1-1-diphenyl-2-picrylhydrazyl and chrysin

49 samples of propolis from different regions in China were collected and analyzed for their chemical compositions, contents of total flavonoids (TFC), total phenolic acid (TPC) and antioxidant activity. High-performance liquid chromatography (HPLC) analysis identified 15 common components, including key marker compounds pinocembrin, 3-

Topics: Antioxidants; Biphenyl Compounds; China; Chromatography, High Pressure Liquid; Flavonoids; Free Radical Scavengers; Humans; Phenols; Picrates; Propolis

Chrysin-based sulfonylpiperazines 7a-k were synthesized and investigated for their in vitro free radical scavenging potential as well as cytotoxic efficacies against selected cancer cell lines. Cytotoxicity of the new compounds toward noncancer cells was confirmed using the SRB assay against Madin-Darby Canine Kidney cells. Reaction of piperazine with different substituted benzenesulfonyl chlorides in triethylamine furnished sulfonylpiperazines (3a-k), which were then allowed to react with 7-(4-bromobutoxy)-5-hydroxy-2-phenyl-4H-chromen-4-one (6) prepared reacting chrysin with 1,4-dibromobutane to give the final derivatives 7a-k. The results concluded that chrysin-sulfonylpiperazines exerted better antioxidant and anticancer efficacies than previously studied chrysin-piperazine precursors. For example, compounds 7h, 7j, and 7k with 4-OCF

Topics: A549 Cells; Animals; Antineoplastic Agents; Antioxidants; Benzothiazoles; Biphenyl Compounds; Cell Survival; Dogs; Flavonoids; Free Radicals; HeLa Cells; HT29 Cells; Humans; Inhibitory Concentration 50; Madin Darby Canine Kidney Cells; Molecular Structure; Picrates; Sulfonic Acids

Two new diarylheptanoids, 1-(3',5'-dihydroxy-4'-methoxyphenyl)-7-phenyl-3-heptanone (1) and 1-(2',4'-dihydroxy-3'-methoxyphenyl)-7-(4″-methoxyphenyl)-3-heptanone (2), along with known diarylheptanoid yakuchinone A (3), and five flavanoids, tectochrysin (4), chrysin (5), izalpinin (6), kaempferol 7, 4'-dimethyl ether (7), and kaempferide (8) were isolated from the fruits of Alpinia oxyphylla Miq. Their structures were determined by means of spectroscopic methods. Antioxidant activities of all the isolated compounds were evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 1-3 and 6-8 exhibited potent antioxidant activities in the DPPH assay.

Topics: Alpinia; Antioxidants; Biphenyl Compounds; Diarylheptanoids; Drugs, Chinese Herbal; Flavonoids; Fruit; Guaiacol; Kaempferols; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Picrates

The present study aims to establish the relationship between the reported radical-scavenging activities of flavonoids and some enthalpy changes that may occur during flavonoids' reactions with free radicals.. Eight flavonoids were chosen for the study on the basis of their structural merits and reported 1,1-diphenyl-2-picryl-hydrazyl scavenging activities. Enthalpy changes accompanying interconversions between selected conformations (including spin multiplicities) and homolytic dissociations were estimated.. A novel relationship exists between the total enthalpy of reaction for the abstraction of two hydrogen atoms from flavonoids, their reported radical-scavenging activities and the enthalpy of the homolytic dissociation of hydrogen molecule (104.206 kcal mol(-1)). Only those flavonoids which could give up two hydrogen atoms with total enthalpy changes well below 104.206 kcal mol(-1) were active radical scavengers.. By appealing to equilibrium dynamics, we demonstrated that, for flavonoids to be able to donate hydrogen atoms, the change in enthalpy accompanying the abstraction of two hydrogen atoms needs to be less than 104.206 kcal mol(-1). This condition does not seem to be restricted to flavonoids only but rather generally applicable to chian-breaking antioxidants.. Thermodynamical relationships may be the most important factors governing the radical-scavenging reactions of flavonoids and possibly other compounds as well. Nevertheless, a more complete characterization of antioxidants would necessitate kinetic analysis.

Topics: Biphenyl Compounds; Computational Biology; Flavones; Flavonoids; Free Radical Scavengers; Hydrogen; Hydrogen Bonding; Molecular Conformation; Picrates; Thermodynamics

Seven flavonoids have been isolated from the aerial parts of Halostachys caspica C. A. Mey. (Chenopodiaceae) for the first time. By means of physicochemical and spectrometric analysis, they were identified as luteolin (1), chrysin (2), chrysin 7-O-β-D-glucopyranoside (3), quercetin (4), quercetin 3-O-β-D-glucopyranoside (5), isorhamentin-3-O-β-D-glucopyranoside (6), and isorhamentin-3-O-β-D-rutinoside (7). All flavonoids were evaluated to show a broad antimicrobial spectrum of activity on microorganisms including seven bacterial and one fungal species as well as pronounced antioxidant activity. Among them, the aglycones with relatively low polarity had stronger bioactivity than their glycosides. The results suggested that the isolated flavonoids could be used for future development of antimicrobial and antioxidant agents, and also provided additional data for supporting the use of H. caspica as forage.

Topics: Anti-Infective Agents; Antioxidants; Bacteria; Biological Assay; Biphenyl Compounds; Chenopodiaceae; Flavonoids; Flavonols; Fungi; Glucosides; Luteolin; Magnetic Resonance Spectroscopy; Picrates; Quercetin

Pharmacologically motivated natural product investigations have yielded a large variety of structurally unique lead compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. In the present investigation, a series of benzyl substituted-flavone derivatives have been synthesized from the lead compounds and were screened against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibitory properties. The resulting activity profiles of these flavone derivatives were compared for degree of similarity to the profile of 1-3. Most of the synthesized derivatives displayed potent activities when compared to the parent compounds. Maximum potencies for DPPH free radical scavenging activity were observed only in compounds containing the 4-hydroxyl substitution and 3-methoxyl group on the phenyl ring. While the 2- and 4-hydroxyl group substitutions on the phenyl ring seem to be crucial for the intestinal α-glucosidase inhibitory activity.

Topics: Benzene Derivatives; Bignoniaceae; Biphenyl Compounds; Flavanones; Flavonoids; Free Radical Scavengers; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; India; Molecular Structure; Picrates; Plant Roots; Plants, Medicinal