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An undescribed isoprenylated flavonol racemate, nigranol C, with an unprecedented 7/6/6 ring system, was isolated from the twigs of Morus nigra L. The structure was assigned through a comprehensive analysis of HRMS, IR, and NMR data. Chiral separation of nigranol C was successfully carried out to yield a pair of enantiomers, nigranol C-a and nigranol C-b, whose absolute configurations were determined by ECD calculation. A plausible biogenetic pathway for nigranol C was proposed. A previously isolated sanggenon-type flavonone racemate, nigragenon E, was also well resolved by chiral HPLC to offer another pair of enantiomers, nigragenon E-a and nigragenon E-b, whose stereo configurations were determined by ECD data. All of the isolated compounds showed prominent α-glucosidase inhibitory activities with IC values ranging from 9.79 to 30.21 μM, while only the sanggenon-type flavonones exhibited tyrosinase inhibitory effects comparable to that of the positive control, kojic acid, the IC value of which was 27.14 μM. In addition, it was found that the stereo configurations of these compounds seemed to play a negligible role in their inhibitory activities towards the two enzymes.
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The determination of the absolute configuration of natural products still faces many challenges, especially the active pharmaceutical ingredient which is trace, oily and novel structures. Currently, N...
A new racemic pyrazoline derivative was synthesized and resolved to its enantiomers using analytic and semipreparative high-pressure liquid chromatography. The absolute configuration of both fractions...
For the purpose of chiral separation and determination of benalaxyl enantiomers in tobacco and soil, we developed a rapid, green and sensitive method using ultra-performance convergence chromatography...
New chiral high-performance liquid chromatography (HPLC) method for the enantiomeric resolution of quinolones is developed and described. The column used was Chirobiotic T (150 × 4.6 mm, 5.0 μm)...
Chiral 2-bromopropionates are widely used as raw materials or intermediates for synthesis of chiral pesticides and medicines with high biological activities. Enantioseparation of 2-bromopropionates is...
This study will measure the effect of ingesting a flavonoid-rich supplement on various biomarkers in overweight/obese women during a 12-week period. The flavonoid-rich supplement contains ...
Flavonoids are one of the many classes of natural chemicals found in a variety of foods. People with the highest flavonoid blood levels have the lowest rates of coronary heart disease. Thi...
This study determines to evaluate the effectiveness of the daily consumption of flavonoid-rich cocoa in the treatment of fatigue in Parkinson's patients. The participants were divided equa...
The purpose of this study is to compare the effects on blood pressure of a daily intake of a flavonoid-rich cocoa drink with that of the same drink from which the flavonoids have been larg...
This study evaluates effect of anterior component separation and posterior component separation and transversus abdominis muscle release methods for treatment of midline ventral hernias.
Polymers of N-SUBSTITUTED GLYCINES containing chiral centers at the a-position of their side chains. These oligomers lack HYDROGEN BONDING donors, preventing formation of the usual intrachain hydrogen bonds but can form helices driven by the steric influence of chiral side chains.
The separation of individuals or groups resulting in the lack of or minimizing of social contact and/or communication. This separation may be accomplished by physical separation, by social barriers and by psychological mechanisms. In the latter, there may be interaction but no real communication.
The separation of particles from a suspension by passage through a filter with very fine pores. In ultrafiltration the separation is accomplished by convective transport; in DIALYSIS separation relies instead upon differential diffusion. Ultrafiltration occurs naturally and is a laboratory procedure. Artificial ultrafiltration of the blood is referred to as HEMOFILTRATION or HEMODIAFILTRATION (if combined with HEMODIALYSIS).
A plant genus of the family ASTERACEAE. Members contain pectolinarin (a flavonoid glycoside).
Anxiety experienced by an individual upon separation from a person or object of particular significance to him.