Two possible isomers of some 1,3-diaryl-H-benzo[f]chromene have been studied using density functional theory. Structures of E1 and E2 isomers were optimized at the B3LYP and MP2 levels with different basis sets. The total electronic energies show that E2 isomer is about 3-5 kcal/mol more stable than E1 isomer and this energy difference is attributed to the planarity of heterocyclic ring and mor...

Incorporation of unnatural amino acids and peptidomimetic residues into therapeutic peptides is highly efficacious and commonly employed, but generally requires laborious trial-and-error approaches. Previously, we demonstrated that C20 peptide has the potential to be a potential antiviral agent. Herein we report our attempt to improve the biological properties of this peptide by introducing pep...

5(6)-Carboxy-rhodamine 110 isomers were rapidly synthesized by condensation of 3-aminophenol and trimellitic anhydride using microwave irradiation as heating method. After esterification of the two isomers, separation and hydrolyzation provided target products,5-carboxy-rhodamine 110 and 6-carboxy-rhodamine 110, in high yields. The results shows microwave irradiation can effectively reduce ...

Dietary lycopene consists mostly of the (all-E) isomer. Upon absorption, (all-E) lycopene undergoes isomerisation into various (Z)-isomers. Because these isomers offer potentially better health benefits than the (all-E) isomer, the aim of the present study was to investigate if the profile of lycopene isomers in intestinal lipoproteins is affected by the profile of lycopene isomers in the meal ...

many properties of chemicals depend on their streochemistry. among these, the effects of streoisomerism on percutaneous absorption of drugs, which is subject of the present investigation, is not well studied yet. in this study, tretinoin (tt) and isotretinoin (itt) (geometric isomers) were chosen and their permeations (alone or in the presence of each other) through enhancer-treated excised rat...

Although the biotransformation of ginsenosides in the gastrointestinal tract has been extensively studied, much less is known about hepatic cytochrome P450 (P450)-catalyzed metabolism. The major aims of this study were to clarify the metabolic pathway and P450 isoforms involved and to explore the structure-metabolism relationship of protopanaxatriol (PPT)-type ginsenosides in hepatic microsomes...

The ability of rat liver microsomes to catalyze UDP-glucuronic acid-dependent glucuronidation of monohydroxy-bile acids was examined. The following bile acids were used as substrates, each as the 3 alpha and 3 beta epimer: 3-hydroxy-5 beta-cholanoic acid (C24), 3-hydroxy-5 beta-norcholanoic acid (C23), 3-hydroxy-5 beta-bisnorcholanoic acid (C22), 3-hydroxy-5 beta-pregnan-21-oic acid (C21), and ...