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Coumarin derivative 1, 5,7-dihydroxy-6-(3-methyl-1-butyryl)-4-phenyl-chromen- 2-one, has been reported to possess radical scavenging activity and DNA protection. We have synthesized a series of coumarins with structural modifications at positions C4, C5, C6 and C7 and evaluated them for their anti-UVC properties. Coumarin 7, 6-benzoyl-5,6-dihydroxy-4-phenyl-chromen-2-one, was found to have the most potent activity in protecting porcine γ-crystallin against UVC insults. Results of fluorescence assays indicated that compound 7 was capable of decreasing the loss of intensity while lens crystallins and DNA PUC19 were irradiated with UVC. Presence of compound 7 decreased hydroxyl radical levels determined by probe 1b and the free iron concentrations determined by Ferrozine reagent. The chelation assay showed that compound 7 was chelated to metal via 6-CO and 5-OH on the benzopyrone ring. The observed protective effects of compound 7 towards crystallins from insults of UVC and free radicals may be due to its iron-chelating activity and its peak absorption at 254 nm.  相似文献   
2.
This study synthesized a europium (Eu(3+)) complex Eu(DBM)(3)Cl-MIP (DBM = dibenzoyl methane; Cl-MIP = 2-(2-chlorophenyl)-1-methyl-1H-imidazo[4,5-f][1,10]phenanthroline) dispersed in a benzyl methacrylate (BMA) monomer and treated with ultraviolet (UV) light for polymerization. Spectral results showed that the europium complex containing an antenna, Cl-MIP, which had higher triplet energy into the Eu(3+) energy level, was an energetically enhanced europium emission. Typical stacking behaviors of π-π interactions between the ligands and the Eu(3+)-ion were analyzed using single crystal X-ray diffraction. Regarding the luminescence performance of this europium composite, the ligand/defect emission was suppressed by dispersion in a poly-BMA (PBMA) matrix. The underlying mechanism of the effective enhancement of the pure Eu(3+) emission was attributed to the combined effects of structural modifications, defect emissions, and carrier charge transfer. Fluorescence spectra were compared to the composite of optimized Eu3+ emission where they were subsequently chelated to four metal ions via carboxylate groups on the BMA unit. The optical enhanced europium composite clearly demonstrated highly efficient optical responses and is, therefore a promising application as an optical detection material.  相似文献   
3.
Thirteen polyphenolics were isolated from fresh pods of Caesalpinia pulcherrima using various methods of column chromatography. The structures of these polyphenolics were elucidated as gallic acid (1), methyl gallate (2), 6-O-galloyl-d-glucoside (3), methyl 6-O-galloyl-β-d-glucoside (4), methyl 3,6-di-O-galloyl-α-d-glucopyranoside (5), gentisic acid 5-O-α-d-(6'-O-galloyl)glucopyranoside (6), guaiacylglycerol 4-O-β-d-(6'-O-galloyl)glucopyranoside (7), 3-methoxy-4-hydroxyphenol 1-O-β-d-(6'-O-galloyl) glucopyranoside (8), (+)-gallocatechin (9), (+)-catechin (10), (+)-gallocatechin 3-O-gallate (11), myricetin 3-rhamnoside (12), and ampelopsin (13). All isolated compounds were tested for their antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and peroxynitrite radicals scavenging assays. Among those compounds, 11, 12, and 2 exhibited the best DPPH-, hydroxyl-, and peroxynitrite radical-scavenging activities, respectively. Compound 7 is a new compound, and possesses better scavenging activities towards DPPH but has equivalent hydroxyl radical scavenging activity when compared to BHT. The paper is the first report on free radical scavenging properties of components of the fresh pods of Caesalpinia pulcherrima. The results obtained from the current study indicate that the free radical scavenging property of fresh pods of Caesalpinia pulcherrima may be one of the mechanisms by which this herbal medicine is effective in several free radical mediated diseases.  相似文献   
4.
Sixty elementary school age children qualified as symptomatic of attention deficit/hyperactivity disorder (ADHD) were randomly assigned to 1 of 2 treatment conditions: child-centered play therapy (CCPT) or reading mentoring (RM). All children participated in 16 individual 30-min sessions in the schools. Results indicated that children who participated in 16 sessions of CCPT and RM demonstrated statistically significant improvement on the ADHD and student characteristics domains, as well as the Anxiety/Withdrawal and Learning Disability subscales of the Index of Teaching Stress and the ADHD Index of the Conners Teacher Rating Scale--Revised: Short Form. Children who participated in CCPT demonstrated statistically significant improvement over RM children on the student characteristics domain and on the Emotional Lability and Anxiety/Withdrawal subscales of the Index of Teaching Stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
In this study we investigated the prediction of child centered play therapy (CCPT)/nondirective play therapy on emotional and behavioral problems using archival data from 82 child clients at a university-based counseling clinic. Statistically significant predictions were found on the Internalizing and Externalizing Problems scales on the Child Behavior Checklist. Termination and family relationship concerns variables were found to be strong contributors to predicting greater improvement. Results are discussed concerning implications for clinical practice and further research. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
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