In this study, we evaluated the abilities of a series of chalcones to inhibit the activity of the enzyme xanthine oxidase (XO) and to scavenge radicals. 20 mono- and polyhydroxylated chalcone derivatives were synthesized by Claisen-Schmidt condensation reactions and then tested for inhibitory potency against XO, a known generator of reactive oxygen species (ROS). In parallel, the ability of the synthesized chalcones to scavenge a stable radical was determined. Structure-activity relationship analysis in conjunction with molecular docking indicated that the most active XO inhibitors carried a minimum of three hydroxyl groups. Moreover, the most effective radical scavengers had two neighboring hydroxyl groups on at least one of the two phenyl rings. Since it has been proposed previously that XO inhibition and radical scavenging could be useful properties for reduction of ROS-levels in tissue, we determined the chalcones’ effects to rescue neurons subjected to ROS-induced stress created by the addition of β-amyloid peptide. Best protection was provided by chalcones that combined good inhibitory potency with high radical scavenging ability in a single molecule, an observation that points to a potential therapeutic value of this compound class.

Aromatase (CYP19) catalyzes the aromatization reaction of androgen substrates to estrogens, the last and rate-limiting step in estrogen biosynthesis. Inhibition of aromatase is a new and promising approach to treat hormone-dependent breast cancer. We present here the design and development of isoflavanone derivatives as potential aromatase inhibitors. Structural modifications were performed on the A and B rings of isoflavanones via microwave-assisted, gold-catalyzed annulation reactions of hydroxyaldehydes and alkynes. The in vitro aromatase inhibition of these compounds was determined by fluorescence-based assays utilizing recombinant human aromatase (baculovirus/insect cell-expressed). The compounds 3-(4-phenoxyphenyl)chroman-4-one (1h), 6-methoxy-3-phenylchroman-4-one (2a) and 3-(pyridin-3-yl)chroman-4-one (3b) exhibited potent inhibitory effects against aromatase with IC50 values of 2.4 μM, 0.26 μM and 5.8 μM, respectively. Docking simulations were employed to investigate crucial enzyme/inhibitor interactions such as hydrophobic interactions, hydrogen bonding and heme iron coordination. This report provides useful information on aromatase inhibition and serves as a starting point for the development of new flavonoid aromatase inhibitors.

CdTe quantum dots (QDs) were synthesized by a modified hydrothermal method with Na 2 TeO 3 as the Te source. Thioglycolic acid (TGA), thiolactic acid (TLA), 3mercaptopropionic acid (MPA), 3-mercaptobutyric acid (3MBA), 4-mercaptobutyric acid (MBA), and 5-mercaptovaleric acid (MVA) were used. Their effects on the growth and fluorescence of as-synthesized QDs were investigated: Detrimental precursor aggregation when using TGA-like molecules (TGA and L-cysteine) due to their special secondary coordination was observed and further confirmed by comparing with DL-homocysteine and N-acetyl-L-cysteine. The aggregation could be suppressed by using a bulky methyl group as a side chain to confine the carboxyl group, that is, TLA. Moreover, MPA was confirmed as a better stabilizer compared with linear TGA, MBA, and MVA probably because of its suitable balance between hydrophilicity and hydrophobicity. Accordingly, we designed and synthesized 3MBA that has the same main chain length as MPA but with a side methyl group as TLA. 3MBA-modified CdTe QDs exhibited an excellent optical property with a quantum yield of 71%, much higher than that of MPA and TGA. Preliminary results of CdSe QDs confirmed the versatility of 3MBA. Our results uncovered the possible origin of the advantages of mercapto acids with a methyl side chain and a suitable chain length.