Photosensitizers cause oxidative damages in various biological systems either directly or reactive oxygen species (ROS)-dependently under light. Especially, dietary photosensitizers are involved in deterioration of foods during processing, storage and transportation. Since the analyzing methods for ...
Photosensitizers cause oxidative damages in various biological systems either directly or reactive oxygen species (ROS)-dependently under light. Especially, dietary photosensitizers are involved in deterioration of foods during processing, storage and transportation. Since the analyzing methods for photosensitizing activity, however, have not been thoroughly studied, it might be an important task to develop the related protocols and to establish quantification of the activity for the activity. In the present study, the method for analyzing photosensitizing properties of different dietary photosensitizers was developed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide formazan (MTT-F), 2,3,5-triphenyl-2H-tetrazolium formazan (TP-F), and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium formazan (INT-F) formazans as a probe. Significant and quantitative decolorization of MTT-F, TP-F, and INT-F was observed in the presence of zinc protoporphyrin (ZnPP), protoporphyrin IX (PPIX), zinc phthalocyanine (ZnPC), riboflavin (RF), erythrosine B (EB), methylene blue (MB), and chlorophyll (CP) under light. Decolorization of the formazans occurred irradiation time, light intensity, and photosensitizer concentration-dependently. Among the formazans, TP-F was most sensitive to photosensitizers, followd by MTT-F. Degradation of the formazans by the photosensitizers did not occur in a dark condition. In addition, 5-aminolevulinic acid (5-ALA) and acridine did not affect photo-degradation of formazans. Photosensitizing properties of the currently-used compounds were also evaluated by two different methods using DCFH fluorescence probe for detecting ROS and using thiobarbituric acid (TBA) for TBA reactive substance from photosensitizing reactions. The photoactive compounds used in this study showed relatively consistent actions in 3 methods applied.
The oxidized and bleached formazan by photosensitizers did not show a reversibly- reduced reaction property by N-acetylcysteine and β-mercaptoethanol (up to 500 μM). Radicals of 2,2'-azino-bis(3-ethylbenzo thiazoline-6-sulphonic acid) (ABTS) and 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) induced decolorization of the formazans regardless of light condition; concomitant reduction of both radicals by the formazans were also observed. Hydrogen peroxide (up to 800 μM) did not cause obvious decolorization or recolorization of formazans used either, suggesting that the formazans were more reactive with Type I photosensitizers rather than ROS-dependent Type II photosensitizers. The LC MS/MS results indicated the formation of m/z –1 and –2 oxidized products from MTT-F.
The quantification of photosensitizing activity for the compounds and dietary pigments using PPIX nmol equivalent per mg unit was performed based on the formazan method currently-developed. The order of photosensitizing activity was ZnPP (1746) ≥ PPIX (1642) > ZnPC (1336) > EB (920) > MB (498) > RF (54.3) ≥ CP (42.6) in the analysis using MTT-F and ZnPP (1912) > PPIX (1638) > EB > (1139) > ZnPC (226) > MB (178) > MB (498) > CP (49.6) ≥ RF (35.1) in the TP-F based analysis. The present study indicated that formazan dyes are a reliable probe for the quantitative analysis of photosensitizing activities, and the formazan-based method developed here can be an useful tool for screening and evaluating photosensitizing properties of various compounds used in food, medical, and industrial purposes.
Biological activities and related mechanisms of curcumin, a major polyphenolic compound in turmeric, the rhizome of curcuma longa, have been extensively investigated. Since curcumin is poorly soluble in water, its biological actions are limited in most aqueous experimental systems. In this study, effects of polyvinyl alcohol (PVA), a dietary compatible vehicle, on the solubility, stability, cellular uptake and bioactivities of curcumin [a mixture of curcumin, demethoxy-curcumin (DMC), and bisdemethoxy-curcumin (BMC)] were investigated. Curcumin solubility was improved significantly by PVA and absorbance of curcumin solution was enhanced PVA concentration-dependently with its peak shift to shorter wavelength. Improved stability and enhanced scavenging activities of curcumin against nitric oxide and ABTS radical were observed significantly in the presence of PVA. Cytotoxic effects of curcumin on both HCT 116 colon cancer and INT-407 normal intestinal cells were also enhanced by PVA. PVA increased cellular uptake of curcumin concentration-dependently in INT-407 cells; curcumin level was 2 fold higher in the presence of 250 μg/mL PVA. The present results indicate that PVA could improve solubility and stability of curcumin, and changes in these chemical behaviors of curcumin in aqueous systems might enhance pharmacological efficacy of curcumin.
Turmeric pigments have been used as a coloring agent and functional ingredients. In this study, extraction properties and chemical stability of the pigments were evaluated in several preservative solutions containing NaCl, sucrose, and acetic acid. After 72 h infusion, the levels of proteins and polyphenols and antioxidant activity of the turmeric extracts in the solutions were less pronounced than those in water. Acetic acid (12%) was more efficient for extracting curcuminoids from turmeric than water, NaCl (20%), or sucrose (25%). Curcumin is the most abundant in all solutions. A relative yield of BMC was the highest in acetic acid, whereas that of curcumin was the highest in NaCl and sucrose. Curcuminoids were relatively stable in sucrose and acetic acid and BMC was the most stable. Stability of curcuminoid solution decreased according to increase of NaCl content; it was significantly enhanced in sucrose and acetic acid. The present results might be applied to processing and storage of turmeric-related products in the preservative agents.
Photosensitizers cause oxidative damages in various biological systems either directly or reactive oxygen species (ROS)-dependently under light. Especially, dietary photosensitizers are involved in deterioration of foods during processing, storage and transportation. Since the analyzing methods for photosensitizing activity, however, have not been thoroughly studied, it might be an important task to develop the related protocols and to establish quantification of the activity for the activity. In the present study, the method for analyzing photosensitizing properties of different dietary photosensitizers was developed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide formazan (MTT-F), 2,3,5-triphenyl-2H-tetrazolium formazan (TP-F), and 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium formazan (INT-F) formazans as a probe. Significant and quantitative decolorization of MTT-F, TP-F, and INT-F was observed in the presence of zinc protoporphyrin (ZnPP), protoporphyrin IX (PPIX), zinc phthalocyanine (ZnPC), riboflavin (RF), erythrosine B (EB), methylene blue (MB), and chlorophyll (CP) under light. Decolorization of the formazans occurred irradiation time, light intensity, and photosensitizer concentration-dependently. Among the formazans, TP-F was most sensitive to photosensitizers, followd by MTT-F. Degradation of the formazans by the photosensitizers did not occur in a dark condition. In addition, 5-aminolevulinic acid (5-ALA) and acridine did not affect photo-degradation of formazans. Photosensitizing properties of the currently-used compounds were also evaluated by two different methods using DCFH fluorescence probe for detecting ROS and using thiobarbituric acid (TBA) for TBA reactive substance from photosensitizing reactions. The photoactive compounds used in this study showed relatively consistent actions in 3 methods applied.
The oxidized and bleached formazan by photosensitizers did not show a reversibly- reduced reaction property by N-acetylcysteine and β-mercaptoethanol (up to 500 μM). Radicals of 2,2'-azino-bis(3-ethylbenzo thiazoline-6-sulphonic acid) (ABTS) and 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) induced decolorization of the formazans regardless of light condition; concomitant reduction of both radicals by the formazans were also observed. Hydrogen peroxide (up to 800 μM) did not cause obvious decolorization or recolorization of formazans used either, suggesting that the formazans were more reactive with Type I photosensitizers rather than ROS-dependent Type II photosensitizers. The LC MS/MS results indicated the formation of m/z –1 and –2 oxidized products from MTT-F.
The quantification of photosensitizing activity for the compounds and dietary pigments using PPIX nmol equivalent per mg unit was performed based on the formazan method currently-developed. The order of photosensitizing activity was ZnPP (1746) ≥ PPIX (1642) > ZnPC (1336) > EB (920) > MB (498) > RF (54.3) ≥ CP (42.6) in the analysis using MTT-F and ZnPP (1912) > PPIX (1638) > EB > (1139) > ZnPC (226) > MB (178) > MB (498) > CP (49.6) ≥ RF (35.1) in the TP-F based analysis. The present study indicated that formazan dyes are a reliable probe for the quantitative analysis of photosensitizing activities, and the formazan-based method developed here can be an useful tool for screening and evaluating photosensitizing properties of various compounds used in food, medical, and industrial purposes.
Biological activities and related mechanisms of curcumin, a major polyphenolic compound in turmeric, the rhizome of curcuma longa, have been extensively investigated. Since curcumin is poorly soluble in water, its biological actions are limited in most aqueous experimental systems. In this study, effects of polyvinyl alcohol (PVA), a dietary compatible vehicle, on the solubility, stability, cellular uptake and bioactivities of curcumin [a mixture of curcumin, demethoxy-curcumin (DMC), and bisdemethoxy-curcumin (BMC)] were investigated. Curcumin solubility was improved significantly by PVA and absorbance of curcumin solution was enhanced PVA concentration-dependently with its peak shift to shorter wavelength. Improved stability and enhanced scavenging activities of curcumin against nitric oxide and ABTS radical were observed significantly in the presence of PVA. Cytotoxic effects of curcumin on both HCT 116 colon cancer and INT-407 normal intestinal cells were also enhanced by PVA. PVA increased cellular uptake of curcumin concentration-dependently in INT-407 cells; curcumin level was 2 fold higher in the presence of 250 μg/mL PVA. The present results indicate that PVA could improve solubility and stability of curcumin, and changes in these chemical behaviors of curcumin in aqueous systems might enhance pharmacological efficacy of curcumin.
Turmeric pigments have been used as a coloring agent and functional ingredients. In this study, extraction properties and chemical stability of the pigments were evaluated in several preservative solutions containing NaCl, sucrose, and acetic acid. After 72 h infusion, the levels of proteins and polyphenols and antioxidant activity of the turmeric extracts in the solutions were less pronounced than those in water. Acetic acid (12%) was more efficient for extracting curcuminoids from turmeric than water, NaCl (20%), or sucrose (25%). Curcumin is the most abundant in all solutions. A relative yield of BMC was the highest in acetic acid, whereas that of curcumin was the highest in NaCl and sucrose. Curcuminoids were relatively stable in sucrose and acetic acid and BMC was the most stable. Stability of curcuminoid solution decreased according to increase of NaCl content; it was significantly enhanced in sucrose and acetic acid. The present results might be applied to processing and storage of turmeric-related products in the preservative agents.
주제어
#formazan photosensitizing activity curcuminoid stability preservative solution
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