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SUPPLEMENTARY MATERIALS
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Figure S1 can be found at DOI: xxx-xxxx.s1.
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Figure S2 can be found at DOI: xxx-xxxx.s2.
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Table S1 can be found at DOI: xxx-xxxx.ts1.
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Table S2 can be found at DOI: xxx-xxxx.ts2.
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Table S1. Total Irradiance of Light Source (250-900 nm) and the UV Component
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(250-400 nm) and % of total measured in all three light intensities (1,000, 2,000 and
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4,000 Lux) under all conditions (light, light with UV filter, light with borosilicate tube
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and no light).
Light
Intensity
(lux)
4000
4000
4000
2000
2000
2000
Condition
light
source
light
source with
UV cut off
filter
light
source with
borosilicate
tube
light
source
light
source with
UV cut off
filter
light
source with
borosilicate
tube
Irradiance
Irradiance
250 – 900
250 – 400
2
nm (μW/cm ) nm (μW/cm2)
% of total
light source
output
8841.9067
9.4836
0.1073 %
% of UV
portion of
light
source
output
100 %
7780.8779
1.1380
0.0129 %
12.000 %
8016.6621
8.5984
0.0972 %
90.6667 %
7780.8779
3.7783
0.0486 %
100 %
6994.9306
0.3817
0.0049 %
10.1010 %
7309.309545
3.5494
0.0456 %
93.9394 %
IRBP protects retinol from photodegradation
1000
1000
1000
0
light
source
light
source with
UV cut off
filter
light
source with
borosilicate
tube
no light
source
5894.604472
1.4517
0.0246 %
100 %
5501.630841
0.0968
0.0016 %
6.6667 %
5501.630841
1.3550
0.0230 %
93.3333 %
0.0747
0.0012
0.0008 %
0.0127 %
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Table S2. Recorded Temperature (at the test samples inside the test tube; with and
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without light source at 4,000 Lux or 8,842 W/cm2) at time 0, 10, 20, 30 min of
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experiment.
Time (min)
15
16
Sample
0
10
20
30
60
1 (4000 Lux)
22
22
22
22
22
2 (4000 Lux)
22
22
22
22
22
3 (4000 Lux)
22
22
22
22
22
4 (dark)
22
22
22
22
22
5 (dark)
22
22
22
22
22
6 (dark)
22
22
22
22
22
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Figure S1. UV Emission Spectra of Light Source (A) and Transmission Profile of
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FGL400 UV filter (B). Total irradiance of light source is 8,842 W/cm2 from 250-900
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nm (light intensity: 4,000Lux). Emission spectra for the light source were first obtained
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with a PTI QuantaMaster 500 spectrophotometer. Fig.S1A shows spectra taken under
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conditions with the light bulb (blue line; 4,000 Lux or 8,842 μW/cm 2, 250-400 nm), with the
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light bulb and an UV short pass filter (red ), and with the light bulb and borosilicate test
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IRBP protects retinol from photodegradation
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tubes (green), and with the light bulb turned off for a background spectrum (black ).
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Based on the manufacturer’s specification, the UV shortpass filter transmits minimal light
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with a wavelength shorter than 400 nm but transmits nearly 90% in the visible and IR
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(Thorlabs FGL400, see transmittance profile in Fig. S1B). A borosilicate glass tube (used
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for holding the samples in experiments in the present study) was used to evaluate how
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much of the emitted light was absorbed by the borosilicate test tube. In both cases, the
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UV filter or the test tube was placed directly in front of the entrance slit to the
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monochromator at the same distance from the light source as the original samples. To
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derive power densities, spectra were first background corrected (black line). Total power
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density was measured using a SpectraPhysics power meter to obtain power in Watts and
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dividing by the sensor area. Power densities were measured under the same conditions
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(all four lines in Fig. S1). By integrating under the entire curve for condition (red line) and
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correlating that to 100% of the power density, the corresponding power densities for
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spectral regions can be obtained by a simple ratio of the area of interest (250 – 400 nm)
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to the total area (250 – 900). In this way, the power densities for UV range (250-400 nm)
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were calculated using the data for all conditions. This experiment was repeated for all
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four light intensities used for our retinol degradation study. All power densities and %
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light source are reported in Table S1.
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Figure S2. Reversal of Retinol Photodegradation by UV Filter and UV/VIS Filter.
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Percent change in retinol concentration at time 0 and 30 min by indicated
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treatments are presented in (A). Transmission profile of UV-VIS filter FEL1000 is
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shown in (B) [Note: See Fig. S1 B for transmission profile of UV filter ]. To examine
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the effect of UV light on retinol degradation,2, experiments were performed using a short
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IRBP protects retinol from photodegradation
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pass UV filter (to minimize UV light; see Fig. S1 B for transmittance profile of FGL400
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from Thorlabs) and a long pass UV/VIS filter (to minimize UV/VIS light; see Fig. S2 B for
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transmittance profile of FEL1000 from Thorlabs). To accommodate these light filters, a
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sample chamber was connected to the light chambers by a short circular cylinder (with a
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2 inch diameter).
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Retinol samples were exposed to light intensity of 4,000 Lux (or 8,842 μW/cm 2; measured
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at the sample) for 30 min with and without filter. Changes in retinol level were measured
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by a spectrophotometer (at 325 nm) and also by HPLC. Fig. S2 shows that light
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exposure for 30 min significantly reduced retinol concentration (from 100% to 25%). The
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removal of UV light (by the FGL400 filter) resulted in an almost complete reversal of this
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degradation (i.e. returned to 81% from 25%) suggesting that the UV component of the
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light source was mainly responsible for retinol degradation. Furthermore, the exclusion of
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both UV and VIS source (by a UV/VIS filter FEL1000) did not significantly change this
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level of reversal of retinol degradation, suggesting that light from the VIS range did not
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contribute a significant role in retinol degradation (n=3, mean and standard errors are
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show in the figure).
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65
66
67
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IRBP protects retinol from photodegradation
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Figure S1
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70
71
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IRBP protects retinol from photodegradation
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Figure S2
120
100
% ATOL
80
60
40
20
0
TO DARK
73
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T30 DARK
T30 LIGHT at
4,000 lux
A
B
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T30 LIGHT at
4,000 lux + UV
Filter
T30 LIGHT at
4,000 lux +
UV/VIS Filter