The aim of this work was to investigate the antioxidant property of honeybee products and their constituents using an ESR method. Antioxidative activity was evaluated as the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The DPPH radical scavenging activities, in descending order, were: ethanol extract of Chinese red propolis>ethanol extract of Brazilian green propolis>wat...

In this study, we examined the antitumor activities of isoprenoid derivatives conjugated with substrates of energy metabolism in human hepatoma-bearing athymic mice. Among these compounds, N-geranylpyruvic amide, N-geranyl-p-pyruvaminobenzoic amide, N,N'-digeranylmalic diamide and N,N'-digeranyl-O-acetylmalic diamide had strong antitumor effects. These geranylamine derivatives also inhibited in...

Silica-bonded n-propyldiethylenetriamine sulfamic acid (SBPDSA) was found as an efficient solid acid for the synthesis of coumarins. Coumarin derivatives were obtained via the Pechmann condensation reaction of phenols and β-keto-esters at 80 oC under solvent-free conditions. Also, biscoumarins were obtained via the condensation of aldehydes and 4-hydroxycoumarin in water at reflux conditions. T...

The (3,5-trans)-7-chloro-5-(2-chlorophenyl)-2-oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-acetic acid derivatives 1 have been previously identified as potent squalene synthase inhibitors. A series of (4,1-benzoxazepin-3-ylidene)acetic acid derivatives were synthesized and evaluated for their inhibition of rat and human squalene synthase, and the (E)-isomers were found to exhibit potent inhibitor...

Background: The aim of this study was to evaluate the radioprotective capacity of some novel aminoalkylated dithiocarbamic acid potassium salts against γ-irradiation in mice. Materials and Methods: Eight compounds containing 2-aminoethyl-, 3- aminopropyl-, 4-aminobutyl-, 5-aminopentyl-, 6- aminohexyl-, 7-aminoheptyl-, 8-aminooctyl and 9- aminononyl of dithiocarbamate derivatives were prepared. ...

3,4-ِDihydropyrano[c]chromene derivatives were synthesized using sulfonic acid functionalized silica (SiO2-Pr-SO3H) as a highly efficient heterogenous solid acid catalyst via one-pot three-component condensation of aromatic aldehydes with malononitrile and 4-hydroxycoumarin in excellent yields.

Silica boron sulfonic acid [SiO2–B(OSO3H)3] as an inexpensive, reusable, and Lewis and Brønsted acid catalyst was successfully synthesized, and used for the one-pot three-components synthesis of biologically active substituted Hantzsch 1,4-dihydropyridine derivatives  in the absence of solvent at 90ºC. Silica boron sulfonic acid is attractive and efficient, because it plays in two role as a Lew...

      Plants of Asteraceae are used in traditional medicine and phytotherapy. The two main caffeic acid derivatives, chicoric and caftaric acid which are found in many genus of Asteraceae including Echinacea exhibit important biological activities. The level of these acids in E. purpurea is affected by many factors such as growing situations, extraction methods, storage condit...

From the ethyl acetate soluble fraction of a methanol/water extract of the herb Eupatorium perfoliatum L. (Asteraceae) six caffeic acid derivatives have been isolated and identified by 1D- and 2D-NMR spectroscopic data. Besides the common quinic acid derivatives 5-caffeoylquinic acid (chlorogenic acid), 3-caffeoylquinic acid (neochlorogenic acid) and 3,5-dicaffeoylquinic acid, three up to now u...

Surface modification of nanocrystalline TiO(2) particles (45 A) with bidentate benzene derivatives (catechol, pyrogallol, and gallic acid) was found to alter optical properties of nanoparticles. The formation of the inner-sphere charge-transfer complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites. The binding structures were investigated by us...