Related Flavones Research Articles

Flavone inhibition of tumor growth via apoptosis in vitro and in vivo

Colorectal carcinoma is a human malignant tumor, which is very resistant to currently available methods of treatment. Therefore, developing an effective agent with anti-colorectal carcinoma activity is important. In the present study, 8 structurally related flavones including flavone, 3-OH flavone, 5-OH flavone, 7-OH flavone, quercetin, kaempferol, quercetin, and morin were used to study their effects on colorectal carcinoma cells (HT29, COLO205, COLO320-HSR). Results of MTT assay indicated that flavone shows the most potent cytoxic effect among them on these three cell types. The cytotoxicity induced by flavone is mediated by inducing the occurrence of apoptosis characterized by the appearance of DNA ladders, apoptotic bodies and hypodiploid cells. Activation of caspase 3 protein procession and enzyme activity with inducing cleavage of caspase 3 substrates PARP was identified in flavone-treated cells, and an inhibitory peptide Ac-DEVD-FMK for caspase 3, but not Ac-YVAD-FMK for caspase 1, attenuates the cytotoxic effect of flavone in COLO205 and HT29 cells. Elevation of p21 but no p53 protein was observed in flavone-treated cells. Increasing intracellular peroxide level was detected in flavone-treated cells by DCHF-DA assay, and antioxidants such as tiron, catalase, SOD, PDTC, but not DPI, suppress flavone-induced cytotoxic effect. In vivo anti-tumor study indicates that flavone exhibits ability to inhibit tumor formation elicited by s.c. injection of COLO205 cells in nude mice, and apoptotic cells and an increase in p21, but not p53, protein were observed in tumor tissues derived from flavone-treated group. Additionally, flavone induced apoptosis in primary colon carcinoma cells COLO205-X with appearance of DNA ladders, caspase 3 protein procession, PARP protein cleavage, and an increase in p21 (not p53) protein. These data provide evidence to suggest that flavone is an effective agent to induce apoptosis in colorectal carcinoma cells in vitro and in vivo; activation of caspase 3, ROS production, and increasing p21 protein are involved.

Influence of solvents on the antioxidant property of flavonoids.

In polyphenols redox systems, the solvent plays a fundamental role in the chemical behaviour of these compounds. Antioxidants can react in different ways with the prooxidant molecules. We have found differences in the antioxidant capacity of flavonoids such as naringin, neohesperidin, neoericitrin, hesperidin, narirutin didymin and the related flavones naringenin, hesperetin eriodictyol and isosakuatenin, when they are in the presence of radicals and solved in water or in an alcohol mixture.

Antiproliferative Constituents in Plants. 10. Flavones from the Leaves of Lantana montevidensis BRIQ. and Consideration of Structure-Activity Relationship.

The flavonoid fraction from the leaves of Lantana montevidensis Briq. (Verbenaceae) showed antiproliferative activity against human gastric adenocarcinoma (MK-1, GI50: 12 microg/ml), human uterus carcinoma (HeLa, 5 microg/ml), and murine melanoma (B16F10, 5 microg/ml) cells in vitro. Bioactivity-guided chemical investigation of the fraction has resulted in the isolation of apigenin (10) and ten 5,6,7-oxygenated flavones: cirsilineol (1), eupatorin (2), 5,4'-dihydroxy-6,7,3',5'-tetramethoxyflavone (3), 5,6-dihydroxy-7,3',4'-trimethoxyflavone (4), 5,6,4'-trihydroxy-7,3',5'-trimethoxyflavone (5), 5,6,3'-trihydroxy-7,4'-dimethoxyflavone (6), 5,3',4'-trihydroxy-6,7,5'-trimethoxyflavone (7), cirsiliol (8), hispidulin (9), and eupafolin (11). Antiproliferative activity of the isolated flavones, some other related flavones (luteolin, baicalein, 6-hydroxyluteolin, pectolinarigenin, jaceosidin, desmethoxycentaureidin, eupatilin, and chrysin) from other plant materials, and synthetic 6- and 7-methoxyflavones was evaluated, and the structure-activity relationships were examined.

Phytotoxic and antimicrobial activity of 5,7-dihydroxychromone from peanut shells

A flavonoid decomposition product that is present in peanut (Arachis hypogaea) shells, 5,7-dihydroxychromone (DHC), was found to inhibit the radial growth of cultures of the soil pathogenic fungiRhizoctonia solani andSclerotium rolfsii with I50 (the concentrations of DHC required to inhibit growth 50%) values of 18 and 26µM, respectively. Radicle elongation of velvetleaf, corn, peanut, and wheat was inhibited by DHC with I50 values of 30, 50, 65 and 200µM, respectively. DHC had no effect on the growth ofBradyrhizobium sp. at 10µM in medium containing low (1.0 g/liter) mannitol as the carbon source, although the related flavones luteolin and chrysin each promoted bacterial growth at 10µM 48 hr after inoculation. When tested in high (10.0 g/liter) mannitol medium, DHC initially inhibited growth ofBradyrhizobium sp., but 120 hr after inoculation the growth of all treatments were similar. These results suggest a role for DHC released from peanut shells in suppressing pathogenic fungal infection and competing plant growth but not forBradyrhizobium growth promotion.

Conformational analysis of 5,6,7‐trisubstituted flavones: 13C NMR and molecular mechanics study

Abstract13C NMR spectra of six flavones from Gomphrena martiana were analysed and compared with those of two related flavones isolated from Popowia cauliflora. This series of compounds has a similar substitution pattern on ring A, all compounds having oxygenated substituents on C‐5, C‐6 and C‐7. Consistent trends in relating conformation to substituent chemical shift effects (SCS) were found by analysing the 13C NMR data for these compounds. Chemical shifts for ring A carbons were calculated using the principle of additivity of substituents and by taking into account the conformation of the substituents. A reasonable agreement between the calculated shifts and the experimental values was found. A molecular mechanics study of these compounds was undertaken in order to obtain a set of consistent molecular structures to search for correlations between molecular structure and measured 13C chemical shifts. Good agreement was found between the predicted molecular mechanics conformations and the 13C NMR spectral data.

2-Phenoxychromones and a structurally related flavone from leaves of Rosa rugosa

Two phenoxychromones were identified in leaves of Rosa rugosa: 6-demethoxy-4′- O-methylcapillarisin and 6-demethoxycapillarisin. Apigenin was also found in the leaves. This is the first report of phenoxychromones outside the Compositae.

Two flavones from Psiadia arabica

Phytochemical examination of the aerial parts of Psiadia arabica yielded a small amount of the previously reported flavone psiadiarabin. In addition, two new related flavones were isolated and their structures determined by comparing their 1D and 2D NMR data with those of psiadiarabin. They were found to be 5,3′-dihydroxy-7,2′, 4′,5′-tetramethoxyflavone and 5-hydroxy-7,2′,3′,4′,5′-pentamethoxyflavone.

Inhibition of adenosine 3',5'-cyclic monophosphate phosphodiesterase by flavonoids. II.

Thirty-eight flavones obtained from Scutellaria baicalensis and ninety six related flavones were tested for inhibitory activity against adenosine 3', 5'-cyclic monophosphate phosphodiesterase from beef heart. The most active inhibitor is 8-methoxy-5, 7, 2'-trihydroxyflavone from S. baicalensis. Its IC50 value is 0.6(× 10-5 M/l). The structure-activity relationships were investigated. a) O-Methylated flavones generally show lower inhibitory activity than the corresponding hydroxyflavones among the flavones having under four substituents. b) O-Methylated flavones generally show higher inhibitory activity than the corresponding hydroxyflavones in the flavones having over five substituents. (c) C-Glycosides are almost all poor inhibitors. (d) O-Glycosides are generally less potent than the corresponding flavones.

8,2′-Dihydroxyflavone from Primula pulverulenta

A novel flavone, isolated from the farinose exudate of Primula pulverulenta, was identified as 8,2′-dihydroxyflavone. This is the first naturally occurring flavone, in which ring A is oxygenated only at C-8. The structure was deduced from spectral comparisons with the structurally related flavones: 5,2′-, 3,2′- and 2′,3′-dihydroxyflavone and confirmed by total synthesis. The spectral properties of other flavones oxygenation with a simple pattern are discussed in relation to 8,2′-dihydroxyflavone.

Unexpected specificity of iodine—potassium iodide spray reagent for closely related flavones

Unexpected specificity of iodine—potassium iodide spray reagent for closely related flavones

Formation of three new flavones by differentiating callus cultures of andrographis paniculata

Differentiating tissue cultures of Andrographis paniculata produce three new flavones, 5-hydroxy-7,8,2′-trimethoxy-, 5,2′-dihydroxy-7,8-dimethoxy- and 5-hydroxy-7,8-dimethoxy-flavones. Flavones are not synthesized by the de-differentiated callus. Closely related flavones have been isolated from intact plants of Andrographis species.

The 1,3-dihydroxy-5-oxonia-11-azabenzo[b]fluorene cation; a synthetic nitrogenous anthocyanidin

The chalcone formed from salicylaldehyde and indoxyl cyclises in warm trifluoroacetic acid to yield the 5-oxonia-11-azabenzo[b]fluorene cation (Ib). The constitution of this has been confirmed by oxidation with hydrogen peroxide to the related flavone, [1]benzopyrano[3,2-b]indol-11-one (XI), also accessible by heating 2′-nitroflavone with ethyl phosphite.

Advanced lower urinary obstruction in childhod.

Mucin 1 (MUC1) is a heterodimeric protein that is overexpressed in diverse human carcinomas. The oncogenic function of the MUC1 C-terminal subunit (MUC1-C) subunit is dependent on the formation of dimers through its cytoplasmic domain; however, it is not known whether MUC1-C can be targeted with small-molecule inhibitors. In the present work, an assay using the MUC1-C cytoplasmic domain (MUC1-CD) was established to screen small-molecule libraries for compounds that block its dimerization. Using this approach, the flavone apigenin was identified as an inhibitor of MUC1-CD dimerization in vitro and in cells. By contrast, the structurally related flavone baicalein was ineffective in blocking the formation of MUC1-CD dimers. In concert with these results, apigenin, and not baicalein, blocked the localization of MUC1-C to the nucleus. MUC1-C activates <i>MUC1</i> gene expression in an autoinductive loop, and apigenin, but not baicalein, treatment was associated with down-regulation of MUC1 mRNA levels and MUC1-C protein. The results also demonstrate that apigenin-induced suppression of MUC1-C expression is associated with apoptotic cell death and loss of clonogenic survival. These findings represent the first demonstration that the MUC1-C cytoplasmic domain is a target for the development of small-molecule inhibitors.

Rutin and related Flavones as New Drugs

Rutin and related Flavones as New Drugs

VITAMIN P IN VASCULAR PURPURA

Vitamin P was postulated by Szent-Gyorgyi 1 as a regulator of vascular permeability, isolated in crystalline form as a flavone glucoside from lemon juice and named citrin to indicate its chemistry. It was found to consist of mixed crystals of two related flavone dyes, the glucoside hesperidin C 50 H 60 O 27 and the glucoside of eriodictyol; the former constitutes the major part of citrin but the latter is responsible for the chemical reactivity and color production. The glucosides of citrin are but two forms of the same flavonone glucoside, the eriodictyol glucoside being formed from hesperidin by demethylation during ripening of citrus fruits, particularly lemon, orange and grapefruit. Citrin forms light yellow crystals sparingly soluble in water but very soluble in alkali, giving intense yellow solutions. The relative composition of the solid and liquid phases, respectively, is determined by the solubility of its two components; the crystals consist