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In this work, mao berry extract was tested to determine whether it could be a green alternative reducing agent in the indigo dyeing on cotton fabrics. Glucose and fructose, which are the main reduc...

The distribution of terpinen-4-ol (TP4ol) and DMPBD inclusion complexes with 2-hydroxypropyl-β-cyclodextrin (HPbCD) in human skin has been investigated using the TOF-SIMS technique. TP4ol and DMPBD have been found to be major components of Zingiber cassumunar Roxb. (Plai) oil extracted by steam distillation. The results mainly show accumulation of TP4ol and DMPBD inclusion complexes with HPbCD in the epidermis and dermis whereas these two compounds without cyclodextrin cannot penetrate into the epidermis. This approach can be expanded for investigation of anti-inflammatory action and relief of muscle pain.

Zingiber cassumunar Roxb. (Plai) is a medical plant widely cultivated in Asia and its essential oil has been reported for several biological activities, such as anti-inflammatory, anti-microbial and anti-oxidant effects. In this work, the essential oil was extracted from Plai by steam distillation with 0.32% yield. (E)-1-(3,4-dimethoxyphenyl) butadiene (DMPBD), (E)-1-(3,4-dimethoxyphenyl) but-3-ene-1-ol (compound D) and terpinen-4-ol were reported as the major components. The components of Plai oil were investigated by GC-MS. It was found that sabinene, terpinen-4-ol and DMPBD were detected as the major components for 23, 20 and 30%, respectively. The three types of beta-cyclodextrins (bCDs) i.e. beta-cyclodextrin (bCD), 2-hydroxypropyl-beta-cyclodextrin (HPbCD) and citric acid crosslinked beta-cyclodextrin (pbCD) were used to form the inclusion complexes with Plai oil to increase the aqueous solubility, selectivity and anti-analgesic properties. The ratio of CDs and plai oil was varied. The amount of terpinen-4-ol and DMPBD were detected by GC-MS. The results showed that terpinen-4-ol was fitted to bCD whereas HPbCD showed the highest selectivity of DMPBD. The pbCD presented the lowest selectivity both terpinen-4-ol and DMPBD. As the results, the different types of CDs showed the different selectivity for inclusion complex formation with major component in Plai oil. The separation of terpinen-4-ol and DMPBD can be done by using CD inclusion complexes. The anti-analgesic property of Plai oil and its complexes will be further studied.

Beta-cyclodextrin polymers (pbCD) cross-linked by epichlorohydrin (pbCDE) and citric acid (pbCDC) were prepared in this work. The inclusion complexes of pbCDE and pbCDC with curcumin and two commercial UV filters, 2-ethylhexyl-p-methoxycinnamate (EHMC) and 4-tert-butyl-4′-methoxydibenzoylmethane (DBM) were investigated. The UV absorption of these three compounds observed in water indicated that the water solubility of these three hydrophobic compounds increased. The amount of EHMC was higher in both pbCDE and pbCDC than curcumin and DBM, respectively. The photostability of these three compound inclusion complexes with pbCDE and pbCDC were also studied in water and ethylene glycol. It was found that the photostability of the three compounds improved upon formation of the inclusion complex with pbCDE in an aqueous and ethylene glycol solution. The acidity of the crosslink moiety effects to the inclusion complex formation and the photostability of the guests suggesting that more acidity of citric acid decreased the formation and stability of all guest compounds.

Excito-repellency activity of plant extracts have been increasingly studied as mosquito repellents. In this study, the crude extract of Andrographis paniculata was evaluated for its noncontact repellency, contact excitation (irritancy + repellency), and knockdown/toxicity response against five colonized mosquitoes; Aedes aegypti (L.), Aedes albopictus (Skuse), Anopheles dirus Peyton & Harrison, Anopheles epiroticus Linton & Harbach, and Culex quinquefasciatus Say (Diptera: Culicidae) using an excito-repellency assay system under laboratory-controlled conditions. The escape responses were observed at four different concentrations (0.5–5.0% w/v) with A. paniculata showing strong spatial repellency against Ae. albopictus (96.7% escape) and Ae. aegypti (71.7% escape) at the 2.5% and 0.5% concentrations, respectively. At 0.5% and 5.0% concentrations, the greatest repellency was seen for An. dirus (48.2% escape) and Cx. quinquefasciatus (59.7% escape), respectively. Comparatively, low repellency action was observed against An. epiroticus (1.6–15.0% escape). Escape in contact assays (before adjustment) was generally less pronounced compared to noncontact spatial repellency, with Ae. albopictus showing highest percent escape (71.4% escape) in the contact assay at 1.0% concentration. After adjusting for spatial repellency, escape due to contact irritancy alone was either not present or an insignificant contribution to the overall avoidance response for all species. No knockdown or mortality at 24-h postexposure was observed in any trials. These findings indicate that the A. paniculata crude extract is more active against day-biting mosquitoes; however, this may be a reflection of the time of testing. This study demonstrates compelling evidence that A. paniculata extract performs primarily as a spatial repellent. Further investigations exploring the use A. paniculata as a potential active ingredient in repellent products are needed.

In this work a new system nanocarrier consisting of chitosan (CS) and beta-cyclodextrin crosslinked citric acid (pbCD) was prepared. Curcumin (cur), which is well-known for having a wide range of biological properties suitable for the treatment of several diseases, was selected as a model for forming the inclusion complex in pbCD and then encapsulated into CS nanoparticles (CSpbCD-cur). The effects of both the concentration of pbCD-cur and the pH were investigated. The CSpbCD-cur nanoparticles were characterised by SEM, FT-IR, DLS, drug loading and in vitro release. The results showed that the size of CSpbCD nanoparticles were unstable at higher pH values (pH ≥ 6) and pbCD concentrations. Moreover, the loading efficiency of the inclusion complex of curcumin with pbCD (pbCD-cur) entrapped into the CS nanoparticles (CSpbCD-cur), increased when the pbCD-cur concentration was increased. The size and size distritution (PDI) of nanoparticles showed the best at the concentration of pbCD-cur 20 mL/mg (with 1.5 mg/mL of CS) at pH 4. The release profile showed that CSpbCD-cur had a slower release than free curcumin resulting in that the cytotoxicity of CSpbCD-cur was less than that of pbCD-cur, and free curcumin, respectively.

Photoinduced electron transfer, chemical stability, and redox property of diruthenium−viologen complexes were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. Target systems include a series of diruthenium and viologen complexes consisting of Ru(bpy)3-viologen-Ru(bpy)3; Ru–V–Ru, Ru(bpy)3-viologen-Ru(bpy)(dcbpy)2; Ru–V–RuCOOH, and Ru(bpy)3-viologen-viologen-Ru(bpy)3; Ru–V–V–Ru, where bpy = 2,2′-bipyridyl and dcbpy = 4,4′-dicarboxyl-2,2-bipyridyl. The B3LYP functional was used to investigate the ground state properties for the three diruthenium and viologen complexes and for two parent complexes: ruthenium-bipyridine (Ru(bpy)32+) and methyl viologen (MV2+) as well as their oxidized states. Singlet excited states were examined using the TD-DFT calculations with CAM-B3LYP functional in acetonitrile using conductor polarizable continuum model (CPCM). The TD-DFT calculations reproduced the experimentally observed variation of the absorption spectra due to oxidation states. The correlation between the calculated UV–Vis transition and molecular orbitals for the excited state clearly established that the viologen dication (V2+) changed their reductive product into the radical cation (V•+) and neutral (V0), whereas ruthenium retained its formal Ru(bpy)32+ oxidation state. The metal to ligand charge transfer state of Ru(bpy)32+ was shown to undergo electron transfer quenching by methyl viologen dication (MV2+). These findings are relevant for the development of novel optoelectronic materials owing to a combination of chemical stability, redox activity, and long-lived excited states.

The water-soluble inclusion complexes of curcumin, 2-ethylhexyl-4-methoxycinnamate (EHMC) and 4-tert-butyl-4′-methoxydibenzoylmethane (DBM) with gamma-cyclodextrin polymer (pyCD) were successfully prepared and characterized by 1H-NMR, IR and UV–Vis spectroscopies. The water-solubility of EHMC–pyCD, DBM–pyCD and curcumin–pyCD was dramatically increased because of the water-soluble pyCD. The mole ratio of gamma-CD in pyCD to EHMC, DBM and curcumin were carried out as 1:1. The photostability of all inclusion complexes was investigated in water and ethylene glycol and compared with free active ingredients. It was found that the photostability of EHMC–pyCD was greatly enhanced whereas those of DBM–pyCD and curcumin–pyCD in water were decreased due to the acceleration of the photodegradation reaction inside the gamma-CD cavity. These results were able to be used as a solubilizer for cosmetic and also pharmaceutical applications.

Four unsymmetric dinuclear ruthenium and osmium complexes, Os(bpy) 3 -viologen-Ru(bpy) 3 ( 1 ; bpy = 2,2′-bipyridyl), Ru(bpy) 3 -viologen-Ru(bpy)(dcbpy) 2 ( 2 ; dcbpy = 4,4′-dicarboxyl-2,2-bipyridyl), Os(bpy) 3 -viologen-Ru(bpy)(dcbpy) 2 ( 3 ) and rotaxane 1⊂CB[7] (CB[7] = cucurbit[7]uril), were successfully synthesized. The NMR, electrochemistry and photochemistry studies of these complexes were performed in non-aqueous solutions. The results show that the CB[7] host mainly locates at the butyl linker part of the osmium side in an acetonitrile solution. This binding lowers the oxidation potential of osmium whereas the oxidation potential of ruthenium does not change. The oxidation potential of ruthenium in complexes 2 and 3 is higher due to the electron withdrawing property of carboxylic anchor groups. Analysis with UV–vis spectra shows the viologen radical formation and reversed process of these complexes in non-aqueous solutions.

Twelve monoazo disperse dyes were synthesized and then characterized by melting point (m.p.) measurement, elemental analysis and1H-NMR. The photostability of monoazo disperse dyes in solvents with different polarities was evaluated thereafter the dyes in each solvent were irradiated with visible light for 8 hours. The percentage of photostability of the dye decreased from the initial value in the range of 5-10%. The photostability was affected by the substituted group of the dyes regardless of the solvent used. Different R1group on the diazo component increased the photostability in order of H˃CN˃Cl. The photostability of the dye was also higher when R2group on the coupling component was a methyl group.

While fluorescent analogues of the canonical nucleobases have proven to be highly valuable in a large number of applications, up until today, fluorescent DNA base analogues remain virtually inapplicable for single-molecule fluorescence experiments which require extremely bright and photostable dyes. Insight into the photodegradation processes of these fluorophores is thus a key step in the continuous development towards dyes with improved performances. Here, we show that the commercially available fluorescent nucleobase analogue tC under intense long-term illumination and in the presence of O2 is degraded to form a single photoreaction product which we suggest to be the sulfoxide form of tC. The photoproduct is characterized by a blue-shifted absorption and a less intense fluorescence compared to that of tC. Interestingly, when tC is positioned inside double-stranded DNA this photodriven conversion of tC to its photoproduct greatly reduces the duplex stability of the overall double helix in which the probe is positioned. Since tC can be excited selectively at 400 nm, well outside the absorption band of the natural DNA bases, this observation points towards the application of tC as a general light-triggered switch of DNA duplex stability.

The main goal of this work was to study the possibility of improving the natural dye uptake and their fastness properties on cotton fabrics by the application of monochlorotriazine-β- cyclodextrin (MCT-β-CD). Hence, MCT-β-CD was synthesized, characterized, and grafted on cotton fabrics via pad and cure method. The existence of MCT-β-CD on cotton fabrics was confirmed by nitrogen content (%N). Natural dyes used were colorants extracted from turmeric and cassumunar powders, and a commercial natural dye i.e. Natural Red Brown. The commercial one was water soluble whereas the extracted dyes were sparingly soluble in water. These natural dyes were applied on cotton by pad-dry method. The extracted dyes on MCT-β-CD treated cotton fabrics gave higher visual color yield (K/S) than the untreated ones. In contrast, a commercial natural dye exhibited lower color yield on the treated fabrics because of its water soluble nature. The color fastnesses of the natural dyes on the treated cotton fabrics were improved from the untreated cotton samples.

The synthesis of two supramolecular diruthenium complexes, 1⊂CB[7] and 1⊂CB[8] (CB[n]=cucurbit[n]uril), which contain the respective host CB[7] and CB[8], were synthesized and isolated. In the case of host CB[8], the desired supramolecular complex was obtained by utilizing dihydroxynapthalene as a template during the synthesis. The (1)H NMR spectra, electrochemistry, and photochemistry of these supramolecular complexes were performed in nonaqueous solution. The results show that both CB[7,8] hosts mainly bind to the linker part in solution in acetonitrile. This binding also lowers the oxidation potential of the ruthenium metal center and hinders the quenching effect by the viologen moiety. It has also been shown that external methylviologen can be included into 1⊂CB[8]. Analysis with NMR spectroscopy, electrochemistry, and photochemistry clearly shows a viologen radical dimer formation between the bound viologen and free methylviologen, thereby showing that the unique abilities of the CB[8] host can be utilized even in nonaqueous solution.

Various cyclodextrins, alpha, beta and gamma, were esterified with 4-methoxy-, 2,4,5- and 2,4,6-trimethoxycinnamic acids. Upon esterification with β-cyclodextrin, the photostability of 2,4,5-trimethoxycinnamate increased while no improvement was observed for 4-methoxycinnamate and 2,4,6-trimethoxycinnamate. However, increase in the photostability of 4-methoxycinnamoyl moiety could be observed when esterified with α-CD and that of 2,4,6-trimethoxycinnamoyl moiety could be observed after being esterified with γ-CD. These photostability data together with the 2D NMR analyses indicated that the 4-methoxycinnamoyl, 2,4,5-trimethoxycinnamoyl and 2,4,6-trimethoxy cinnamoyl moieties could enter the α-CD, the β-CD, and the γ-CD cavities, respectively.

The photophysical properties of five methoxy-substituted 2-ethylhexylcinnamates were studied with experimental and theoretical methods. It was found that the fluorescence quantum yields varied strongly with the substitution pattern of the phenyl ring. A methoxy substitution at the meta position gave strong fluorescence, whereas the para substituted compounds were strongly quenched. This observation could be correlated to corresponding changes in the UV absorption spectra; the two lowest pipi* states were split for the meta-methoxy substituted cinnamate but almost degenerate for the para compound. Semi-empirical quantum mechanical calculations confirmed both the observed state order and the difference in the experimentally determined activation energies for non-radiative decay. This "meta-effect" was also preserved in the trimethoxy-substituted compounds, 2-ethylhexyl-2,4,5- and 2,4,6-trimethoxycinnamate, resulting in strong fluorescence and relatively high barrier for non-radiative decay in the former and weak fluorescence and relatively low barrier for non-radiative decay in the latter. The obtained information shows how the performance of the commercial sunscreen agent, 2-ethylhexyl-para-methoxycinnamate (OMC) might be improved.

Nanosilicon is currently under intensive research owing to its extremely promising properties, particularly in photonics domain. However, the photoluminescence (PL) mechanism of silicon nanocrystal remains unclear. We propose, in this paper, a simple method to investigate the PL properties of silicon nanoparticles by exposing the nanoparticles directly to the solvents. The interaction between the nanoparticles and different solvents allows us to assume that not only the quantum size effect but also the surface defect states play a critical role in the PL mechanism, especially at high energy region. This can be confirmed by the results of Transmission Electron Microscopy, FTIR and Raman Spectroscopy.

Photophysical properties and photochemistry of various substituted cinnamates and cinnamic acids for ultraviolet B blocking were investigated experimentally and theoretically. This series includes monohydroxy, -nitro, and -fluoro derivatives. The absorption spectra were satisfactorily reproduced by the direct SAC-CI method with respect to the peak position and intensity. The transition character of the low-lying two ππ* and σπ* states for these 18 derivatives was analyzed. The para derivatives have a different transition character of the ππ* transitions compared with those of the ortho and meta derivatives. To elucidate the relaxation mechanism, the emission spectra were observed with oxygen quenching and the photostability was examined experimentally. The calculated radiative lifetimes indicate that the ortho- and meta-substituted derivatives have longer lifetimes for emission than the para derivatives. The potential energy curves of the first and second singlet excited states of the hydroxy derivatives as well as the vertical singlet and triplet transitions were examined to investigate the relaxation qualitatively. The ortho and meta derivatives have an energy barrier or flat surface in S1 resulting in fluorescence, whereas the para derivatives show nonradiative decay without an energy barrier. The para-hydroxy derivative was found to be an excellent UV absorber based on its broad absorption in the UVB/UVA regions, less emission, and higher photostability.

A traditional reducing agent in an indigo dyeing process with cotton fabrics is sodium dithionite (Na 2 S 2 O 4 ) which is environmentally unfavorable because the resulting by-products cause various problems to the disposal wastewaters. In this research, glucose was used as a possible replacement of Na 2 S 2 O 4 in indigo dyeing. The comparison of reduction power of Na 2 S 2 O 4 and glucose for natural indigo dyeing on cotton fabrics based on reduction potential was analyzed. The optimum reduction temperature for natural indigo dye of both reducing agents was at 70°C. The reduction time did not have a significant effect on the reduction potential under the condition studied. Na 2 S 2 O 4 could give higher color strength than glucose. However, wash fastness of the fabric samples from a glucose reduction was slightly better than Na 2 S 2 O 4 ones. Hence, glucose virtually has a potential to be used as a green reducing agent in natural indigo dyeing.

The absorption and emission spectra of ultraviolet B (UVB) blocking cinnamate derivatives with five different substituted positions were investigated using the symmetry-adapted cluster configuration interaction (SAC-CI) method. This series included cis- and trans-isomers of ortho-, meta-, and para-monomethoxy substituted compounds and 2,4,5-(ortho-, meta-, para-) and 2,4,6-(ortho-, para-) trimethoxy substituted compounds. The ground and excited state geometries were obtained at the B3LYP/6-311G(d) and CIS/D95(d) levels of theory. All the compounds were stable as cis- and trans-isomers in the planar structure in both the S(0) and S(1) states, except the 2,4,6-trimethoxy substituted compound. The SAC-CI/D95(d) calculations reproduced the recently observed absorption and emission spectra satisfactorily. Three low-lying excited states were found to be relevant for the absorption in the UV blocking energy region. The calculated oscillator strengths of the trans-isomers were larger than the respective cis-isomers, which is in good agreement with the experimental data. In the ortho- and meta-monomethoxy compounds, the most intense peak was assigned as the transition from next highest occupied molecular orbital (next HOMO) to lowest unoccupied molecular orbital (LUMO), whereas in the para-monomethoxy compound, it was assigned to the HOMO to LUMO transition. This feature was interpreted as being from the variation of the molecular orbitals (MOs) due to the different substituted positions, and was used to explain the behavior of the excited states of the trimethoxy compounds. The emission from the local minimum in the planar structure was calculated for the cis- and trans-isomers of the five compounds. The relaxation paths which lead to the nonradiative decay were also investigated briefly. Our SAC-CI calculations provide reliable results and a useful insight into the optical properties of these molecules, and therefore, provide a useful tool for developing UVB blocking compounds with regard to the tuning of the photoabsorption.