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Studies on curcumin and curcuminoids. XXXIX. Photophysical properties of bisdemethoxycurcumin.

Nardo L, Andreoni A, Masson M, Haukvik T, Tønnesen HH - J Fluoresc (2010)

Bottom Line: The steady-state absorption and fluorescence, as well as the time-resolved fluorescence properties of bisdemethoxycurcumin dissolved in several solvents differing in polarity and H-bonding capability were measured.The bisdemethoxycurcumin decay mechanisms from the S(1) state were discussed and compared with those of curcumin.The differences in S(1) dynamics observed between bisdemethoxy-curcumin and curcumin could be ascribed to a difference in H-bond acceptor/donor properties of the phenolic OH and a difference in strength of the intramolecular H-bond in the keto-enol moiety within the two molecules.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Mathematics, University of Insubria and C.N.I.S.M.-C.N.R., Via Valleggio, 11- 22100 Como, Italy. luca.nardo@uninsubria.it

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a) Absorption and b) fluorescence emission spectra of bisDMC in cyclohexane (solid black line), acetone (solid grey line), DMSO (full dots) and methanol (empty circles). In panel b) inset the emission spectrum of bisDMC in cyclohexane obtained upon excitation at 420 nm (full line) is compared with that obtained upon excitation at 350 nm (triangles)
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Fig3: a) Absorption and b) fluorescence emission spectra of bisDMC in cyclohexane (solid black line), acetone (solid grey line), DMSO (full dots) and methanol (empty circles). In panel b) inset the emission spectrum of bisDMC in cyclohexane obtained upon excitation at 420 nm (full line) is compared with that obtained upon excitation at 350 nm (triangles)

Mentions: The absorption maxima, λAbs, of bisDMC in the different solvents are shown in Table 2. In all solvents except cyclohexane the absorption spectra were broad and essentially structureless and the absorption maximum was blue-shifted with respect to that of CURC [33]. Some representative spectra are reported in Fig. 3a. In cyclohexane, bisDMC was rather insoluble, and only a noisy spectrum could be recorded even for a saturated solution. The main absorption band was observed in the UV, with peaks at 348 nm and 362 nm, respectively. The spectrum also displayed a shoulder around 380 nm. A second absorption band above 400 nm was barely detectable. The situation was opposite for CURC in cyclohexane [33] where the main absorption band was indentified above 400 nm and the near UV band was minor. For both compounds a systematic red shift was observed when changing from cyclohexane to solvents with higher dielectric constants and from weaker to stronger H-bonding solvents of comparable polarity. However, there was no linear correlation between either ε, α or β and λAbs. Conversely, λAbs remained constant within one solvent category (see Table 2 for bisDMC and [33] for CURC), but was markedly different from one category to another.Table 2


Studies on curcumin and curcuminoids. XXXIX. Photophysical properties of bisdemethoxycurcumin.

Nardo L, Andreoni A, Masson M, Haukvik T, Tønnesen HH - J Fluoresc (2010)

a) Absorption and b) fluorescence emission spectra of bisDMC in cyclohexane (solid black line), acetone (solid grey line), DMSO (full dots) and methanol (empty circles). In panel b) inset the emission spectrum of bisDMC in cyclohexane obtained upon excitation at 420 nm (full line) is compared with that obtained upon excitation at 350 nm (triangles)
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3104010&req=5

Fig3: a) Absorption and b) fluorescence emission spectra of bisDMC in cyclohexane (solid black line), acetone (solid grey line), DMSO (full dots) and methanol (empty circles). In panel b) inset the emission spectrum of bisDMC in cyclohexane obtained upon excitation at 420 nm (full line) is compared with that obtained upon excitation at 350 nm (triangles)
Mentions: The absorption maxima, λAbs, of bisDMC in the different solvents are shown in Table 2. In all solvents except cyclohexane the absorption spectra were broad and essentially structureless and the absorption maximum was blue-shifted with respect to that of CURC [33]. Some representative spectra are reported in Fig. 3a. In cyclohexane, bisDMC was rather insoluble, and only a noisy spectrum could be recorded even for a saturated solution. The main absorption band was observed in the UV, with peaks at 348 nm and 362 nm, respectively. The spectrum also displayed a shoulder around 380 nm. A second absorption band above 400 nm was barely detectable. The situation was opposite for CURC in cyclohexane [33] where the main absorption band was indentified above 400 nm and the near UV band was minor. For both compounds a systematic red shift was observed when changing from cyclohexane to solvents with higher dielectric constants and from weaker to stronger H-bonding solvents of comparable polarity. However, there was no linear correlation between either ε, α or β and λAbs. Conversely, λAbs remained constant within one solvent category (see Table 2 for bisDMC and [33] for CURC), but was markedly different from one category to another.Table 2

Bottom Line: The steady-state absorption and fluorescence, as well as the time-resolved fluorescence properties of bisdemethoxycurcumin dissolved in several solvents differing in polarity and H-bonding capability were measured.The bisdemethoxycurcumin decay mechanisms from the S(1) state were discussed and compared with those of curcumin.The differences in S(1) dynamics observed between bisdemethoxy-curcumin and curcumin could be ascribed to a difference in H-bond acceptor/donor properties of the phenolic OH and a difference in strength of the intramolecular H-bond in the keto-enol moiety within the two molecules.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Mathematics, University of Insubria and C.N.I.S.M.-C.N.R., Via Valleggio, 11- 22100 Como, Italy. luca.nardo@uninsubria.it

Show MeSH
Related in: MedlinePlus