Spectroscopic Properties of Flavonoids in Various Aqueous-Organic Solvent Mixtures

Park, Hyoung‐Ryun; Yu, Dihua; Park, Jong Keun; Bark, Ki‐Min

doi:10.5012/bkcs.2013.34.1.211

Cited by 26 publications

(41 citation statements)

References 33 publications

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“…The average fluorescent reading from media-only wells was subtracted from the data output, accounting for background fluorescence. Apigenin did not interfere with the assay as it is weakly fluorescent in aqueous solutions [22]. …”

Section: Methodsmentioning

confidence: 99%

Apigenin inhibits pancreatic stellate cell activity in pancreatitis

Mrazek¹,

Porro²,

Bhatia³

et al. 2015

Journal of Surgical Research

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BACKGROUND Chronic pancreatitis (CP) is characterized by recurrent pancreatic injury, resulting in inflammation, necrosis, and fibrosis. There are currently no drugs limiting pancreatic fibrosis associated with CP, and there is a definite need to fill this void in patient care. MATERIALS AND METHODS Pancreatitis was induced in C57/BL6 mice using supraphysiologic doses of cerulein (CR), and apigenin treatment (once daily, 50 μg/mouse by oral gavage) was initiated one week into the recurrent acute pancreatitis (RAP) protocol. Pancreata were harvested after four weeks of RAP. Immunostaining with fibronectin antibody was used to quantify the extent of pancreatic fibrosis. To assess how apigenin may decrease organ fibrosis, we evaluated the effect of apigenin on the proliferation and apoptosis of human pancreatic stellate cells (PSCs) in vitro. Lastly, we assessed apigenin’s effect on gene expression in PSCs stimulated with parathyroid hormone related protein (PTHrP), a pro-fibrotic and pro-inflammatory mediator of pancreatitis, using RT-PCR. RESULTS After four weeks of RAP, apigenin significantly reduced the fibrotic response to injury while preserving acinar units. Apigenin inhibited viability and induced apoptosis of PSCs in a time and dose-dependent manner. Lastly, apigenin reduced PTHrP-stimulated increases in the PSC mRNA expression levels of extracellular matrix proteins collagen 1A1 and fibronectin, proliferating cell nuclear antigen, TGF-β, and IL-6. CONCLUSIONS These in vivo and in vitro studies provide novel insights regarding apigenin’s mechanism(s) of action in reducing the severity of RAP. Additional preclinical testing of apigenin analogs is warranted to develop a therapeutic agent for patients at risk for CP.

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Section: Methodsmentioning

confidence: 99%

Apigenin inhibits pancreatic stellate cell activity in pancreatitis

Mrazek¹,

Porro²,

Bhatia³

et al. 2015

Journal of Surgical Research

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“…In order to analyse adsorption isotherm of Acacia nilotica natural dye, saturated monolayer curve can be represented by Langmuir adsorption expression: (4) In the above equation, C f is the amount of dye adsorbed per gram of wool (mg/g) at equilibrium, S is the maximum amount of dye per unit weight of wool at equilibrium dye concentration C s , and K L the Langmuir constant related to the affinity of binding sites (ml/mg). The value of S represents a practical limiting adsorption capacity when the surface is fully covered with dye molecules.…”

Section: Equilibrium Adsorption Isothermsmentioning

confidence: 99%

“…Vast and diverse studies have been done regarding the fluorescence probing of biological macromolecules in order to study molecular interactions [1][2][3][4]. Several new applications of fluorescent dyes have emerged particularly exploiting their light emmision properties and mainly include non-destructive flaw detection [5], tunable dye lasers [6][7][8][9], liquid crystal displays [10,11], solar collectors [12], and electroluminicent displays [13].…”

Section: Introductionmentioning

confidence: 99%

Study on the application of Acacia nilotica natural dye to wool using fluorescence and FT-IR spectroscopy

2015

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The present study is aimed to exploit the intrinsic fluorescence emission properties of polyphenols of Acacia nilotica natural dye on natural protein fiber wool. Fluorescence measurements were done before and after dyeing experiments. Owing to these phytoconstituents dyed wool samples illustrate interesting fluorescence property with highest values recorded at 445 nm. Durability of fluorescence finish on exposure to ultraviolet radiations and upon washing has been studied and it was proven that dyed wool samples retain interesting fluorescence properties. Rate of fluorescence fading on exposure to UV radiations follows first order kinetics with decay constant of 9.84×10 -6 s -1 . Results showed adsorption isotherms are best explained by Langmuir type with high regression coefficient value (R 2 =0.998) and dyed wool fibers have an obvious fluorescent effect in the spectral range 400-470 nm. The effects of different metallic mordants on the fluorescence property of dyed wool have been assessed in order to increase fluorescence finish. Wool-mordant-dye interactions were studied by Fourier transform infrared (FT-IR) spectroscopy.

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“…However, when 370 nm radiation, which corresponded to the maximum absorption of Band I, was used as the excitation source, no fluorescence emission was observed in the same mixed solvents. 14,34 Similar fluorescence properties were also exhibited in AOT reverse micelles. As shown in Figure 3, steady-state fluorescence emission spectra were observed around 345 nm when 270 nm radiation was used as the excitation light, but no fluorescence spectra were observed when the 370 nm longwavelength light was used to excite the molecule.…”

Section: Resultsmentioning

confidence: 58%

“…Also, since the QCT has both an electron donor and acceptor, it will become good donor-acceptor-conjugated molecule. 14,18,34 At the excited state, the initial molecules (N) will become of the charge transferred zwitterionic form (T) induced by the excited state intramolecular charge transfer (ESICT). The T form will be stabilized further owing to the large delocalization of the π electrons throughout the whole molecule.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic Properties of Quercetin in AOT Reverse Micelles

Park¹,

Im²,

Seo³

et al. 2014

Bulletin of the Korean Chemical Society

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The spectroscopic properties of quercetin (QCT) were studied in the AOT reverse micelle by fluorescence spectroscopy. Because the molecular structure of QCT is completely planar, excited state intramolecular proton transfer (ESIPT) occurs between the -OH at C(5) and carbonyl oxygen via intramolecular hydrogen bonding. This ESIPT happens at the S1 state but not at the S2 state. Because QCT is a good donor-acceptor-conjugated molecule at the excited state, this molecule can emit strong fluorescence but shows no S1 → So emission due to this ESIPT. Since the S2 → S1 internal conversion was very slow due to the small Franck-Condon factors, S2 → So fluorescence emission was observed. All of the experimental results indicated that the QCT resided at the bound water interface and that the position of solute did not change significantly in the micelle at various water concentrations.

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Spectroscopic Properties of Flavonoids in Various Aqueous-Organic Solvent Mixtures

Cited by 26 publications

References 33 publications

Apigenin inhibits pancreatic stellate cell activity in pancreatitis

Apigenin inhibits pancreatic stellate cell activity in pancreatitis

Study on the application of Acacia nilotica natural dye to wool using fluorescence and FT-IR spectroscopy

Spectroscopic Properties of Quercetin in AOT Reverse Micelles

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