V 550 spectrophotometer

Chlorophyll-a fluorescence of intact leaves was measured at 22°C using a Dual-PAM-100 instrument (Heinz Walz GmbH, Effeltrich, Germany). The maximum quantum efficiency of PSII photochemistry (F_V/F_M) and light-response curves of linear electron transport (ETRII) were measured on intact leaves after at least 30 min of dark adaptation. To calculate linear electron transport rates (ETRII), for each actinic light intensity, the PSII operating efficiency was multiplied with the corresponding photosynthetically active photon flux density, assuming an equal distribution of excitation energy between the two photosystems. The linear electron transport rates were corrected for the leaf absorbance measured with an integrating sphere (ISV-469, Jasco) attached to the Jasco V-550 spectrophotometer. Transmittance and reflectance spectra of leaves were recorded between 400 and 700 nm wavelength, and leaf absorbance was calculated as 100% minus transmittance of light through the leaf minus reflectance on the leaf surface. The average value of the absorbance spectrum between 400 and 700 nm was used for the calculation of linear electron flux, assuming an equal distribution of absorbed light between both photosystems.

TLC was performed on a plate coated with Wakogel B-5F (manufactured by Fujifilm Wako Pure Chemical, Japan) followed by drying. The UV-vis absorption spectrum of each sample was recorded using a JASCO V-550 spectrophotometer, and the NMR spectrum of each sample was recorded using a Delta ECA-500 NMR spectrometer (JASCO Corporation, Japan). Resistance to light was investigated using a SUNTEST CPS + instrument (manufactured by Taiyo Seiki Co., Ltd., 550 W/cm², 300–800 nm, Japan). High-performance liquid chromatography (HPLC) was performed using an SPD-20A UV-Vis detector, a CTO-20A column oven, DGU-20A degasser, and an LC-20AD pump (all manufactured by Shimadzu Corporation, Japan).
Peaks consistent with anthracene were observed near 385 and 405 nm for 1. In this study, a 385 nm LED light (122 mW/cm², L-STND, manufactured by OptoCode, Japan) and a 405 nm LED light (133 mW/cm², L-STND, manufactured by OptoCode, Japan) were used as light sources. EY has an absorption band centered at 530 nm. A 530 nm LED light (42 mW/cm², L-STND, manufactured by OptoCode, Japan) was used for the reactions involving EY.

To evaluate the effect of PEEs on enzymatic activities, Caco-2 cell line was seeded at 1 × 10⁶ cells/100 mm dish and treated for 48 h with PEE at 100 μg/mL. Cells were rinsed with ice-cold PBS and lysed in 50 mM Tris–HCl pH 7.4, 150 mM NaCl, 5 mM EDTA, 10% glycerol, and 1% NP-40, containing protease inhibitors (1 μM leupeptin, 2 μg/mL aprotinin, 1 μg/mL pepstatin and 1 mM PMSF). Homogenates were obtained by passing five times through a blunt 20-gauge needle fitted to a syringe and then centrifuged at 15,000 × g for 30 min at 4°C. Supernatants were used to measure the enzymatic activities: Glutathione S-transferase (GST) was assayed as previously described by the method in the study by (31 (link)); glutathione reductase (GR) was assayed according to the method described in the study by (32 (link)); glutathione peroxidase (GPox) was assayed as reported in the study by (33 (link)); superoxide dismutase (SOD) was assayed as previously described in the study by (34 (link)); catalase (CAT) was assayed according to the method described in (35 (link)). All the experiments were normalized against an untreated control (CTRL). Enzymatic activities were expressed in international units and referred to protein concentration as determined by the Bradford method. All assays were performed in triplicate at 25°C in a Jasco V-550 Spectrophotometer.

UV LED (λ_exc = 365 nm, M365LP1, Thorlabs, Newton, New Jersey, USA) was used to perform photochromic reaction in a 1 cm × 1 cm fused silica cuvette placed in a temperature-controlled cuvette holder (Flash 300, Quantum Northwest, Liberty Lake, Washington, USA) with stirring (see Scheme S1). The volume of the solution was about 1.5 mL. Changes in UV-vis absorption spectra over seconds were recorded by a FLAME-T-VIS-NIR-ES USB spectrometer (6 s⁻¹ sampling rate, Ocean Optics, Largo, Florida, USA). White-light of 150 W xenon lamp (Applied Photophysics, Leatherhead, Surrey, United Kingdom) with intensity reduced to a small level was used as a probing beam. 150 ms were used for accumulation of each white-light continuum spectrum. An average of 60 initial spectra before sample UV-irradiation was used to calculate ${\mathrm{I}}_0\left(\mathsf{\lambda }\right)$ spectrum, the next spectra $\mathrm{I}\left(\mathsf{\lambda }\right)$ at subsequent times were measured upon or after UV-irradiation to determine the transient absorption spectra accordingly to formula: $\Delta \mathrm{A}\left(\mathsf{\lambda }\right)=\log \frac{{\mathrm{I}}_0\left(\mathsf{\lambda }\right)}{\mathrm{I}\left(\mathsf{\lambda }\right)}$ .
In order to study influence of UV irradiation power on TT formation a V-550 spectrophotometer (Jasco, Hachioji-shi, Tokyo) equipped with the mentioned above temperature-controlled cuvette holder, stirring and UV LED source was used.

Absorption spectra were recorded on Jasco v-550 spectrophotometer (Japan) in the range of 400–620 nm to detect the Hb states (oxyHb, deoxyHb, and metHb). Quartz cuvettes of path length 1cm were used and the scan rate was 100 nm/min. We estimated the efficiency of metHb reduction with sodium dithionite (Na₂S₂O₄) using the algorithm first proposed by [13 (link)]. The method uses the first derivative of the spectrum at 645 nm and allows the determination of the metHb saturation percentage and the total hemoglobin concentration in the sample.