• Journal of the Korean Chemical Society
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• v.27 no.3
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• pp.213-217
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• 1983

Devices that mimic the natural photosynthetic pathway are of considerable interest as fuel sources. Quantum yield of viologen radical formation in several water-in-oil microemulsion system were measured. The yield of hexadecylviologen radical formation in microemulsion system using EDTA as an electron donor, ruthenium bipyridinium complex as photosensitizer, and hexadecylviologen as an electron acceptor was 12%. When benzylnicotinamide was inserted in the interface of the microemulsion and azo compound was dissolved in oil face, the quantum yield of hydroazo compound was 0.16. Organic dye (Rose bengal) was used as photosensitizer for the photoinduced electron transfer reaction. In anionic microemulsion no electrontransfer was observed.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.6-13
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• 1997

Reactivity and reaction mechanism for the photosensitized generation of hydroxyl radical by various coumarin derivatives are investigated by means of ESR and laser flash photolysis methods. The nine kinds of coumarin derivatives show to be proceeded through the OH·radical generation mechanism, however 1-ethyl-3-nitro-1-nitrosoguanidine decomposes and produces the carbene intermediate before OH·radical generation reaction occurs. The nine coumarin derivatives show the signals, which are corresponded to DMPO-OH spin adducts. NaN3, EtOH and HCOONa act as a strong photosensitizer to quench OH·radical. The decay rate constants of the hydrated electrons in the case of added N2O show higher than added K3Fe(CN)6.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.32-39
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• 2024

This study evaluated the additive impact of ethylenediamine tetraacetic acid (EDTA) on erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) biofilm by measuring colony-forming units and applying confocal laser scanning microscopy. Fifty-six bovine incisors, free from dental caries or structural defects, were utilized in this study. Dentin specimens were created by cutting with a low-speed diamond disk under a continuous flow of water, resulting in dimensions of 6.0 mm × 3.0 mm × 2.0 mm. The specimens were categorized into 4 groups: Control, EDTA, PDT, and EDTA + PDT. S. mutans ATCC 25175 was employed to establish biofilm on the dentin specimens. A 17% EDTA solution was applied for 1 min. For PDT, erythrosine served as the photosensitizer. Finally, a light-emitting diode source (385 - 515 nm) was employed in this study. The PDT group exhibited a significantly lower bacterial count than both the control and EDTA groups (p < 0.001). The EDTA + PDT group demonstrated a significantly reduced bacterial count compared to the other 3 groups (p < 0.001). This study demonstrated that EDTA enhances the antimicrobial efficacy of PDT on S. mutans biofilm. Even at a low concentration of photosensitizer, the combination of EDTA and PDT yields a significant antibacterial effect.

• Journal of Life Science
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• v.25 no.1
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• pp.53-61
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• 2015

In this study, we tried to separate the photosensitizer that induces apoptosis of leukemia cells (U937) from perilla leaves. Perilla leaves (Perilla frutescens Britt var. japonica Hara) are a popular vegetable in Korea, being rich in vitamins (A and E), GABA, and minerals. Dried perilla leaves were extracted with methanol to separate the photosensitizer by various chromatographic techniques. The structure of the isolated compound (PL9443) was identified by 1D-NMR, 2D-NMR, and FAB-mass spectroscopy. Absorbance of the UV-Vis spectrum was highest at 410 nm and was confirmed by the 330, 410, and 668 nm. PL9443 compound was determined to be pheophorbide, an ethyl ester having a molecular weight of 620. It was identified as a derivative compound of pheophorbide structure when magnesium comes away from a porphyrin ring. Observation of morphological changes in U937 cells following cell death induced by treated PL9443 compound revealed representative phenomena of apoptosis only in light irradiation conditions (apoptotic body, vesicle formation). Results from examining the cytotoxicity of PL9443 substance against U937 cells showed that inhibition rates of the cell growth were 99.9% with the concentration of 0.32 nM PL9443. Also, the caspase-3/7 activity was 99% against U937 cells with the concentration of 0.08 nM of PL9443 substance. The result of the electrophoresis was that a DNA ladder was formed by the PL9443. The PL9443 compound is a promising lead compound as a photosensitizer for photodynamic therapy of cancer.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.47-53
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• 1999

Photosensitizing activities of some photosensitizers (PS) for the artificial diminution of pesticide residues on horticultural crops were investigated. Five fungicides, iprodione, bitertanol, chlorothalonil, myclobutanil, and dichlofluanid were sprayed on apple and cucumber, followed by the application of each selected photosensitizer, and the samples were collected 0, 1, 3, 7, 15 days after the photosensitizer application and analyzed for the residual amounts. Of the 40 photosensitizers tested, six selected on the basis of the eliminating effect of pesticide residues were PS-1 (aromatic ketone), PS-2 (aromatic amine), PS-3 (quinone), PS-4 (inorganic compound), PS-5 (organic acid salt), and PS-6 (semiconductor photocatalyst). The residual amount of iprodione after 15 days of the application of PS-1 was 74% of that of the control. For bitertanol, the residual amount after 15 days of the application of PS-1 accounted for 78% of that of the control. The residual amounts of chlorothalonil after 1 day of the application of PS-1 and PS-2 accounted for 56 and 54% of those of the control, respectively. The residual amounts of iprodione on cucumber after 3 days of the application of the photosensitizers PS-1 and PS-2 were 44 and 67% of those of the untreated control, respectively. For myclobutanil, the residual amount after 15 days of the application of PS-6 accounted for 45% of that of the control. In case of dichlofluanid, the residual amount after 3 days of the application of PS-1 accounted for 44% of that of the control. Based on the results, PS-1 turned out to be the most promising photosensitizer for the accelerated photodegradation of the above fungicides on apple and cucumber.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.599-605
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• 2016

Recently, photodynamic and photothermal therapies have received increasing attention as an effective cancer treatment. In this study, a gold nanorod (AuNR) colloidal solution was synthesized as a hyperthermia agent for photothermal therapy and also modified with photosensitizer (PS) for photodynamic therapy. PEG (polyethylene glycol) and FA (folic acid) ligand were also introduced into AuNR for the long circulation in human body and efficient targeting of cancer cells, respectively and AuNRs were modified with FA-PEG and poly-${\beta}$-benzyl-L-aspartate (PBLA) block copolymers through a 3,4-dihydroxy hydrocinnamic acid (HCA) linker. A series of AuNRs with various aspect ratios were synthesized by controlling the feeding ratio of $AgNO_3$. The physicochemical property and morphology of synthesized AuNR100 and FA-PEG-$P(Asp)_{50}$-HCA-AuNR100 were analyzed by UV-visible spectrophotometer, $^1H$ NMR, XPS measurements, TEM. The surface modified AuNR carrier with biocompatibility could be applied for the effective diagnosis as well tumor phototherapy.

• Journal of Life Science
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• v.28 no.11
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• pp.1321-1331
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• 2018

The aim of this study was to separate the photosensitizer that induces apoptosis of U937 and SK-HEP-1 cells from Nostoc commune. Dried N. commune was extracted with $CH_2Cl_2/MeOH$ (1:1) to separate the photosensitizer using various chromatographic techniques. The isolated compound was identified as pheophytin a ($C_{55}H_{74}N_4O_5$) with a molecular weight of 870. Its photodynamic activities were assessed under different irradiation conditions (light and non-light) at the same concentration range of $1.15-23.0{\mu}M$. The apoptosis inducing activity in U937 or SK-HEP-1 cells appeared only in the light. The mechanisms underlying the pheophytin a-mediated photodynamic inhibition of cancer cells were further investigated by examining cell morphology changes, cytotoxicity, caspase-3/7 activity, fluorescence staining, flow cytometry analysis, and DNA fragmentation in these two cell lines. The positive control and the light irradiation group showed typical apoptotic responses, including morphological changes, cytotoxicity, caspase activity, nucleus shrinkage owing to chromatin condensation, DNA laddering, and the presence of apoptotic bodies. Cytotoxicity markedly increased in a dose-dependent manner after a 12 hr exposure. Caspase-3/7 activity was higher in U937 cells than in SK-HEP-1 cells. Apoptosis induction therefore appeared to be both concentration- and light-dependent. In conclusion, pheophytin a, isolated from the blue green alga N. commune, had a photodynamic apoptosis-inducing effect on U937 and SK-HEP-1 cells. The findings reported here can be used as basic data for the development of next-generation photosensitizers from N. commune.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4109-4112
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• 2011

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3095-3098
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• 2012

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.983-984
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• 2014