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PubMed2002

Mushroom tyrosinase inhibition activity of some chromones.

Currently, aloesin is used in the cosmetic industry as a whitening agent because it inhibits tyrosinase activity. Aloesin is a C-glycosylated chromone compound isolated from aloe, and it is difficult to synthesize because of C-glycosyl moiety in the molecule. The purpose of this study is to search for a new chromone compound which is easy to synthesize and which posesses stronger tyrosinase inhibitory activity than aloesin. Fourteen chromone derivatives were synthesized and screened for their mushroom-tyrosinase inhibitory activity. 5-Methyl-7-methoxy-2-(2'-benzyl-3'-oxobutyl)chromone (15) showed the strongest activity among tested compounds. Its activity was not only stronger than aloesin, but also stronger than arbutin and kojic acid. The kinetic analysis revealed a competitive inhibition of 15 with tyrosinase for the L-tyrosine binding site.

Agaricales↗
PubMed1990

[Studies on the chemical constituents of Aquilaria sinensis (Lour.) Gilg. V. Isolation and characterization of three 2-(2-phenylethyl) chromone derivatives].

Three 2-(2-phenylethyl) chromone derivatives were isolated from the ethyl acetate soluble fraction of the alcoholic extract of Aquilaria sinensis (Lous.) Gilg. (Thymeleaceae) by silica gel chromatography. Based on spectral data (UV, IR, 1HNMR, 13CNMR and MS) two of them are new compounds and their structures were identified as 5,8-dihydroxy-2-(2-p-methoxyphenylethyl) chromone (2) and 6,7-dimethoxy-2-(2-p-methoxyphenylethyl) chromone (3). The known compound siolated for the first time from this plant, was identified as 5,8-dihydroxy-2-(2-phenylethyl)-chromone (1).

Chemical Phenomena↗
PubMed1982

[Chemical and pharmacological research on pyran derivatives. XV. Phenyl-substituted 2-(dialkylamino)chromones].

Some 2-(dialkylamino)chromones phenyl substituted in position 6 or 7 or 8 were synthesized by reaction of N,N-dialkylethoxycarbonylacetamides with 4- or 3- or 2-biphenylol, respectively, in the presence of phosphorus oxychloride. The pharmacological activity of these compounds was then evaluated and compared with that shown by naphthopyran derivatives of structures (I), (II), and (III). With this same purpose also 6- and 8-benzyl derivatives of 2-(dialkylamino)chromones were prepared by using in the reaction 4- or 2-benzylphenol. Pharmacological screening showed that 6-phenyl substituted 2-(dialkylamino)chromones maintained the antireserpine and antimetrazole acti-activities which were possessed by the 1H-naphtho[2,1-b]pyran derivatives (I) and the 4H-naphtho[2,3-b]pyran derivatives (II), whereas 7-phenyl substituted compounds were devoid of any activity. 8-Phenyl substituted 2-(dialkylamino)chromones maintained to some extent the antiamphetamine activity which was clearly shown by the 4H-naphtho[1,2-]pyran derivatives (III). Furthermore, the compounds bearing the benzyl substituent both in the 6 or 8 position showed only antimetrazole activity.

Animals↗
PubMed2005

Aggregation behavior and chromonic liquid crystal properties of an anionic monoazo dye.

X-ray scattering and various optical techniques are utilized to study the aggregation process and chromonic liquid crystal phase of the anionic monoazo dye Sunset Yellow FCF. The x-ray results demonstrate that aggregation involves pi-pi stacking of the molecules into columns, with the columns undergoing a phase transition to an orientationally ordered chromonic liquid crystal phase at high dye concentration. Optical absorption measurements on dilute solutions reveal that the aggregation takes place at all concentrations, with the average aggregation number increasing with concentration. A simple theory based on the law of mass action and an isodesmic aggregation process is in excellent agreement with the experimental data and yields a value for the "bond" energy between molecules in an aggregate. Measurements of the birefringence and order parameter are also performed as a function of temperature in the chromonic liquid crystal phase. The agreement between these results and a more complicated theory of aggregation is quite reasonable. Overall, these results both confirm that the aggregation process for some dyes is isodesmic and provide a second example of a well-characterized chromonic system.

Journal Article↗
PubMed1984

Mutagenicity of flavones, chromones and acetophenones in Salmonella typhimurium. New structure-activity relationships.

28 flavones and 11 structurally-related flavonoids, chromones, and acetophenones, were tested for mutagenicity in the Salmonella typhimurium his reversion assay. 7 flavones, all of which were hydroxy- or methoxy-substituted at position 8, were moderate to strong mutagens in strain TA100 in the presence of rat liver S9 mix. In each case, the response of strain TA98 was either not significant or was very much weaker than that observed in strain TA100. The activation by S9 is not mediated by the microsomal cytochrome P450 system, since activation was not diminished when microsomes were removed by centrifugation at 100 000 X g. The observed strain specificity and structural requirements for activity indicate a mutagenic mechanism different from that associated with previously reported mutagenic flavonols (3-hydroxy-flavones) which are most active in strain TA98. The most mutagenic flavone investigated, 5,7,8-trihydroxy-flavone (norwogonin), had a potency of 17 revertants/nmole. Simplification of the chemical structures to hydroxy-substituted chromone and acetophenone systems revealed similar strain specificity, hydroxylation requirements, and S9 dependence within these structural classes, suggesting a similar activation pathway and mutagenic mechanism. The greatest mutagenic potency was observed within the flavone series, but significant potency was retained by similarly hydroxylated chromones and acetophenones. No mutagenic activity was observed in the absence of the aryl ketone moiety.

Acetophenones↗
PubMed2002

Chromatography of the chromone and flavonoid alkaloids.

TLC methods have been derived for the qualitative investigation of the small group of compounds known as chromone and flavonoid alkaloids. Quantitation of two of the chromone alkaloids has been achieved by HPLC and a graphite column has been used to separate the unstable stereoisomers of the piperidone chromone alkaloids. A variety of preparative methods, including silica column and droplet counter-current chromatography, has been used to isolate the members of this group of compounds from plant extracts.

Alkaloids↗
PubMed2002

Two chromones from Peperomia vulcanica.

TWO CHROMONES: 5-hydroxy-2-(14'-(E)-nonadecenyl) chromone (1) and 5-hydroxy-2-[12'-(3",4"-methylenedioxyphenyl)dodecanyl] chromone (2), together with six known compounds have been isolated from Peperomia vulcanica Baker & C. H. Wright (Piperaceae). Their structures were determined by spectroscopic analysis including 2D NMR techniques.

Chromones↗
PubMedDate not supplied

Microbiological transformation of chromone, chromanone, and ring A hydroxyflavones.

Microbial transformation of chromone, chromanone, and 3 ring A hydroxyflavones (5-hydroxy-, 6-hydroxy-, and 7-hydroxyflavones) was attempted using thirty-two microorganisms. While chromone was not biotransformed, chromanone was transformed to chromone and chromanol by Aspergillus niger in 2% yield. Ring A hydroxylated flavones were transformed to the corresponding C-4' hydroxylated metabolites, and the yields and rate of product formation were found to correlate with the distance between the C-4 carbonyl group and the hydroxyl group in ring A.

Bacteria↗
PubMed2001

New 2-(2-phenylethyl) chromones from Bothriochloa ischaemum.

Two new 2-(2-Phenylethyl) chromones were isolated from Bothriochloha ischaemum (Gramineae). They were characterized as 5-hydroxy-6-methoxy-2-[2-(2-hydroxyphenyl)-ethyl]-chromone(1) and 5-hydroxy-2-[2-(2-hydroxyphenyl)-ethyl]-chromone(2) by means of spectroscopic analysis, especially 2D-NMR experiments.

China↗
PubMed1999

Interaction of oligonucleotides conjugated to substituted chromones and coumarins with HIV-1 reverse transcriptase.

Ten different pyranone-related substituents (chromones or coumarins) were covalently linked to the 5' end of various oligonucleotides (ODN). The interaction of these compounds with human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) was analyzed. A different behavior was found to depend on the structure of the oligonucleotide derivatives. Some compounds activated the enzyme at relatively low concentrations (0.1-0.5 microM), followed by an inhibition of the activity at higher concentrations (5-20 microM), whereas others behave just as inhibitors. Because the presence of some coumarin or chromone derivatives conjugated to ODNs enhanced the interaction with the reverse transcriptase, we analyzed the capacity of such ODN derivatives to be used as primers. The introduction of substituent I, a chromone derivative, the 2-[(3-(aminopropyl)amino]-8-isopropyl-5-methyl-4-oxo-4H-1-benzopyran-3-c arbaldehyde], and II, a coumarin derivative, the 1-(3-aminopropoxy)-2-ethyl-3H-naphto[2,1-b]pyran-3-one, into the 5' end of a noncomplementary ODN allowed these compounds to be used as primers. In the case of complementary primers, the presence of conjugated derivatives enhanced the affinity with Km values that were two to three orders of magnitude lower than that of a complementary primer of the same length. After addition of a ddT-unit to the 3'-terminal end of the ODN, some of these primers became very effective inhibitors of RT with Ki values in the nanomolar range.

Chromones↗
PubMed2002

New sesquiterpenes from Ferula ferulaeoides (Steud.) Korovin. VI. Isolation and identification of three new dihydrofuro[2,3-b]chromones.

Three novel 2-prenyl-dihydrofurochromone-type sesquiterpenoid derivatives, 2,3-dihydro-7-hydroxy-2S*,3R*-dimethyl-2-[4,8-dimethyl-3(E),7-nonadienyl]-furo[2,3-b]chromone, 2,3-dihydro-7-hydroxy-2S*,3R*-dimethyl-2-[4-methyl-5-(4-methyl-2-furyl)-3(E),7-pentenyl]-furo[2,3-b]chromone, and 2,3-dihydro-7-hydroxy-2R*,3R*-dimethyl-2-[4-methyl-5-(4-methyl-2-furyl)-3(E),7-pentenyl]-furo[2,3-b]chromone, were isolated from the roots of Ferula ferulaeoides. The structures were established by comprehensive spectral analysis. The biosynthetic pathway leading to these 2-prenyl-dihydrofurochromone-type sesquiterpenoids is proposed based on their structures.

Asia, Central↗
PubMed2003

Four new 2-(2-phenylethyl)chromone derivatives from withered wood of Aquilaria sinensis.

Four new chromone derivatives, 5-hydroxy-6-methoxy-2-(2-phenylethyl)chromone (1), 6-hydroxy-2-(2-hydroxy-2-phenylethyl)chromone (2), 8-chloro-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydrochromone (3), 6,7-dihydroxy-2-(2-phenylethyl)-5,6,7,8-tetrahydrochromone (4) were isolated from the MeOH extract of withered wood of Aquilaria sinensis, together with seven known constituents of agarwood.

Chromatography, Thin Layer↗
PubMed1994

Antiviral activity of natural and semi-synthetic chromone alkaloids.

The activity against human immunodeficiency virus (HIV) and herpes simplex virus (HSV), of the non-polar fraction of a methanolic extract of the rootbark of Schumanniophyton magnificum was found to be present in a fraction containing the chromone secondary amine schumannificine 1. Other chromone alkaloids present in the plant were isolated and tested for inhibition of HIV and HSV infections in C8166 and Vero cells, respectively. Acyl and methyl derivatives were prepared and tested. Of all the compounds tested, schumannificine 1 displayed the greatest activity against HIV, whereas potent anti-HSV activity was observed for a number of its derivatives. The presence of a piperidine ring and unsubstituted hydroxy groups on the molecules seems to favour the anti-HIV activity. The anti-HIV activity is considered to be due to irreversible binding to gp120 rather than inhibition of reverse transcriptase or protease.

Alkaloids↗
PubMed2006

Synthesis, characterization, and DNA-binding properties of the Ln(III) complexes with 6-hydroxy chromone-3-carbaldehyde-(2'-hydroxy) benzoyl hydrazone.

A new ligand, 6-hydroxy chromone-3-carbaldehyde-(2'-hydroxy) benzoyl hydrazone (L), was prepared by condensation of 6-hydroxy-3-carbaldehyde chromone (CDC) with 2-hydroxy benzoyl hydrazine. Its four rare earth complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, mass spectra, 1H NMR, thermogravimetry/differential thermal analysis (TG-DTA), UV-vis spectra, fluorescence spectra, and IR spectra. The general formula of the complexes is [LnL2.(NO3)2].NO3 [Ln=La(1), Sm(2), Dy(3), Eu(4)]. Spectrometric titration, ethidium bromide displacement experiments, and viscosity measurements indicate that Eu(III) complex and ligand, especially the Eu(III) complex, strongly bind with calf-thymus DNA, presumably via an intercalation mechanism. The intrinsic binding constants of Eu(III) complex and ligand with DNA were 3.55 x 10(6) and 1.33 x 10(6)M(-1) through fluorescence titration data, respectively. In addition, the suppression ratio for O2-* and OH* of the ligand and its complexes was studied by spectrophotometric methods. The experimental results show that La (1), Sm (2), and Eu (4) complexes are better effective inhibitor for OH* than that of mannitol. It indicates that the complexes have the activity to suppress O2-* and OH* and exhibit more effective antioxidants than ligand alone.

Antineoplastic Agents↗
PubMed2005

Synthesis and biological evaluation of chromone carboxamides as calpain inhibitors.

Excessive calpain activations contribute to serious cellular damage and have been found in many pathological conditions. Novel chromone carboxamides derived from ketoamides were prepared and evaluated for mu-calpain inhibition. Among synthesized, compound 2i was the most potent calpain inhibitor with an IC(50) value of 0.24 +/- 0.11 microM comparable to the activity of peptide aldehyde calpain inhibitor MDL 28,170. Furthermore, compound 2i showed higher selectivity for mu-calpain over two related cysteine proteases cathepsin B and cathepsin L, suggesting the chromone ring as a good scaffold for selective mu-calpain inhibitors.

Calpain↗
PubMed2003

Insect antifeedant activity of flavones and chromones against Spodoptera litura.

The antifeedant polymethylated flavones 5-hydroxy-3,6,7,8,4'-heptamethoxyflavone, 5-hydroxy-3,6,7,8-tetramethoxyflavone, and 5,6-dihydroxy-3,7-dimethoxyflavone have been isolated from the cudweed, Gnaphalium affine D. Don (Compositae). These flavonoids and authentic analogues showed insect antifeedant activity against the common cutworm (Spodoptera litura F.). In a previous paper, it was suggested that there was no substituent on the B-ring of the flavonoid for the beneficial antifeedant activity against the common cutworm. These flavonoids having a phenyl group as the B-ring and the chromone as elimination of the B-ring from the flavonoids were used to test the hypothesis of the previously described B-ring effect. The known fact is that Sculletaria baicarensis (Rutaceae) produced the 2-phenyl flavone. Test compounds and their methylated derivatives were prepared from this material for the structure-activity relationship (SAR) study of insect antifeedant activity. In spite of the 2-phenyl flavonoids, some tested compounds did not show any insect antifeedant activity against the common cutworm, although these inactive flavonoids were deficient in the 6-substituent group on the A-ring of the flavonoid. This 6-position-substituted derivative almost showed strong insect antifeedant activity against common cutworm. Moreover, the tested flavonoids having a hydroxyl group as a substituent on any of the positions tended to increase the activity. These results suggested the importance of the 6-position substitution on the flavonoid; however, hydrophilic substituents decreased the activity. Baicalein (5,6,7-trihydroxyflavone) derivatives did not show any activity despite having the 6-substituent derivative. Although the activity of some chromones increased the activity of the flavone, the bulky B-ring was a disadvantage for the antifeedant activity. It was suggested that the charge on C(3) and C(5) of the flavonoid was important for the biological activity. Additionally, an adequate hydrogen bonding property, which is different from lipophilicity, was an advantage for the activity on the basis of a QSAR analysis.

Animals↗
PubMed1995

(Piperidinylalkoxy)chromones: novel antihistamines with additional antagonistic activity against leukotriene D4.

A series of novel chromone derivatives, in which the chromone moiety is connected to a (diphenylmethylene)-, (diphenylmethyl)-, or (diphenylmethoxy)piperidine via an alkyloxy spacer, were synthesized as antiallergic and antiasthmatic agents. In addition to their potent antihistaminic activity, the compounds also inhibit contraction in guinea pig ileum induced by leukotriene D4. When analyzed by radioligand binding assays in guinea pig lung membranes, one of the compounds, 7-[[3-[4-(diphenylmethylene)piperidin-1- yl]propyl]oxy]-2-(5-tetrazolyl)-4-oxo-4H-1-benzopyran, showed dissociation constants (KD) of 5.62 nM and 2.34 microM for H1- and LTD4-receptors, respectively. In vivo at the dose of 10 mg/kg, the compound inhibited the histamine- and LTD4-induced increase of vascular permeability in guinea pigs by 95 and 30%, respectively. The inhibition of LTD4-induced increase in vascular permeability by the compound was increased to 56% when a dose of 50 mg/kg was employed. Similar to terfenadine, the compound does not readily occupy the brain H1-receptors when given intraperitoneally to mice, implying no sedating side effects.

Animals↗
PubMed2001

A new class of nonsteroidal aromatase inhibitors: design and synthesis of chromone and xanthone derivatives and inhibition of the P450 enzymes aromatase and 17 alpha-hydroxylase/C17,20-lyase.

Aromatase (P450arom) is a target of pharmacological interest for the treatment of breast cancer. In this paper, we report the design, synthesis, and in vitro biological evaluation of a series of new (di)benzopyranone-based inhibitors of this enzyme. The design of the new compounds was guided by a CoMFA model previously developed for a series of nonsteroidal aromatase inhibitors. Both the chromone and the xanthone nuclei were taken as molecular skeletons, and the functions supposed to be critical for binding to the aromatase active site - a heterocyclic ring (imidazole or 1,3,4-triazole) linked to the aromatic moiety by a methylene unit and an H-bond accepting function (CN, NO(2), Br) located on the aromatic ring at a suitable distance from the heterocyclic nitrogen carrying the lone pair--were attached to them. The chromone, xanthone, and flavone derivatives were prepared by conventional synthetic methods from the appropriate methyl analogues. Aromatase inhibitory activities were determined by the method of Thompson and Siiteri, using human placental microsomes and [1 beta,2 beta-(3)H]testosterone as the labeled substrate. All the compounds were also tested on 17 alpha-hydroxylase/C17,20-lyase (P450 17), an enzyme of therapeutic interest for the treatment of prostatic diseases. The goal to find new potent inhibitors of aromatase was reached with the xanthone derivatives 22d,e (IC(50) values 43 and 40 nM, respectively), which exceeded the potency of the known reference drug fadrozole and also showed high selectivity with respect to P450 17. Moreover, compounds 22g-i based on the same xanthonic nucleus showed fairly high potency as P450 17 inhibitors (IC(50) values 220, 130, and 42 nM, respectively). Thus, they might be new leads for the development of drug candidates for androgen-dependent diseases.

Aromatase Inhibitors↗