Figure 1.
Ultraviolet-visible spectra of proanthocyanidin.
Figure 2.
Bactericidal effect of photo-irradiated proanthocyanidin in relation to the concentration.
For the L(+) condition, the laser irradiation was performed at an output power of 300 mW for 10 min. Each value is the mean of four independent measurements with the standard deviation. Significant differences from the initial bacterial count are shown as p<0.01 (**).
Figure 3.
The influence of laser irradiation time and laser output power on the bactericidal effect of photo-irradiated proanthocyanidin.
(A) Time-course changes in CFU/mL under the conditions of P(+)L(+), P(−)L(+)and P(+)L(−). For the P(+) condition, 1 mg/mL proanthocyanidin was used. For the L(+) condition, laser output power was set at 300 mW. (B) Bactericidal activity of 1 mg/mL proanthocyanidin irradiated with the laser-light at different output powers. Each value is the mean of three independent measurements with the standard deviation. Significant differences between the conditions are demonstrated by the same alphabetic letters. p<0.05 (a), p<0.01 (b, c, d, e).
Table 1.
ANOVA summary table for the time-course changes in the CFU/mL in each treatment group.
Figure 4.
ESR-spin trapping analysis for hydroxyl radicals and superoxide anion radicals generated in photo-irradiated proanthocyanidin aqueous solution.
(A) Representative ESR signals of DMPO-OH (open circle) and DMPO-OOH (solid circle) obtained when proanthocyanidin aqueous solution was irradiated with the laser-light for 15 s. (B) The yields of DMPO-OH and DMPO-OOH after given concentrations of proanthocyanidin were irradiated with the laser-light for 15 s. Each value is the mean of three independent measurements with the standard deviation.
Figure 5.
The influence of laser irradiation time on the yields of DMPO-OH and DMPO-OOH.
(A) Time-course changes in the yields of DMPO-OH and DMPO-OOH when 1 mg/mL proanthocyanidin was irradiated at an output power of 300 mW. (B) The comparison of the yields of DMPO-OH and DMPO-OOH generated in the photo-irradiated proanthocyanidin with or without the prior laser irradiation. There were no statistically significant differences between the two groups. Each value is the mean of three independent measurements with the standard deviation.
Figure 6.
The influence of laser output power on the yields of DMPO-OH and DMPO-OOH.
Proanthocyanidin (1 mg/mL) was irradiated with the laser-light for 15 s. Each value is the mean of three independent measurements with the standard deviation. Significant differences between the conditions are shown as p<0.05 (*) and p<0.01 (**).
Figure 7.
The yield of DMPO-OH and DMPO-OOH generated by photo-irradiation of 1 mg/mL proanthocyanidin with or without argon gas replacement.
The laser irradiation was performed at an output power of 300 mW for 30 s. Each value is the mean of three independent measurements with the standard deviation. Significant differences between the conditions are shown as p<0.01 (**).
Figure 8.
Quantification of H2O2 generated in photo-irradiated proanthocyanidin aqueous solution.
(A) Standard curve for the analysis. (B) The yield of H2O2 in the 1 mg/mL proanthocyanidin aqueous solution when irradiated with the laser at an output power of 300 mW. Each value is the mean of three independent measurements with the standard deviation.
Figure 9.
The yield of DMPO-OH and DMPO-OOH generated by photo-irradiation of 1 mg/mL proanthocyanidin at different wavelengths.
Photo-irradiation at each wavelength was performed at irradiance of 30 mW/cm2 for 120 s. Each value is the mean of three independent measurements with the standard deviation. Significant differences between the conditions are demonstrated by the same alphabetic letters. p<0.01 (a, b). ND: not detected.
Figure 10.
Absorbance of 1 mg/mL proanthocyanidin at each wavelength.
Each value is the mean of three independent measurements with the standard deviation. Significant differences in the absorbance at given wavelengths are shown as p<0.01 (**).