Four kinds of solvent extracts from three Chinese barley varieties (Ken-3, KA4B, and Gan-3) were used to examine the effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley through free radical scavenging activity, reducing power and metal chelating activity, and individual and total phenolic contents. Results showed that extraction solvent mixtures had significant impacts on antioxidant activity estimation, as well as different extraction capacity and selectivity for free phenolic compounds in barley. The highest DPPH* and ABTS*+ scavenging activities and reducing power were found in 80% acetone extracts, whereas the strongest *OH scavenging activity, O2*- scavenging activity, and metal chelating activity were found in 80% ethanol, 80% methanol, and water extracts, respectively. Additionally, 80% acetone showed the highest extraction capacity for (+)-catechin and ferulic, caffeic, vanillic, and p-coumaric acids, 80% methanol for (-)-epicatechin and syringic acid, and water for protocatechuic and gallic acids. Furthermore, correlations analysis revealed that TPC, reducing power, DPPH* and ABTS*+ scavenging activities were well positively correlated with each other (p < 0.01). Thus, for routine screening of barley varieties with higher antioxidant activity, 80% acetone was recommended to extract free phenolic compounds from barley. DPPH* scavenging activity and ABTS*+ scavenging activity or reducing power could be used to assess barley antioxidant activity.
The various ethnic groups of Nepal consume a variety of traditional fermented and nonfermented foods. The major fermented traditional foods and beverages include
A highly enantioselective iridium-catalyzed hydrogenation of α-keto amides to form α-hydroxy amides has been achieved with excellent results (up to >99% conversion and up to >99% ee, TON up to 100 000). As an example, this protocol was applied to the synthesis of (S)-4-(2-amino-1-hydroxyethyl)benzene-1,2-diol, the enantiomer of norepinephrine, which is widely used as an injectable drug for the treatment of critically low blood pressure. Density functional theory (DFT) calculations were also carried out to reveal the reaction mechanism.
Herein, further SAR studies of lead compound NSC746457 (Shen, J.; Woodward, R.; Kedenburg, J. P.; Liu, X. W.; Chen, M.; Fang, L. Y.; Sun; D. X.; Wang. P. G. J. Med. Chem. 2008, 51, 7417-7427) were performed, including the replacement of the trans-styryl moiety with a 2-substituted benzo-hetero aromatic ring and the introduction of a substituent onto the central methylene carbon. A promising chiral lead, S-(E)-3-(1-(1-(benzo[d]oxazol-2-yl)-2-methylpropyl)-1H-1,2,3-triazol-4-yl)-N-hydroxyacrylamide (12, NK-HDAC-1), was discovered and showed about 1 order of magnitude more potency than SAHA in both enzymatic and cellular assays. For the in vitro safety tests, NK-HDAC-1 was far less toxic to nontransformed cells than tumor cells and showed no significant inhibition activity against CYP-3A4. The pharmaceutical properties (LogD, solubility, liver micrsomal stability (t1/2), plasma stability (t1/2), and apparent permeability) strongly suggested that NK-HDAC-1 might be superior to SAHA in bioavailability and in vivo half-life.
A series of novel and easily accessed ferrocene‐based amino‐phosphine‐sulfonamide (f‐Amphamide) ligands have been developed and applied in Ir‐catalyzed asymmetric hydrogenation of aryl ketones, affording the corresponding chiral secondary alcohols with excellent results (up to >99% conversion, >99% ee and TON up to 200 000). DFT calculations suggest an activating model involving an alkali cation Li+.
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