthesis showed that this quinone is formed via o-succinoylbenzoic acid.

Contributions to organic spot test analysis

Along with the discussion of their chemical background descriptions have been given of: 1. Detection of hexamine through pyrohydrolytic splitting, which leads to formaldehyde and ammonia. 2. Detection of hexamine through sintering with ammonium chloride whereby volatile aliphatic amines result. 3. Detection of hexamine through pyrooxidation with benzoyl peroxide or lead dioxide with production of formaldehyde and ammonia. 4. Detection of benzoyl peroxide through pyrooxidation of hexamine with production of formaldehyde. 5. Detection of triphenylphosphine (-arsine, -stibine, -bismuthine) through formation of polyiodides. 6. Detection of mucic acid through pyroammonolytic formation of pyrrole. 7. Detection of salts of cyclohexylsulfamic acid through formation of sulfate in deamination with nitrous acid. 8. Detection of hippuric acid and derivatives through pyrohydrolytic formation of glycine. 9. Detection of anthraquinone and nuclear-substituted derivatives by reduction to red anthrahydroquinones with sodium hydrosulfite. 10. Detection of dyestuffs with anthraquinone structure through reduction by hydrosulfite with production of anthrahydroqinone derivatives.

Refinement of the structure of anthraquinone

Refinement of the structure of anthraquinone

Correlation between Colorfastness and Structure of Anthraquinone Blue Disperse Dyes

A correlation is estahlished between the structure of blue amino anthraquinone dyes for cellulose acetate, cellulose triacetate, and the polyester fibers and the colorfastness they exhibit towards the atmospheric agents responsible for gas and ozone fading and towards the action of light. Any structural modification which reduces the electron density on the amino nitrogen attached to the anthraquinone ring, whether it is an amino, an alkylamino, or an arylamino nitrogen, will increase the resistance of the molecule to the electrophilic agents responsible for the chemical changes which occur during fading. Several anthraquinone structures with improved resistance to fading are reported. These contain, as substituents on the arylamino radical, groups which withdraw electrons from the aromatic ring, leaving the amino nitrogen with a low electron density.