We synthesized a new chalcone (4,2'-dihydroxy-3methoxy-5-bromine chalcone; C) and structurally identified it via infrared spectrometry (IR), (1)H-NMR, mass spectrometry (MS) and element analysis (EA). C was confirmed to be highly potent in scavenging 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and OH free radicals in vitro. Tests of anti-free radical activity in response to oxidative stress in mice r...

Polyamino acids, such as polyleucine, behave as synthetic enzymes in the asymmetric epoxidation of chalcone and other electron-deficient alkenes (the Julià-Colonna reaction). The influences of reaction conditions, of the molecular structure of the catalysts and of the scaling-up of the process on the enantioselectivity of the reaction have been determined. The kinetics and mechanism have been i...

A molecular modeling study was carried out to develop a predictive model for combretastatin-like analogues populating the colchicine-binding site of beta-tubulin. A series of compounds built around a framework including two aromatic groups linked by various moieties such as alkenes (stilbenes), enones (chalcones), or ethers was selected for the study. The 5D-QSAR model was developed stepwise. F...

Anthocyanins are colorful plant pigments with promising applications as pharmaceuticals and colorants. In order to engineer efficient pigment biosynthesis in Escherichia coli, the activities of various dihydroflavonol 4-reductases (DFRs) were characterized for the three primary dihydroflavonol substrates. The biochemical assays demonstrated variable DFR activities for dihydroflavonol with one B...

The distribution patterns of flavonoids and cyclohexenyl chalcone derivatives in conventional propagated (CP) and in vitro-derived (CPA) field-grown plants of an important medicinal ginger, Boesenbergia rotunda, are described. A total of eight compounds were extracted from six organs (rootlet, rhizome, shoot base, maroon stem, stalk, and leaf) of the CP and CPA plants. Five major chromatographi...

Dietary flavonoids have attracted attention as chemopreventive agents. Chalcones are abundantly present in nature starting from ferns to higher plants. Chemically 1,3-diphenyl-2-propen-1-ones, these are often cytotoxic in vitro. The cellular defense system (including glutathione, glutathione-related enzymes, and antioxidant and redox enzymes) plays a crucial role in cell survival and growth in ...

A genomic clone encoding flavanone 3-hydroxylase (F3H) was isolated from Arabidopsis thaliana. The deduced amino acid sequence is 72 to 94% identical to all previously reported F3H proteins. Low-stringency DNA blot analysis indicated that F3H is encoded by a single gene in Arabidopsis. The F3H locus was mapped to the bottom of chromosome 3 and therefore does not correspond to any of the 13 flav...

A genomic clone encoding flavanone 3-hydroxylase (F3H) was isolated from Arabidopsis thaliana. The deduced amino acid sequence is 72 to 94% identical to all previously reported F3H proteins. Low-stringency DNA blot analysis indicated that F3H is encoded by a single gene in Arabidopsis. The F3H locus was mapped to the bottom of chromosome 3 and therefore does not correspond to any of the 13 flav...

Chenopodiaceae, Spinacia oleracea, Flavonoid Metabolism, Chalcone Synthase, Two Different Activities Chalcone synthase activity was found in enzyme preparations from spinach. In homogenates o f young leaves two different activities o f the enzyme could be separated by DEAE-ion exchange chromatography and chromatofocusing. Both activities formed naringenin with [2-14C] malonylCoA and 4-coumaroyl...

To evaluate the effect of increased expression of genes involved in flower pigmentation, additional dihydroflavonol-4-reductase (DFR) or chalcone synthase (CHS) genes were transferred to petunia. In most transformants, the increased expression had no measurable effect on floral pigmentation. Surprisingly, however, in up to 25% of the transformants, a reduced floral pigmentation, accompanied by ...