Loading...
Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267

Contents lists available at ScienceDirect

Journal of Photochemistry and Photobiology B: Biology journal homepage: www.elsevier.com/locate/jphotobiol

Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity Chien-wei Cheng, Liang-yü Chen, Chan-wei Chou, Ji-yuan Liang ⇑ Department of Biotechnology, Ming-Chuan University, Gui-Shan 33343, Taiwan

a r t i c l e

i n f o

Article history: Received 27 January 2015 Accepted 30 April 2015 Available online 8 May 2015 Keywords: Superoxide dismutase LED Blue light NBT Riboflavin

a b s t r a c t Determination of the superoxide dismutase activity is an important issue in the fields of biochemistry and the medical sciences. In the riboflavin/nitro blue tetrazolium (B2/NBT) method, the light sources used for generating superoxide anion radicals from light-excited riboflavin are normally fluorescent lamps. However, the conditions of B2/NBT experiments vary. This study investigated the effect of the light source on the light-excitation of riboflavin. The effectiveness of the photolysis was controlled by the wavelength of the light source. The spectra of fluorescent lamps are composed of multiple colour lights, and the emission spectra of fluorescent lamps made by different manufacturers may vary. Blue light was determined to be the most efficient for the photochemical reaction of riboflavin in visible region. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. A blue light is better than a fluorescent lamp for the photo-decomposition of riboflavin. The performance of the B2/NBT method is thereby optimized. Ó 2015 Elsevier B.V. All rights reserved.

1. Introduction Superoxide dismutase (SOD) is essential to many living organisms. This enzyme is one of the most important antioxidant defence mechanisms in microorganisms and plant cells that are exposed to oxygen [1]. The antioxidant capacity of natural ingredients is also a significant issue for foods with special dietary purposes [2]. SOD, as a free radical scavenger, can convert superoxide anion radicals (O 2 ) into H2O2 and O2 in living cells. By scavenging O 2 , the oxidation of lipid membranes can be prevented [3]. Superoxide anion radicals are intermediate products generated during oxidation or reduction. Formed from hydroxyl radicals or hydroxyl peroxide compounds, O 2 causes damage, inflammation, atherosclerosis and aging of cells [4,5]. Hence, the determination of SOD activities, either in vivo or in vitro, is an important topic in the fields of biochemistry and the medical sciences. Many methods, both direct and indirect, have been developed for the determination of SOD activity. However, direct assays for SOD determination are scarce because of their need for special apparatus, such as an electron paramagnetic resonance spectrometer (EPR). Indirect assays relying on the ability of SOD to inhibit O 2 -driven reactions are more widely applied in biochemical ⇑ Corresponding author. Tel.: +886 3 3507001x3772; fax: +886 3 3593878. E-mail address: [email protected] (J.-y. Liang). http://dx.doi.org/10.1016/j.jphotobiol.2015.04.028 1011-1344/Ó 2015 Elsevier B.V. All rights reserved.

laboratories [6]. Beyer and Fridovich [7] investigated the effects of experimental variables on two indirect assays, the xanthine oxidase and cytochrome C method and the riboflavin/nitro blue tetrazolium method (B2/NBT). The B2/NBT method is considered simpler and is preferred for the quantification of SOD activity in crude extracts [7]. Riboflavin, also known as vitamin B2, is very sensitive to light. It decomposes after being irradiated by ultraviolet (UV) or visible light (420–560 nm) for a very short time [8], generating free radicals of reactive oxygen species (ROS), such as O 2 and singlet oxygen [9]. The riboflavin photochemical treatment with blue light can be employed to inactivate E. coli with generated ROS [10,11]. Superoxide anion radicals generated from light-excited riboflavin can be utilized to examine the effect of luminance on light reactions of nitro blue tetrazolium (NBT) [5]. In this study, NBT is used as an indicating scavenger to be reduced by O 2 . NBT reduction causes an increase in the absorbance at 560 nm in a process that may be inhibited by SOD. In addition, the B2/NBT method can be employed to evaluate the contents of phenolic compounds in functional foods through ROS scavenging. In the B2/NBT method, the light sources used for generating O 2 from light-excited riboflavin are normally fluorescent lamps. A fluorescent lamp is excited to generate ultraviolet rays by a low-pressure mercury vapour and argon. The inner wall of a glass tube is coated with a fluorescent substance and stimulated by ultraviolet rays to generate a hybridized visible light. However,

C.-w. Cheng et al. / Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267

the conditions and apparatuses for the B2/NBT experiments varied in the studies reviewed. The fluorescent lamps used were of different specifications, including 13 W [1], 15 W [12,13], 20 W [7,14], 25 W [15], 30 W [16] and 40 W [17], and were illuminated over different distances and for different durations. The reactions were initiated by adding riboflavin at 2000 [18], 3000 [19], 4000 [20] and 5000 lux [21] for the luminance of fluorescent lamps. The effects of light source properties, such as colour and wavelength, on the light-excitation of riboflavin have been investigated using the B2/NBT assay [22]. The fluorescent lamp is excited to generate a hybridized visible light comprised of multiple colour lights. Thus, the properties of the light source could affect the riboflavin photochemistry, leading to incorrect conclusions from the B2/NBT assay. To ensure high accuracy, the widely accepted B2/NBT assay for the quantification of SOD activity has to be validated. The current study developed an effective SOD assay from the B2/NBT method by applying a well-defined light source to riboflavin photochemical reactions. The goal was to investigate the effects of light quality on the light-excitation of riboflavin as assayed by the B2/NBT method. The results thus obtained would promote the consistency of enzymatic measurements using photolysis reactions. 2. Materials and methods 2.1. Setup of illumination units The photo-induced reactions were performed in a plastic box (104 cm  74 cm  55 cm) with a light source. The box was made of white cardboard, and its outer surface was covered with black cloth. Three light-emitting diode (LED) tube lights (580 mm length) in red, green and blue (VITALUX T8HO LED tube lights, Vita LED Technologies Co., Tainan, Taiwan) and two fluorescent lamps, Fluor-A (38 W, FHF38WEX, Taiwan Fluorescent Lamp Co., Taipei, Taiwan) and Fluor-B (30 W, FCL30D/28, China Electric MGF. Co., Taipei, Taiwan), were used as light sources. Irradiance was measured by the power of the electromagnetic radiation per unit area (mW/cm2) with radiometry and validated by a solar power meter (TM-207, Tenmars Electronics Co., Taipei, Taiwan). Luminance, a term used in photometry, was measured in lux (lx) or lm/m2 by a digital light meter (YF-170, Tenmars Electronics Co., Taipei, Taiwan).

263

Fig. 1. Visible spectra of fluorescent and LED lamps used in this study.

The riboflavin (2.4 lM in 50 mM, pH 7.8 phosphate buffer) was irradiated by the fluorescent lamps and LED tube lights at 1.0 mW/cm2 for 20 min. The absorbance of the illuminated riboflavin was detected at 200–800 nm by a UV/vis spectrometer (Lambda35, Perkin-Elmer). 2.4. Effects of light sources on the generation of O 2 with the B2/NBT method The reduction in NBT was determined using the method developed by Beauchamp and Fridovich [24]. All solutions were 50 mM in phosphate buffer (pH 7.8). 3 mL of reactant was used, and the concentrations of riboflavin, methionine and NBT were 2.4  106 M, 0.01 M and 1.6  104 M, respectively. The distance between the reactant and the lamps was fixed, and the irradiance was controlled. The reactant was illuminated by blue, green, yellow or red LED irradiation at 1.0 mW/cm2, by the fluorescent lamps at 1.0 mW/cm2, and by the blue light irradiation at 0.1 mW/cm2 for 10, 20 or 30 min. For the control treatment, the reactant was kept in the dark. The photo-chemically reduction of riboflavin generated O 2 , which reduced NBT to form blue formazan, which can be detected at 560 nm (Lambda35, Perkin-Elmer). 2.5. Effects of light source on O 2 scavenging activity using gallic acid

2.2. Chemicals Gallic acid, l-methionine, monopotassium phosphate, potassium dihydrogen phosphate, riboflavin and SOD (S9697-15KU) were purchased from Sigma–Aldrich (St. Louis, MO). The SOD was assayed by Sigma–Aldrich using the xanthine oxidase/cytochrome C method [23]. Nitro blue tetrazolium (NBT) was purchased from Bio Basic, Inc. (Markham, Ontario, Canada). Ultra-pure deionized water from a Milli-Q system was used as a solvent in this study.

Gallic acid was employed to determine the effects of the light source on the O 2 scavenging activity using the B2/NBT method described in Section 2.4. In brief, gallic acid (50 lL) was added to 3 mL reactant to final concentrations of 0, 10, 20, 40, 60, 80 and 100 lg/mL. Then, the mixed solutions were subjected to Fluor-A or Fluor-B irradiation at 1.0 mW/cm2 or blue-light irradiation at 0.1 mW/cm2 for 20 min. Gallic acid can inhibit NBT reduction, and the scavenging capacity of the O 2 generated was calculated using the following equation, where A denotes the absorbance of the blue formazan measured at 560 nm.

2.3. Spectrometry of light sources and riboflavin

  O 2 scavenging activityð%Þ ¼ ðAcontrol  Asample Þ=Acontrol  100%

The emission spectra of the fluorescent lamps and LED tube lights were measured using a UV–vis miniature fibre optic spectrometer (USB4000 UV/Vis, Ocean Optics, USA) and were normalized, as shown in Fig. 1. The wavelengths of the emitted maxima of the blue, green, yellow and red lights were 463, 529, 589 and 632 nm, respectively, and the spectral widths at half height (W1/2) were 23, 31, 16 and 14 nm, respectively. The spectra of the fluorescent lamps are usually comprised of several peaks, as shown in Fig. 1.

ð1Þ 2.6. Effects of blue light on SOD activity The effects of blue light on O 2 scavenging activity were examined with the B2/NBT method using SOD, as described in Section 2.4. In brief, (A) 50 lL SOD was added to 3 mL reactant, and the final activity of SOD (1.0 unit/g) was used as a standard. Then, the mixed solutions were subjected to blue light irradiation

264

C.-w. Cheng et al. / Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267

at 0.08, 0.1 or 0.12 mW/cm2 for 10, 20 or 30 min. SOD activity was defined as one unit of SOD having a 50% inhibition on the B2/NBT system. (B) 50 lL SOD was added to 3 mL reactant, and the final activity of SOD was 0, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0, 3.0 or 4.0 unit/g. The mixed solutions were exposed to blue light irradiation at 0.12 mW/cm2 for 10, 20 or 30 min. The optimal condition for the 50% inhibition of O 2 scavenging activity with SOD (1.0 unit/g) was measured using the B2/NBT method. 2.7. Statistics Data are represented by the mean ± standard deviation of three separate experiments. A homoscedastic two-sample t-test was employed to assess whether the two sets of measurements differed, and values of P < 0.05 were considered to be significant. 3. Results 3.1. Effect of light quality on photo-decomposition of riboflavin The generation of O 2 from the intermediates during the decomposition of riboflavin in aqueous solution was detected using NBT reduction [7]. As shown in Fig. 2, the absorbance of the NBT reduction increased with the generation of O 2 by the photochemical system in the presence of riboflavin. For the photochemical treatment, the decomposition of riboflavin increased with the irradiation time. The highest efficiency photochemical reaction of riboflavin was observed under blue light irradiation. The average photochemical effects of the green, yellow and red lights relative to the blue light were approximately 4.9%. 3.9% and 2.6%, respectively. These results indicate that the effectiveness of riboflavin photolysis is mainly determined by the wavelength of light used and that the light quality is associated with the photochemical reaction of riboflavin. 3.2. Spectra of riboflavin in photoreactions Fig. 3 shows the spectra (200–800 nm) of riboflavin measured by fluorescence lamps and blue light irradiation. As observed, there were four absorption peaks, 224, 268, 373 and 445 nm, of riboflavin in the dark. The absorbance of riboflavin at 445 nm was dramatically decreased by blue light irradiation. The fluorescent

Fig. 2. Effects of colour-light irradiation at 1.0 mW/cm2 on NBT reduction for 10, 20 and 30 min. Data are represented by mean ± standard deviation, where n = 3. Significant differences (p < 0.05) between groups are indicated by different letters above the bar. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3. Absorption spectra of riboflavin irradiated by different light sources at 1.0 mW/cm2 for 20 min.

lamps had a very small impact because the variations in the spectra at 445 nm were not significant. Blue light irradiation for 20 min yielded the highest efficiency in the photo-decomposition of riboflavin. The spectra of riboflavin were measured during the course of colour illuminations in the photo-decomposition reactions [11]. Irradiation with blue light showed the highest efficiency photo-decomposition of riboflavin, while the absorbance of riboflavin at 445 nm decreasing dramatically upon illumination. The green, yellow and red lights had negligible effects because the spectral changes were not significant. Fig. 4 shows the effects of the irradiation of fluorescent lamps and blue light on the NBT reduction during the photochemical reaction of riboflavin. As observed, the photochemical reaction of riboflavin increased with the irradiation time. The

Fig. 4. Effects of fluorescent lamp irradiation at 1.0 mW/cm2 and blue light irradiation at 0.1 mW/cm2 on NBT reduction for 10, 20 and 30 min. Data are represented by mean ± standard deviation, where n = 3. Significant differences (p < 0.05) between groups are indicated by different letters over the bar. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

C.-w. Cheng et al. / Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267

photo-decomposition of riboflavin was lower under Fluor-A than under Fluor-B irradiation at 1.0 mW/cm2. 3.3. Effect of light source on

O 2

scavenging activity using gallic acid

Gallic acid is a tri-hydroxyl-benzoic acid. Phenolic compounds are considered the most important antioxidants in plants and plant-based foods [25]. Many phenolic compounds, such as gallic acid, can remove free radicals through a process similar to SOD-catalysed reactions. The free radicals serve as a substrate and are scavenged by the phenolic compounds. Fig. 5 shows the variation in O 2 scavenging activity (%) using different levels of gallic acid. As seen in Fig. 5(A), the O 2 scavenging activity increased with the addition of gallic acid and was higher under Fluor-A irradiation than under Fluor-B. A characteristic concentration of chemicals, IC50, could be determined to provide 50% inhibition activity from the correlation curve of the scavenging activity to the concentration. The IC50 of gallic acid is defined as the equivalent concentration of gallic acid that is able to remove 50% of the superoxide anion radicals. As shown in Fig. 5(B), the IC50 of gallic acid under Fluor-A and Fluor-B irradiation at 1.0 mW/cm2 was 25.7 lg/mL and 53.1 lg/mL, respectively, while the IC50 of gallic acid under blue-light irradiation at 0.1 mW/cm2 was 45.1 lg/mL. The IC50 of gallic acid under blue-light irradiation at 0.1 mW/cm2 and Fluor-B irradiation at 1.0 mW/cm2 were both insignificant.

Fig. 5. (A) O 2 scavenging activity of gallic acid under fluorescent lamp irradiation at 1.0 mW/cm2 and blue light irradiation at 0.1 mW/cm2 for 20 min. (B) The IC50 of gallic acid under fluorescent lamp irradiation at 1.0 mW/cm2 and blue light irradiation at 0.1 mW/cm2 for 20 min. Data are represented by mean ± standard deviation, where n = 3. Significant differences (p < 0.05) between groups are indicated by different letters over the bar. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

265

3.4. Effect of blue light on SOD detection The O 2 scavenging activity of one unit of SOD was determined by blue light irradiation using the B2/NBT method. As shown in Fig. 6(A), the O 2 scavenging activity of one unit of SOD decreased with an increase in the blue-light irradiation time for the photochemical treatment. The effect of the SOD activity on O 2 scavenging activity under blue-light irradiation were investigated using the B2/NBT method. As shown in Fig. 6(B), the O 2 scavenging activity increased with the SOD activity, and the 50% inhibition value of the O 2 scavenging activity at 0.12 mW/cm2 blue-light irradiation for 10, 20 and 30 min were 0.82, 0.90 and 0.97 unit SOD, respectively. The SOD activity is defined as such that one unit of SOD that has a 50% inhibition on the B2/NBT system. The 50% inhibition of the O 2 scavenging activity under 0.12 mW/cm2 blue light irradiation for 30 min was 0.97 unit SOD, which is the optimal condition for the B2/NBT method in this study.

4. Discussion As shown in Fig. 2, riboflavin exhibits the highest efficiency photochemical degradation under blue light irradiation. The effects of green, yellow and red lights on riboflavin degradation were of low efficiency, indicating the absence of any charge transfer interaction between riboflavin and the phosphate buffered solution. Ahmad et al. used a mercury vapour fluorescent lamp (emission at 405 and 435 nm) for riboflavin photolysis. A gradual decrease

Fig. 6. (A) Effect of one unit of SOD on O2 scavenging activity under 0.08, 0.1 and 0.12 mW/cm2 blue light irradiation for 10, 20 and 30 min. (B) Effect of SOD activity 2 on O 2 scavenging activity under 0.12 mW/cm blue light irradiation for 10, 20 and 30 min. Data are represented by mean ± standard deviation, where n = 3. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

266

C.-w. Cheng et al. / Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267

in the absorbance of the aqueous phase at 445 nm indicated the loss of riboflavin. On the other hand, an increase in absorbance of a chloroform extract at 356 and 445 nm exhibited the formation of lumichrome and lumiflavin, respectively, with time [26]. The effectiveness of the riboflavin photolysis is mainly determined by the wavelength of light. The photochemical degradation of riboflavin may proceed through the photoreduction of the isoalloxazine ring by electrons donated by the ribityl side chain [9]. As shown in Fig. 3, the ratio between the absorptions at 445 nm and 373 nm indicates the efficiency of the photo-decomposition of riboflavin. The effectiveness values of dark, Fluor-A, Fluor-B and blue light irradiation at 1.0 mW/cm2 for 20 min were 1.65, 1.12, 1.07 and 0.79, respectively. The lower the effectiveness value, the higher the yield of the riboflavin photo-decomposition was. Blue light was found to be the most efficient for the photo-decomposition of riboflavin, and the spectra of riboflavin were changed as a result of photo-degradation. Human eyes are very sensitive to visible light at the wavelength of 555 nm [27]. The colours detected by human eyes depend on the specific wavelengths of the light sources. As shown in Table 1, Fluor-A and Fluor-B have same radiance intensity, but the illumination intensity of Fluor-A is higher than that of Fluor-B. At the same luminance, the IC50 of gallic acid under Fluor-A irradiation at 4000 lux (0.84 mW/cm2) treatment was 32.1 lg/mL, while that under Fluor-B irradiation at 4000 lux (1.0 mW/cm2) was 53.1 lg/mL. As shown in Fig. 5(B), the IC50 of gallic acid is 2.1-fold higher under Fluor-B than under Fluor-A irradiation at the same radiance intensity (1.0 mW/cm2). The scavenging capacity of O 2 by gallic acid is called SOD-like activity, and it can inhibit the riboflavin-mediated reduction of NBT. The IC50 of gallic acid is inversely proportional to the SOD-like activity. Hence, the SOD-like activity of gallic acid is 2.1-fold higher under Fluor-A than under Fluor-B irradiation at the same radiance intensity (1.0 mW/cm2). As seen in Fig. 4, the photochemical reaction of riboflavin was lower under Fluor-A than under Fluor-B irradiation at the same radiance intensity. The more O 2 were generated from the excited riboflavin, the more antioxidants were required for the elimination of O 2 in the B2/NBT method. The spectra of the fluorescent lamps comprised multiple colour lights, as shown in Fig. 1. The emission spectra of fluorescent lamps made by different manufacturers may vary. Different fluorescent lamps might also generate different amounts of O 2 from the photo-decomposition of riboflavin at the same irradiance or luminance. To ensure high accuracy, the widely accepted B2/NBT assay for the quantification of SOD activity by fluorescent lamps has to be validated. As shown in Figs. 4 and 5(B), the photochemical reaction of riboflavin and the IC50 of gallic acid under Fluor-A irradiation at 1.0 mW/cm2 were similar to those under blue LED irradiation at 0.1 mW/cm2, as determined by the B2/NBT method in this study. After being light photo-energized, riboflavin is converted into excited triplet-state riboflavin. Superoxide anion or singlet oxygen is produced through the reaction of the excited triplet-state riboflavin with triplet oxygen [8,9]. However, the quality of blue light in the emission of the fluorescent lamps plays a major role in the

Table 1 The measurements of luminance and irradiance of fluorescence lamps and LED tube lights. Light source

Luminance (lux)

Fluor-A Fluor-B Blue LED Green LED Red LED Irradiance (mW/cm2)

2070 1980 350 4560 750 0.5

4780 4000 670 10,190 1220 1.0

5940 5340 910 12,790 1830 1.5

8240 7160 1290 19,110 2460 2.0

photo-decomposition of riboflavin. The effectiveness of the riboflavin photolysis is controlled by the wavelength of the light source. The photo-decomposition of riboflavin under blue light at a low radiance intensity was selected to optimize the B2/NBT method. The emission spectra of coloured LEDs were always pure, clear and in a narrow wavelength range. The blue LED light showed the highest efficiency in the B2/NBT method. For the same energy dose (0.144 J/cm2), the effects of one unit of SOD on the O 2 scavenging activity after blue-light illumination for 30 min at 0.08 mW/cm2 and for 20 min at 0.12 mW/cm2 were 64.5% and 55.6%, respectively, as shown in Fig. 6(A). These results show that the light intensity (irradiance) has greater influence on the photo-decomposition of riboflavin than the irradiation time. 5. Conclusions The effectiveness of photolysis is controlled by the wavelength of the light source. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. In this study, blue light was found to exhibit the highest efficiency photochemical reaction of riboflavin. It is concluded that the blue LED light is better than the fluorescent lamp for the photo-decomposition of riboflavin. Irradiation by blue light at 0.12 mW/cm2 for 30 min is determined to be the optimal condition for the B2/NBT method. Acknowledgment The financial support in this work is partially from the Ministry of Science and Technology, Taiwan, under Contracts No. MOST 103-2113-M-130-001 (Grant to L.-Y. Chen). References [1] L.-S. Lai, P.-C. Chang, C.-T. Chang, Isolation and characterization of superoxide dismutase from wheat seedlings, J. Agric. Food Chem. 56 (2008) 8121–8129. [2] L.Y. Chen, C.W. Cheng, J.Y. Liang, Effect of esterification condensation on the Folin–Ciocalteu method for the quantitative measurement of total phenols, Food Chem. 170 (2015) 10–15. [3] R. Zimmermann, L. Flohe, U. Weser, H.J. Hartmann, Inhibition of lipid peroxidation in isolated inner membrane of rat liver mitochondria by superoxide dismutase, FEBS Lett. 29 (1973) 117–120. [4] B. Halliwell, J.M. Gutteridge, Role of free radicals and catalytic metal ions in human disease: an overview, Methods Enzymol. 186 (1990) 1–85. [5] J.W. Juen, H.L. Jian, J.Y. Liang, The effect of illuminance on light induced reduction of nitro blue tetrazolium, MC-Trans. Biotechnol. (2010). [6] J.K. Donnelly, K.M. McLellan, J.L. Walker, D.S. Robinson, Superoxide dismutases in foods. A review, Food Chem. 33 (1989) 243–270. [7] W.F. Beyer Jr., I. Fridovich, Assaying for superoxide dismutase activity: some large consequences of minor changes in conditions, Anal. Biochem. 161 (1987) 559–566. [8] P.B. Ottaway, Stability of vitamins in food, in: The Technology of Vitamins in Food, Chapman and Hall, London, 1993, pp. 233–244. [9] Y. Lin, R.R. Eitenmiller, W.O. Landen, Riboflavin, in: Vitamin Analysis for the Health and Food Sciences, CRC Press, 2008, pp. 329–360. [10] J.-Y. Liang, C.-W. Cheng, C.-H. Yu, L.-Y. Chen, Investigations of blue lightinduced reactive oxygen species from flavin mononucleotide on inactivation of E. coli, J. Photochem. Photobiol., B 143 (2015) 82–88. [11] J.-Y. Liang, J.-M.P. Yuann, C.-W. Cheng, H.-L. Jian, C.-C. Lin, L.-Y. Chen, Blue light induced free radicals from riboflavin on E. coli DNA damage, J. Photochem. Photobiol., B 119 (2013) 60–64. [12] C. Beauchamp, I. Fridovich, Superoxide dismutase: improved assays and an assay applicable to acrylamide gels, Anal. Biochem. 44 (1971) 276–287. [13] M. Behnamnia, K.M. Kalantar, J. Ziaie, The effects of brassinosteroid on the induction of biochemical changes in Lycopersicon esculentum under drought stress, Turk. J. Bot. 33 (2009) 417–428. [14] H.-S. Kim, C.-D. Jin, Polyamines as antioxidant protectors against paraquat damage in radish (Raphanus sativus L.) cotyledons, J. Plant Biol. 49 (2006) 237–246. [15] A. Boonmee, C. Srisomsap, A. Karnchanatat, P. Sangvanich, An antioxidant protein in Curcuma comosa Roxb. Rhizomes, Food Chem. 124 (2011) 476–480. [16] S. Sundaram, S. Anjum, P. Dwivedi, G. Rai, Antioxidant activity and protective effect of banana peel against oxidative hemolysis of human erythrocyte at different stages of ripening, Appl. Biochem. Biotechnol. 164 (2011) 1192–1206.

C.-w. Cheng et al. / Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267 [17] M. Dog˘an, Investigation of the effect of salt stress on the antioxidant enzyme activities on the young and old leaves of salsola (Stenoptera) and tomato (Lycopersicon esculentum L.), Afr. J. Plant Sci. 6 (2012) 62–72. [18] C. Wang, X. Luo, Y. Tian, Y. Xie, S. Wang, Y. Li, L. Tian, X. Wang, Biphasic effects of lanthanum on Vicia faba L. seedlings under cadmium stress, implicating finite antioxidation and potential ecological risk, Chemosphere 86 (2012) 530– 537. [19] H. Chen, M. Zhang, B. Xie, Components and antioxidant activity of polysaccharide conjugate from green tea, Food Chem. 90 (2005) 17–21. [20] S. Gangwar, V. Singh, S. Prasad, J. Maurya, Differential responses of pea seedlings to indole acetic acid under manganese toxicity, Acta Physiol. Plant 33 (2011) 451–462. [21] S. Verma, S.N. Mishra, Putrescine alleviation of growth in salt stressed Brassica juncea by inducing antioxidative defense system, J. Plant Physiol. 162 (2005) 669–677.

267

[22] H.-L. Jian, C.-W. Cheng, L.-Y. Chen, J.-Y. Liang, The photochemistry of riboflavin, MC-Trans. Biotechnol. 3 (2011) 1–11. [23] J.M. McCord, I. Fridovich, Superoxide dismutase. An enzymic function for erythrocuprein (hemocuprein), J. Biol. Chem. 244 (1969) 6049–6055. [24] C. Beauchamp, I. Fridovich, Superoxide dismutase: improved assays and an assay applicable to acrylamide gels, Anal. Biochem. 44 (1971) 276–287. [25] A. Mariod, B. Matthäus, Y.A. Idris, S. Abdelwahab, Fatty acids, tocopherols, phenolics and the antimicrobial effect of sclerocarya birrea kernels with different harvesting dates, J. Am. Oil Chem. Soc. 87 (2010) 377–384. [26] I. Ahmad, S. Ahmed, M.A. Sheraz, F.H. Vaid, Effect of borate buffer on the photolysis of riboflavin in aqueous solution, Journal of photochemistry and photobiology. B, Biology 93 (2008) 82–87. [27] D. Boucar, P. Ramchandra, Light Emitting Diodes, Solar Lighting, 2011.

Loading...

Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity.

Journal of Photochemistry and Photobiology B: Biology 148 (2015) 262–267 Contents lists available at ScienceDirect Journal of Photochemistry and Pho...

982KB Sizes 15 Downloads 285 Views

Recommend Documents

Determination of superoxide dismutase mimetic activity in common culinary herbs.
Under conditions of oxidative stress, the removal of superoxide, a free radical associated with chronic inflammation, is catalysed by superoxide dismutase (SOD). Thus in addition to acting as an antioxidant, SOD may also be utilized as an anti-inflam

catalase mimetics on human breast cancer cells.
Reactive oxygen species (ROS) such as superoxide and hydrogen peroxide (H2O2) have been implicated in development and progression of breast cancer. In the present study, we have evaluated the effects of the superoxide dismutase (SOD) mimetic MnTmPyP

Species-specific antifungal activity of blue light.
Fungal pathogens represent a significant threat to immunocompromised patients or individuals with traumatic injury. Strategies to efficiently remove fungal spores from hospital surfaces and, ideally, patient skin thus offer the prospect of dramatical

Lamellar superoxide dismutase of isolated chloroplasts.
Photooxidation of hydroxylamine to nitrite by spinach (Spinacia oleracea L. and sugarbeet (Beta vulgaris L.) chloroplast lamellae in the presence of autoxidable electron acceptors is inhibited by either solubilized or membrane-bound superoxide dismut

LSU network hubs integrate abiotic and biotic stress responses via interaction with the superoxide dismutase FSD2.
In natural environments, plants often experience different stresses simultaneously, and adverse abiotic conditions can weaken the plant immune system. Interactome mapping revealed that the LOW SULPHUR UPREGULATED (LSU) proteins are hubs in an Arabido

Acute ketamine impairs mitochondrial function and promotes superoxide dismutase activity in the rat brain.
Ketamine is often associated with altered mitochondrial function and oxidative stress. Nevertheless, limited data are still available regarding the in vivo action of ketamine in mitochondrial bioenergetics and redox state. Accumulating evidence suppo

Assessment of antioxidants status and superoxide dismutase activity in HIV-infected children.
This study aims to assess the nutritional status of selenium, copper and zinc; and also the erythrocyte superoxide dismutase activity of HIV-infected children compared to a control group.

Communities in the iron superoxide dismutase amino acid network.
Amino acid networks (AANs) analysis is a new way to reveal the relationship between protein structure and function. We constructed six different types of AANs based on iron superoxide dismutase (Fe-SOD) three-dimensional structure information. These

Meta-Analyses of Manganese Superoxide Dismutase Activity, Gene Ala-9Val Polymorphism, and the Risk of Schizophrenia.
Schizophrenia is a complex and disabling psychiatric disorder, and tardive dyskinesia (TD) is a severe adverse drug effect occurring in 20% to 40% of schizophrenic patients chronically treated with typical neuroleptics. Previous studies suggested tha