HPLC isolation and spectroscopic characterization studies, along with the examination of DPPH radical scavenging capacity, were performed for identifying the major coumarin constituents of the bark extract of Aesculus hippocastanum L. collected from Turkey. The isolation process was carried out using a semi-preparative RP-HPLC with diode array detector. The major phenolic components of bark extract were identified by means of analytic RP-HPLC. Isolated compounds were characterized when necessary, along with comparison of available spectroscopic database, by UV-vis, H-1, C-1(3) NMR, FTIR, and HR-MS techniques. Radical scavenging capacity was determined by spectrophotometric DPPH assay. The isolated compounds A and B, in accordance with the RP-HPLC elution profile, were identified as 6-(beta-D-glucopyranosyloxy)-7-hydroxy-2H-1-benzopyran-2-one and 6,7-dihydroxycoumarin, whereas the third isolate compound C was characterized as 7,8-dihydroxy-6-methoxycoumarin. Compounds A and B exhibited important spectroscopic features with the emission maxima of 515nm and 445nm, respectively. The crude extract from A. hippocastanum bark revealed a remarkably high DPPH radical scavenging capacity with the EC50 value of 11.94 +/- 0.41 mu g/mL. The isolated components A, B, and C also exhibited scavenging capacities with EC50 values of 260.9 +/- 3.3, 4.83 +/- 0.04, and 494.8 +/- 16.4 (in mu g/mL), in the order of respective RP- HPLC profile.


Aromatic amino acid synthesis performance of bacillus acidocaldarius
Kocabaş, Pınar; Çalık, Pınar; Department of Chemical Engineering (2004)
In this study, the effects of bioprocess operation parameters on aromatic amino acid synthesis performance of Bacillus acidocaldarius were investigated. Firstly, in laboratory scale shake-bioreactors, a defined medium was designed in terms of its carbon and nitrogen sources, to achieve the highest cell concentration. Thereafter, the effects of bioprocess operation parameters, i.e., pH and temperature were investigated; and the optimum medium contained (kg m-3): fructose, 8; (NH4)2HPO4, 5; CaCl2, 0.2; KH2PO4...
Investigation for natural extract inhibitors of bovine lens aldose reductase responsible for the formation of diabetis dependent cataract
Onay, Melih; Çoruh, Nursen; Department of Biochemistry (2008)
In the polyol pathway, Aldose reductase (AR) is an important enzyme in reduction of aldehydes and aldosugars to their suitable alcohols. AR, using NADPH as a coenzyme, has a molecular weight of 37 000 dalton. AR in its activated form, known to increase the sorbitol accumulation in lens, is responsible for the cataract formation in diabetis diseases. Therefore, the inhibition of aldose reductase is important to prevent the incedence of cataract formation in diabetus mellitus. In the treatment of diabetis dep...
Interactions of cholesterol reducing agent simvastatin with phospholipid model membranes
Koçak, Mustafa; Severcan, Feride; Department of Biochemistry (2007)
Interactions of simvastatin with zwitterionic dipalmitoyl phosphotidylcholine (DPPC) multilamellar liposomes were investigated as a function of temperature and simvastatin concentration. And acyl chain length effect on the simvastatin-model membrane interactions was monitored with DPPC and dimyristoyl phosphotidylcholine (DMPC) lipids. All studies were carried out by two non-invasive techniques, namely Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The results s...
ELHALLAQ, YH; GOKMEN, IG; ARAS, NK; Gökmen, Ali (Royal Society of Chemistry (RSC), 1992-03-01)
A post-irradiation radiochemical separation technique was tested for the determination of selenium levels in diet samples, collected by using a duplicate portion technique, from both rural and urban population groups in Turkey. The technique involved sample irradiation, acid digestion, selective distillation, precipitation and filtration steps. During the separations it was possible to determine the yield of each sample using a stable selenium carrier. An average chemical yield of 71 +/- 3% was obtained ...
Characterization and modulation by drugs of sheep liver microsomal flavin monooxygenase activity
Demirdöǧen, Birsen Can; Adalı, Orhan (Wiley, 2005-07-01)
The flavin monooxygenases (FMO) catalyse the NADPH and oxygen-dependent oxidation of a wide range of nucleophilic nitrogen-, sulfur-, phosphorus-, and selenium heteroatom-containing chemicals, drugs, and agricultural agents. In the present study, sheep liver microsomal FMO activity was determined by measuring the S-oxidation rate of methimazole and the average specific activity obtained from different microsomal preparations was found to be 3.8 +/- 1.5 nmol methimazole oxidized min(-1) mg(-1) microsomal pro...
Citation Formats
N. Çoruh, “FLUORESCENT COUMARIN COMPONENTS OF THE BARK OF AESCULUS HIPPOCASTANUM,” JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES, pp. 1334–1350, 2014, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46436.