Photophysics of Curcumin excited state in toluene-polar solvent mixtures: Role of H-bonding properties of the polar solvent

Saini, R.K.; K, Das

doi:10.1016/j.jlumin.2013.08.060

Cited by 13 publications

(10 citation statements)

References 26 publications

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“…Curcumin (Scheme ) has three acidic protons, out of which the enolic proton is most acidic (p K a ∼8.4). , Results of several photophysical studies carried out on Curcumin suggest that intermolecular hydrogen bonding between the enolic proton of Curcumin and a hydrogen-bond-acceptor group in polar protic solvents is possible. − Because the molecule also has a strong affinity for membranes, − it is quite likely that there will be hydrogen-bonding interactions between the drug (Curcumin) and the polar head groups of the lipid when the drug is bound to the membrane. Results obtained from the pH experiment (Figure ) show that the observed 50% decrease in the E f 2ω of LDS when the pH is increased from 5.0 to 8.5 correlates with the ∼50% decrease in the concentration of the neutral form of the drug at pH 8.5.…”

Section: Discussionmentioning

confidence: 99%

Effect of Bilayer Partitioning of Curcumin on the Adsorption and Transport of a Cationic Dye Across POPG Liposomes Probed by Second-Harmonic Spectroscopy

et al. 2016

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The effect of Curcumin partitioning into the bilayer during the adsorption and transport of a cationic dye, LDS, across a negatively charged POPG bilayer was investigated by the interface-selective second-harmonic (SH) spectroscopic technique. The intensity of SH electric field (E) arising due to LDS adsorbed on the outer bilayer of the POPG liposome was observed to increase instantaneously (<1 s) following the addition of Curcumin. The fractional increase in the SH electric field (E) and the bilayer transport rates (k) of LDS were studied with respect to the pH of the solution and also with the Curcumin content in the lipid bilayer. Results obtained indicate that compared with the anionic form of the drug, its neutral form is more conducive of increasing the E of LDS. With increasing Curcumin content in the lipid bilayer, two distinct regimes could be observed in terms of E and k values of LDS. For Curcumin:Lipid (C/L) ratio ≤0.02, the E of LDS increases rapidly, while k remains unchanged; and for C/L ratio ≥0.02, the E values remains more or less constant, while there is a significant (∼40 times) increase followed by a modest increase in the k values of LDS. The observed results support an earlier two-state binding model of Curcumin with the POPG bilayer. In addition, it is further proposed that at low C/L ratio Curcumin binds to the surface of the bilayer replacing the counterions (Na) bound to the lipid head groups, which changes the bilayer surface charge density, thereby causing more LDS cations to adsorb on the bilayer surface. At high C/L ratio, Curcumin intercalates within the hydrophobic domain of the bilayer, altering its hydrophobicity and inducing enhanced transport of the LDS cation. Results presented in this work provide further insights into how Curcumin alters bilayer properties when it partitions from the aqueous to the bilayer phase.

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Section: Discussionmentioning

confidence: 99%

Effect of Bilayer Partitioning of Curcumin on the Adsorption and Transport of a Cationic Dye Across POPG Liposomes Probed by Second-Harmonic Spectroscopy

et al. 2016

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“…[34][35][36] Some latest studies on curcumin in various media like neat solvents, 37−39 micelles, 40 and vesicles, 41 elucidate the fact that one of the major photophysical processes in curcumin is the intramolecular hydrogen atom transfer between the hydroxyl group and the keto group of curcumin in the excited state followed by radiationless decay of excited-tautomer upon photoexcitation. The excited state dynamics of curcumin in various binary solvent mixtures has been reported recently by Das et al 42,43 They showed that various properties such as polarity, viscosity and hydrogen bonding played a vital role in the excited state dynamics of the pigment in toluene-alcohol mixture. The effects of acid and base have been extensively studied by Huppert and coworkers using time resolved techniques.…”

Section: Introductionmentioning

confidence: 89%

“…The excited state dynamics of curcumin in various binary solvent mixtures has been reported recently by Das and Saini. 42,43 They showed that various properties such as polarity, viscosity, and hydrogen bonding played a vital role in the excited state dynamics of the pigment in toluene−alcohol mixture. The effects of acid and base have been extensively studied by Huppert and coworkers using time-resolved techniques.…”

Section: Introductionmentioning

confidence: 99%

Effect of Encapsulation of Curcumin in Polymeric Nanoparticles: How Efficient to Control ESIPT Process?

et al. 2014

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This paper demonstrates the photophysics of curcumin inside polymeric nanoparticles (NPs), which are being recently used as targeted drug delivery vehicles. For this purpose, we have prepared three polymeric NPs by ultrasonication method from three well-defined water-insoluble random copolymers. These copolymers having various degrees of hydrophobicity were synthesized via reversible addition-fragmentation transfer (RAFT) method using styrene and three different functional monomers, namely, 2-hydroxyethyl acrylate, 4-formylphenyl acrylate, and 4-vinylbenzyl chloride. The photophysics of the curcumin molecules inside the polymeric NPs have been monitored by applying tools like steady state and time-resolved fluorescence spectroscopy. An increase in fluorescence intensity along with an increase in the lifetime values indicated a perturbation of the excited state intramolecular proton transfer (ESIPT) process of curcumin inside the polymeric NPs.

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“…Excited-state dynamics of curcumin has been extensively studied by ultrafast transient absorption and fluorescence spectroscopy [5,12,13,[16][17][18][19][20][21]. The lifetimes and quantum yields of curcumin strongly increase with the increase of the solvent polarity in general, which is seemingly related to the changes in the intramolecular hydrogen bonding of the enol form of curcumin in solution [17,22].…”

Section: Introductionmentioning

confidence: 99%

Intramolecular Charge Transfer of Curcumin and Solvation Dynamics of DMSO Probed by Time-Resolved Raman Spectroscopy

Jen

Lee

et al. 2022

IJMS

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Intramolecular charge transfer (ICT) of curcumin in dimethyl sulfoxide (DMSO) solution in the excited state was investigated by femtosecond electronic and vibrational spectroscopy. Excited-state Raman spectra of curcumin in the locally-excited and charge-transferred (CT) state of the S1 excited state were separated due to high temporal (<50 fs) and spectral (<10 cm−1) resolutions of femtosecond stimulated Raman spectroscopy. The ultrafast (0.6–0.8 ps) ICT and subsequent vibrational relaxation (6–9 ps) in the CT state were ubiquitously observed in the ground- and excited-state vibrational modes of the solute curcumin and the νCSC and νS=O modes of solvent DMSO. The ICT of curcumin in the excited state was preceded by the disruption of the solvation shells, including the breakage of hydrogen bonding between curcumin and DMSO molecules, which occurs at the ultrafast (20–50 fs) time scales.

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Photophysics of Curcumin excited state in toluene-polar solvent mixtures: Role of H-bonding properties of the polar solvent

Cited by 13 publications

References 26 publications

Effect of Bilayer Partitioning of Curcumin on the Adsorption and Transport of a Cationic Dye Across POPG Liposomes Probed by Second-Harmonic Spectroscopy

Effect of Bilayer Partitioning of Curcumin on the Adsorption and Transport of a Cationic Dye Across POPG Liposomes Probed by Second-Harmonic Spectroscopy

Effect of Encapsulation of Curcumin in Polymeric Nanoparticles: How Efficient to Control ESIPT Process?

Intramolecular Charge Transfer of Curcumin and Solvation Dynamics of DMSO Probed by Time-Resolved Raman Spectroscopy

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