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At least 343 records · Page 19Linked to original sources
PubMed1977

Stabilization of flow properties of blood with phenylbenzo-gama-pyrone derivatives (flavonoids).

An investigation conducted on erythrocytes suspension in plasma revealed an instability caused by apparent sensitivity of erythrocytes to aggregation due to slight changes in normal plasma constituents. There is evidence that low level intravascular aggregation and so-called normal erythrocyte sedimentation rate (ESR) of apparently healthy people may be caused by undue sensitivity of erythrocytes to aggregation by plasma constituents as they vary within accepted normal ranges. Certain flavones, particularly methoxylated compounds, which may occur in the diet, increase resistance of erythrocytes to aggregation by shifts in plasma constituents. The stabilizing and apparent regulatory action of flavonoids on parameters important in the rheology of blood supports the concept that these compounds are necessary in the diet.

ABO Blood-Group System↗
PubMed1976

Regulatory action of phenylbenzo-gamma-pyrone (PBP) derivatives on blood constituents affecting rheology in patients with coronary heart disease (CHD).

In patients with CHD the hematological and serum chemical profiles showed significantly elevated (P less than 0.05) serum cholesterols, highly significantly increased hematocrits (P less than 0.025 to P less than 0.001) and the erythrocyte sedimentation rates (ESR) (red cell aggregation) along with several blood constituents causal of erythrocyte aggregation were significantly elevated (P less than 0.05 to P less than 0.025). Thus, major defects were elevated serum cholesterol, increased blood viscosity and reduced tissue perfusion which present evidence implicates as interactive factors in the pathogenesis of CHD. Methoxylated PBP derivatives exhibited a highly significant antiadhesive action (P less than 0.001) on erythrocytes and certain PBP hydroxylated glycosides showed a significant accelerating (P less than 0.05) action on erythrocyte aggregation which causes sequestration and reduced erythrocyte concentration. Thus, the PBP derivatives exert an apparent regulatory action on erythrocyte aggregation and concentration, two major factors affecting blood viscosity and flow. The PBP compounds occur in plants and are found in certain foods which suggests dietary control of the blood high viscosity syndrome.

Aged↗
PubMed2006

Antifungal activity of 4-methyl-6-alkyl-2H-pyran-2-ones.

A number of 4-methyl-6-alkyl-alpha-pyrones were synthesized and characterized on the basis of 1H NMR and mass spectroscopy. These compounds were tested in vitro against pathogenic fungi, namely, Sclerotium rolfsii Saccardo, Rhizoctonia bataticola (Taub.) Butler, Pythium aphanidermatum (Edson) Fitz., Macrophomina phaseolina (Tassi), Pythium debaryanum (Hesse), and Rhizoctonia solani Nees. Lower homologues were less effective, whereas compounds such as 4-methyl-6-butyl-alpha-pyrone, 4-methyl-6-pentyl-alpha-pyrone, 4-methyl-6-hexyl-alpha-pyrone, and 4-methyl-6-heptyl-alpha-pyrone were found effective against all of the test fungi. They inhibited mycelial growth by approximately 50% (ED50) at 15-50 microg/mL. 4-Methyl-6-hexyl-alpha-pyrone, which was found most effective, was tested against S. rolfsii in a greenhouse at 1, 5, and 10% concentrations. The 10% aqueous emulsion of 4-methyl-6-hexyl-alpha-pyrone suppressed disease development in tomato by 90-93% as compared with the untreated infested soil in the greenhouse after 35 days of treatment.

Alkylation↗
PubMed2006

Bioactive properties of iron-containing carbon monoxide-releasing molecules.

Carbon monoxide-releasing molecules (CO-RMs) are compounds capable of delivering controlled amounts of CO within a cellular environment. Ruthenium-based carbonyls [tricarbonyldichloro ruthenium(II) dimer and tricarbonylchloro-(glycinato)ruthenium(II)] and boronacorbonates (sodium boranocarbonate) have been shown to promote vasodilatory, cardioprotective, and anti-inflammatory activities in a variety of experimental models. Here, we extend our previous studies by showing that eta-4-(4-bromo-6-methyl-2-pyrone)tricarbonyl iron (0) (CORM-F3), an irontricarbonyl complex that contains a 2-pyrone motif, liberates CO in vitro and exerts pharmacological actions that are typical of CO gas. Specifically, CORM-F3 caused vasorelaxation in isolated aortic rings and inhibited the inflammatory response (e.g., nitrite production) of RAW264.7 macrophages stimulated with endotoxin in a dose-dependent fashion. By analyzing the rate of CO release, we found that when the bromide at the 4-position of the 2-pyrone CORM-F3 is substituted with a chloride group [eta-4-(4-chloro-6-methyl-2-pyrone)tricarbonyl iron (0) (CORM-F8)], the rate of CO release is significantly decreased (4.5-fold), and a further decrease is observed when the 4- and 6-positions are substituted with a methyl group [eta-4-(4-methyl-6-methyl-2-pyrone)tricarbonyl iron (0) (CORM-F11)] or a hydrogen [eta-4-(4-chloro-2-pyrone)tricarbonyl iron (0) (CORM-F7)], respectively. Interestingly, the compounds containing halogens at the 4-position and the methyl at the 6-position of the 2-pyrone ring (CORM-F3 and CORM-F8) were found to be less cytotoxic compared with other CO-RMs when tested in RAW246.7 macrophages. Thus, iron-based carbonyls mediate pharmacological responses that are achieved through liberation of CO and the nature of the substituents in the organic ligand have a profound effect on both the rate of CO release and cytotoxicity.

Animals↗
PubMed1998

Kavain, dihydrokavain, and dihydromethysticin non-competitively inhibit the specific binding of [3H]-batrachotoxinin-A 20-alpha-benzoate to receptor site 2 of voltage-gated Na+ channels.

The mode of action of the kava pyrones, kavain, dihydrokavain and dihydromethysticin on the specific binding of [3H]-batrachotoxinin-A 20-alpha-benzoate to epitope 2 of voltage-dependent Na+ channels was investigated by performing saturation experiments in the presence and absence of these kava pyrones. The tested compounds significantly decreased the apparent total number of binding sites (Bmax) for [3H]-batrachotoxinin-A 20-alpha-benzoate (control: 0.5 pmol/mg protein, kava pyrones: 0.2-0.27 pmol/mg protein) with little change in the equilibrium constants (KD) for [3H]-batrachotoxin-A 20-alpha-benzoate (control: 28.2 nM, kava pyrones: 24-31 nM). The results indicate for the kava pyrones a non-competitive inhibition of the specific [3H]-batrachotoxinin-A 20-alpha-benzoate binding to receptor site 2 of voltage-gated Na+ channels.

Animals↗
PubMed1987

Photodimerization of 4,6,4'-trimethylangelicin and 6,5-dimethylangelicin.

4,6,4'-Trimethylangelicin and 6,5'-dimethylangelicin form C4-cyclodimers when irradiated in water-ethanol solution. The former compound yields a pyrone-pyrone dimer similar to that formed by psoralens. 6,5'-Dimethylangelicin forms both pyrone-pyrone and pyrone-furan dimers; this unusual dimer has the cis-syn configuration.

Furocoumarins↗
PubMed2001

Novel ring cleavage products in the biotransformation of biphenyl by the yeast Trichosporon mucoides.

The yeast Trichosporon mucoides, grown on either glucose or phenol, was able to transform biphenyl into a variety of mono-, di-, and trihydroxylated derivatives hydroxylated on one or both aromatic rings. While some of these products accumulated in the supernatant as dead end products, the ortho-substituted dihydroxylated biphenyls were substrates for further oxidation and ring fission. These ring fission products were identified by high-performance liquid chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance analyses as phenyl derivatives of hydroxymuconic acids and the corresponding pyrones. Seven novel products out of eight resulted from the oxidation and ring fission of 3,4-dihydroxybiphenyl. Using this compound as a substrate, 2-hydroxy-4-phenylmuconic acid, (5-oxo-3-phenyl-2,5-dihydrofuran-2-yl)acetic acid, and 3-phenyl-2-pyrone-6-carboxylic acid were identified. Ring cleavage of 3,4,4'-trihydroxybiphenyl resulted in the formation of [5-oxo-3-(4'-hydroxyphenyl)-2,5-dihydrofuran-2-yl]acetic acid, 4-(4'-hydroxyphenyl)-2-pyrone-6-carboxylic acid, and 3-(4'-hydroxyphenyl)-2-pyrone-6-carboxylic acid. 2,3,4-trihydroxybiphenyl was oxidized to 2-hydroxy-5-phenylmuconic acid, and 4-phenyl-2-pyrone-6-carboxylic acid was the transformation product of 3,4,5-trihydroxybiphenyl. All these ring fission products were considerably less toxic than the hydroxylated derivatives.

Biodegradation, Environmental↗