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This study suggests sulfuretin as an ant-skin aging agent. Sulfuretin significantly reduces solar UV (sUV)-increased matrix metalloproteinase-1 (MMP-1) expression and c-Jun phosphorylation in human dermal fibroblasts as well as skin tissue. An examination of the underlying mechanisms showed that sUV-activated MAPK signaling pathways are blocked by sulfuretin. Interestingly, sulfuretin directly inhibits the kinase activity of selected Src family. Because the amino acid sequence of Hck kinase which used kinase array is 230–497, it was assumed that sulfuretin interacts with this conserved domain of Src family kinase. It was also found that sulfuretin directly binds to sulfuretin with the lowest binding energy of −8.9 kcal/mol and free energy of −10.07 kcal/mol. Additionally, Hck protein was precipitated with sulfuretin-conjugated Sepharose 4B beads in HDFs cell lysate. Overall, present findings indicated that sulfuretin plays the role of anti-skin aging agent by acting as a general Src family kinase inhibitor in human skin.

We hypothesized that hepatic steatosis could be mitigated by the hypolipidemic activity of Schisandra chinensis berry ethanol extract (SCE) via the inhibition of histone acetyltransferase (HAT) activity. HepG2 cells treated with oleic acid (OA) in the presence of SCE exhibited reduced OA-induced lipid accumulation, which was likely mediated by reductions in SREBP-1c expression. SCE attenuated the acetylation of total lysine and H3K9 that was otherwise increased by OA. Male obese mice fed with either a low-fat diet or Western diet exhibited reduced body and liver weights when supplemented with 1% SCE. The SCE-mediated attenuation of hepatic lipid accumulation was accompanied by a decrease in the expression of lipogenic genes. SCE also attenuated the expression of acetylated lysine and non-acetylated forms of H3K9 acetylation in the livers of these mice. Taken together, these results suggest that SCE has potential for further development as a novel therapeutic agent for the prevention of steatosis.

Porphyrin(Por)–spiropyran(SP) hybrid compounds, including Por–SP dyad, Por–SP2 triad, and Por–SP4 pentad, were prepared and characterized by 1H NMR, MALDI-TOF MS and UV–Vis spectroscopies. Upon 350 nm UV irradiation of Por–SPn (n = 1, 2, 4) in dichloromethane, unusual red-shifted absorption spectra were observed with the colour change from pink into green. Probably due to the protonation of core nitrogens in porphyrin ring, their absorption maxima in dichloromethane were shifted from 418 (Soret band), 515, 550, 590, 645 (four Q bands) nm into 450 and 665 nm. Also, fluorescence maxima were also shifted from 650 and 715 nm to 692 nm. In the other hands, upon irradiation with 350 nm UV light in THF, the colour changed from pink into violet and absorption band at 590 nm increased and the fluorescence spectra showed the decrease of 650 and 715 nm bands and increase of 600–640 nm band, due to the normal ring-opening reaction of spiropyran moiety into merocyanine. In the dark, original absorption and fluorescence spectra were recovered very slowly in dichloromethane, but quickly in THF. The reversible photochromic reactions of Por–SPn (n = 1, 2, 4) in dichloromethane and THF were investigated by observing absorption and fluorescence spectral changes during UV irradiation or standing in the dark.

In this study, we performed in vitro and in vivo studies to examine whether a 70% ethanol extract of Prunus mume fruits (EMS) exhibits anti-diabetic effects. Treatment with EMS increased glucose uptake in C2C12 myotubes, and also increased PPAR-γ activity or PPAR-γ mRNA expression. To confirm these in vitro results, we next conducted an animal experiment. A high-fat diet significantly increased the body weight, fat accumulation, and glucose levels in mice. Under the same conditions, 5% EMS attenuated the high-fat diet-induced increase in body weight and fat accumulation and improved the impaired fasting glucose level and glucose tolerance. High performance liquid chromatography analysis demonstrated that EMS contained chlorogenic acid, caffeic acid, rutin, luteolin-7-glucoside, naringin, apigenin-7-glucoside, and hesperidin. Taken together, these findings suggest that EMS exerts an anti-diabetic effect both in vitro and in vivo, which is mediated, at least in part, by the activation of PPAR-γ.

Four 1-(9-anthryl)-2-heteroarylethene derivatives containing sulfur or oxygen atom such as 1-(9-anthryl)-2-(2-thiophenyl)ethene (ATE), 1-(9-anthryl)-2-(2-benzo[ b ]thiophenyl)ethene (ABTE), 1-(9-anthryl)-2-(2-furanyl)ethene (AFE), and 1-(9-anthryl)-2-(2-benzofuranyl)ethene (ABFE) have been prepared and their excited state properties have been investigated in cyclohexane, acetonitrile, and methanol. These sulfur- or oxygen-heteroaromatic ring derivatives show solvent-dependent fluorescence and photoisomerization behavior, due to the intramolecular charge-transfer character of the lowest S 1 state. Substituent effect on fluorescence and photoisomerization of ATE further supports the contribution of the intramolecular charge-transfer character to the lowest S 1 state, which is more increased by the introduction of electron-withdrawing substituent into anthracene ring.

The preparation and photophysics of organometallic Ir(III) complexes with 3-phenylpyridazine (H6Clppdz) and its derivative are reported. IrCl 3 · n H 2 O reacts with H6Clppdz, and 3-chloro-6-(3 ′ -methoxyphenyl)-4-methyl-pyridazine (MCOMppdz) to give the corresponding chloride-bridged dimers, (6Clppdz) 2 Ir( μ -Cl) 2 Ir(6Clppdz) 2 and (MCOMppdz) 2 Ir( μ -Cl) 2 Ir(MCOMppdz) 2 in good yields. These chloride-bridged dimers are cleaved with 2-pyrazinecarboxylic acid (Hpyzc), 2-picolinic acid (Hpic), acetylacetone (Hacac), and 2,2,6,6-tetramethyl-3,5-heptanedione (Htmd) to give the corresponding monomer, (6Clppdz) 2 Ir(pyzc), (6Clppdz) 2 Ir(pic), (6Clppdz) 2 Ir(acac), (6Clppdz) 2 Ir(tmd), (MCOMppdz) 2 Ir(acac), and (MCOMppdz) 2 Ir(tmd), respectively. The complexes show bright orange to red luminescence at room temperature and the emission wavelenghts are affected by the ancillary ligands as well as cyclometalating ligands (593–664 nm).

The fluorescence quenching of various substituted tetraphenylporphyrins and their zinc complexes by ruthenium(II) tris(2,2′-bipyridine) has been investigated in dichloromethane. While fluorescence quenching was not effective for free base porphyrins, but in the case of zinc porphyrins fairly efficient. Plots for the Stern–Volmer quenching constant versus the calculated free energy change (Δ G red ) for photoinduced oxidative electron transfer (ET) processes from the excited singlet porphyrins to ruthenium(II) tris(2,2′-bipyridine) were shown to be linear. Among porphyrins/ruthenium(II) tris(2,2′-bipyridine) pairs examined in this study, ZnTMeOPP/ruthenium(II) tris(2,2′-bipyridine) pair exhibited most efficient fluorescence quenching as predicted to carry out most favorable photoinduced oxidative electron transfer processes by the calculated free energy changes (Δ G red ).

The fluorescence properties and photoisomerization behavior for trans and cis isomers of 1-(9-anthryl)-2-(2-pyrazinyl)ethene (APzE). a diaza analogue of 1-(9-anthryl)-2-phenylethene (9-APE), were studied. The fluorescence maximum (λ 1 ). quantum yield ( Φ t ) and lifetime ( τ t ) of t -APZE were solvent-dependent reflecting the intramolecular charge transfer character in the lowest excited singlet state. However, in polar protic solvent, some discrepancy was observed probably due to protonation on the nitrogen atoms. The photoisomerization of t -APzE was observed even in very nonpolar solvent, in contrast that the parent t -9-APE did not photoisomerize in any solvent and photoisomerization of monoaza analogues t 1-(9-anthryl)-2-( n -pyridyl)ethenes ( n -APyE) was very inefficient in nonpolar solvent. The quantum yield of the trans → cis photoisomerization ( Φ t → c ) of t -APzE was also solvent-dependent. Not only the inverse dependence for Φ f -and Φ t → c , of t -APzE on the temperature and the solvent polarity but also hiacetyl-sensitized photoisomerization experiment indicate that the photoisomerization of t -APzE occurs, at least in part, via the excited singlet state. In air-saturated solution, another side photoproduct was observed in all solvent examined and identified as anthraquinone, a photo-oxidation product. For c -APzE, the τ t , is too short to measure and Φ t , is relatively low. Quantum yields of fluorescence and cis→trans photoisomerization of c -APzE in various solvent and temperature indicate singlet mechanism for the cis → trans photoisomerization of c -APzE in polar solvent but mixed singlet/triplet mechanism in nonpolar solvent. On irradiation of c -APzE, the photo-oxidation product was not generated at all in any solvent. In n -hexane, photocyclization competing with photoisomerization was observed both for t - and c -APzE.

The axial coordination of aza analogues of 1-(9-anthryl)-2-phenylethene to zinc 5,10,15,20-tetratolylporphyrin (ZnTTP) was investigated. E -1-(9-Anthryl)-2-( n -pyridyl)ethenes ( n = 2, 3 and 4) ( E - n -APyE), the Z isomers ( n = 2 and 4) ( Z - n -APyE) and E -1-(9-anthryl-2-(2-pyrazinyl)ethene ( E -APzE) were tested as aza analogues of 1-(9-anthryl)-2-phenylethene. E -2-APyE, Z -2-APy and E -APzE did not form a complex with ZnTTP. ZnTTP formed a complex with E -3-APyE, but complexation of ZnTTP with Z -3-APyE could not be observed because Z -3-APyE was not available. E -4-APyE and Z -4-APyE showed a considerable difference in their ability to form a complex with ZnTTP. In order to examine the effect of the solvent polarity, the results in dichloromethane were compared with those in toluene. The extent of coordination of E -4-APyE to ZnTTP in dichloromethane was significantly reduced due to the E → Z photoisomerization of E -4-APyE on UV irradiation. However, because the photoisomerization of E -4-APyE was very inefficient in toluene, the extent of coordination of E -4-APyE to ZnTTP in toluene remained unchanged on UV irradiation for up to 2 h. Therefore a change in solvent affected the photoresponsiveness of the system.

The quantum yields of fluorescence and photoisomerization of trans -1-(9-anthryl)-2-( n -pyridyl)ethenes ( n = 2, 3 or 4) (t n -ApyE) and the corresponding cis isomers ( n = 2 or 4) (c- n -APyE) were measured in various solvents. t-3-APyE is strongly fluorescent, but does not undergo photoisomerization, similar to trans -1-(9-anthryl)-2-phennylethene (t-9-APE). The fluorescence and photoisomerization of t-2-APyE and t-4-APyE are strongly influenced by the solvent polarity. In non-polar solvents, they show relatively strong fluorescence, but no photoisomerization to the corresponding cis isomers. As the solvent polarity is increased, the fluorescence intensity decreases and the photoisomerization to the cis isomer becomes efficient. An intramolecular charge transfer excited state is suggested to contribute to the photoisomerization. A singlet mechanism is proposed from the inverse relationship between the fluorescence and photoisomerization quantum yields over the range of solvent polarity and temperature used. A much weaker solvent effect was observed on the fluorescence and photoisomerization of c-2-APyE, and the fluorescence and photoisomerization of c-4-APyE were found to be independent of the solvent polarity. Efficient isomerization to the trans isomer was observed in both non-polar and polar solvents.

A molecular tetrad consisting of a free-base porphyrin (P) linked to a carotenoid polyene (C) and a diquinone moiety (Q A –Q B ) has been synthesized, and its photochemistry has been investigated using time-resolved techniques. Excitation of the porphyrin moiety of the tetrad in dichloromethane solution is followed by photoinduced electron transfer to yield an initial C-P + -Q − A –Q B state, which is formed with arate constant of 2.3×10 9 s −1 and a quantum yield of 0.87. In chloroform, the rate is 4.1×10 9 s −1 and the quantum yield is 0.94. Transient absorption studies show that this state evolves by subsequent electron transfer pathways to a final C + -P-Q A –Q − B charge-separated state whose lifetime is 7.4 μs in dichloromethane and 740 ns in chloroform. The quantum yield of the final state is 0.49 in dichloromethane and 0.57 in chloroform. The yield of the final state is substantially higher than that in a related, previously-reported tetrad in spite of the fact that the quantum yield of the initial C-P + -Q − A –Q B species is lower. This fact is interpreted in terms of the rates of charge-separation reactions relative to those of charge recombination. It is shown that yields of charge separation in multicomponent molecules may be altered in a predictable fashion using the basic tenets of electron transfer theory.

The photocycloaddition reaction of khellin with dimethylfumarate (DF) was investigated. The singlet excited state of khellin is efficiently quenched by DF without giving any cycloadduct. Azulene quenching and the effect of olefin concentration on the photocycloaddition quantum yield indicate that the photoreaction proceeds through a triplet excited state only. These results are further confirmed by the triplet sensitization of the photoreaction and the external heavy atom effects on the photoreaction quantum yield.

The photophysical properties of a 4t,5′-C 4 -cyclomonoadduct (F-2) of 8-methoxypsoralen (8-MOP) with thymidine were compared with those of 5,7-dimethoxycoumarin (DMC), 4t,5′-dihydropsoralen (DHP) and 8-MOP. The magnitudes of the fluorescence quantum yields are in the order DMC > DHP > F-2 > 8-MOP, which is exactly the opposite of the order for the temperature dependence of the fluorescence in ethanol. For DMC, DHP, 8-MOP and F-2 the ratios of the phosphorescence quantum yields to the fluorescence quantum yields are 0.056, less than 0.01, 0.68 and 5.6 and the phosphorescence lifetimes are 0.88 s, 0.88 s, 0.76 s and 1.2 s respectively, in ethanol at 77 K. The phosphorescence-to-fluorescence ratio increases sharply while the phosphorescence lifetime decreases by the external heavy-atom effect. At 77 K, the fluorescence maximum is very red shifted in isopentane compared with that in ethanol, and phosphorescence is not observed in isopentane. The solvent dependence of the fluorescence of the compounds is probably due to a change in the rate of internal conversion rather than to intersystem crossing.

The photophysical properties of 5(E)-styryl-1,3-dimethyluracil (5(E)-SDU) were investigated. The fluorescence quantum yield and the lifetime are low and short relative to those of the parent aromatic hydrocarbon; this is probably because of the contribution of the n,π* state to the fast radiationless decay. However, the fluorescence of 5(E)-SDU at room temperature is not significantly affected by the solvent polarity, the presence of salts or the pH. This observation indicates that the 1(n,π*) state lies above the lowest 1(π,π*) state and that the vibronic mixing between the two states is not extensive. The highly positive fluorescence and the fluorescence excitation polarization confirm that the lowest excited singlet state has the π,π* configuration. The strong temperature dependence of the fluorescence intensity may be due to the operation of the activated process of twisting in the first excited singlet state competing with flurescence, and the rotation barrier is estimated to be 3.0 kcal mol−1. The strong quenching of fluorescence intensity by ethyl iodide at room temperature may be indicative of inefficient intersystem crossing. Moreover, only very weak phosphorescence is detected at 77 K and its quantum yield is too low to estimate in either isopentane-ethyl ether (1:1, v/v) or ethanol, supporting the idea of inefficient intersystem crossing suggested by laser flash photolysis results. Therefore, the major radiationless process appears to be internal conversion including rotatory radiationless decay. From the relatively long phosphorescence lifetime and its highly negative polarization the lowest triplet state is considered to be the 3(π,π*) state.

The photolysis of a dilute acetonitrile solution of 5(Z)-styryl-1,3-dimethyluracil in the presence of oxygen gives the dehydrocylized product in 26.7% yield. Adding benzophenone to the 5(E)-styryl-1,3-dimethyluracil solution improved the yield of the photocyclization owing to the efficient E → Z photoisomerization due to benzophenone sensitization. Studies on the salt, sensitization and quenching effects on the photocyclization of the compound indicate that the photocyclization occurs from the lowest excited singlet (1π, π*) state of 5(Z)-styryl-1,3-dimethyluracil.

1,4,5,8-Tetraazaphenanthrene (TAP) has close-lying n,π* and π,π* singlet states and therefore shows very weak fluorescence (Φf = 0.001); laser flash photolysis indicated that it undergoes efficient intersystem crossing (Φisc = 0.95). The intensity of fluorescence of TAP increases on addition of sodium acetate because N-Na cation coordination elevates the lowest excited 1(n,π*) state to a higher energy. Because of mixing between the lowest excited 1(n,π*) state and 1(π,π*), TAP shows the heavy-atom effect, which is generally not observed in the pure 1(n,π*) state. Since the phosphorescence lifetime is relatively long (about 0.5 – 0.8 s) and the phosphorescence is negatively polarized, the lowest triplet state has the π,π* configuration. The photoreactivity of TAP is compared with the photophysical parameters of azaphenanthrenes.