Uv 2401 pc spectrophotometer

Ground dry plant materials (0.5 g) were weighed into a test tube and mixed with 7 mL of 80% aqueous methanol (acidifies with 1% HCl) and the suspension was stirred slightly. Tubes were sonicated twice in Sonic 6D water bath (Polsonic; Warsaw, Poland) for 15 min and extract was centrifuged (5 min, 1000 g).
The ferric reducing ability of plasma (FRAP) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) antioxidant assays were determined following Benzie and Strain [41 (link)] and Re et al. [42 (link)], respectively, using a Shimadzu UV-2401 PC spectrophotometer (Kyoto, Japan). The Oxygen Radical Absorbance Capacity (ORAC) assay was determined on Shimadzu RF-5301 PC spectrofluorometer (Kyoto, Japan) following the method previously described by Ou et al. [43 (link)]. All determinations were performed in triplicate. The results were expressed in mM Trolox per 100 g of DM.
The α-amylase and α-glucosidase inhibitory effects of the artichoke leaf extracts were assayed according to the procedure described previously by Wojdyło et al. [20 (link)] with slight modifications. The inhibition of AChE and BuChE activity was determined based on Ellman’s method, as reported previously by Wojdyło et al. [40 (link)]. All samples were assayed in triplicate and the result was expressed as IC₅₀. Analysis was performed using the UV-2401 PC spectrophotometer (Shimadzu; Kyoto, Japan).

UV–vis absorption spectra were recorded on a Shimadzu UV-2401 PC spectrophotometer in CHCl₃/CH₃CN (9/1 v/v). Titrations of TAB were carried out with CH₃Cl/CH₃CN solutions (c = 6.0 µmol L^–1, 9/1 v/v, 2 mL) and addition of aliquots (25 µL) of a solution containing a mixture of Zn(NTf₂)₂ (c = 126 µmol L^–1) and TAB (c = 6.0 µmol L^–1) in CH₃Cl/CH₃CN (9/1 v/v, 10 mL). Titrations of BKB were carried out with CH₃Cl/CH₃CN solutions (c = 9.4 μmol L^–1, 9/1 v/v, 2 mL) and addition of aliquots (25 µL) of a solution containing a mixture of Zn(NTf₂)₂ (c = 129 µmol L^–1) and BKB (c = 9.4 µmol L^–1) in CH₃Cl/CH₃CN (9/1 v/v, 10 mL). UV–vis spectra were recorded after the addition of each aliquot. To determine the stoichiometry for the metal–ligand complex formation, the absorption intensity at 340 nm of the metal–ligand charge transfer band was plotted against the metal-to-ligand ratio. UV–vis spectra of solid films of TAB and TAB:Zn with different amounts of the Zn(NTf₂)₂ metal salt were recorded in transmission on a Shimadzu UV-2401 PC spectrophotometer. Thin films (thickness <10 µm) were prepared by spin-coating (Spincoater Model P6700, Specialty Coating Systems, Inc.) ca. 5 µL of solutions of TAB (25 mg mL^–1) in CHCl₃/CH₃CN (9/1 v/v) or TAB:Zn (25 mg mL^–1) in CHCl₃/CH₃CN (9/1 v/v) with 0.5, 1.0, or 1.5 molar equivalents of Zn(NTf₂)₂ on quartz glass slides.

The extraction for the antioxidant capacity was conducted following a protocol described by Lachowicz et al. [37 (link)]. The total polyphenolic content of the sourdough samples was determined using the Folin–Ciocalteu spectrophotometric method [38 (link)]. The absorbance at 765 nm was measured after 1 h, using the UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan). The results were expressed as mg of gallic acid equivalents (GAE) per 100 g of dry sourdough. Data were expressed as the mean value for three measurements. The ABTS and FRAP methods were carried out with the methods described by Re et al. [39 (link)] and Benzie and Strain [40 (link)]. The absorbance was measured at 734 nm and 593 nm using the UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan). The results of antiradical capacity were expressed as Trolox equivalents in mmol per 100 g of dry sample. Data were expressed as the mean value for three measurements.

Rye bread (1 g) was mixed with 80% of methanol and water (10 mL) + 1% hydrochloric acid, and incubated for 20 min under sonication (Sonic 6D, Polsonic, Warsaw, Poland). Next, the slurry was centrifuged at 19,000× g for 10 min, and the supernatant was filtered through a hydrophilic PTFE 0.20 μm membrane (Merck, Darmstadt, Germany) and used for analysis.
The ABTS method was performed according to the method described by Re et al. [22 (link)]. ABTS^•+ was generated by oxidation of ABTS with potassiumpersulphate. The ABTS^•+ solution was diluted to an absorbance of 0.7 ± 0.05 at 734 nm. Then, 0.03 mL of extract was mixed with 2.97 mL of ABTS^•+ solution and left for 6 min at 25 °C. Next, the absorbance was measured at 734 nm using the UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan). The results of antiradical capacity were expressed as Trolox equivalents in µmol per g d.s.
The DPPH method was carried out with the method described by Yen and Chen [23 (link)]. Then, 0.50 mL of extract was mixed with ethanol (1.5 mL) and DPPH^•+ solution (0.5 mL), and left for 10 min at 25 °C. Next, the absorbance was measured at 517 nm using the UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan). The results of antiradical activity were expressed as Trolox equivalents in µmol per g d.s.

The total content of carotenoids as well as that of a and b chlorophyll was determined by the colorimetric method (UV-160A spectrophotometer, Shimadzu, Osaka, Japan). 15 mL of 100% acetone was added to a 2 g kale sample and then left for 24 h at 4 °C. The sample then underwent centrifugation at 12500 rpm for 5 min. Absorbance coefficients were measured at wavelengths of 661.6, 644.8 and 470 nm. The contents of carotenoids and chlorophyll a and b in kale were calculated [51 (link)].
Polyphenols were tested using the Folin-Ciocalteu method (Shimadzu UV-2401 PC spectrophotometer, Osaka, Japan), in which gallic acid was utilised. The sample absorbance was measured at a wavelength of 765 nm, and the result was expressed in terms of gallic acid (mg gallic acid /100 g dry matter) [52 (link)].
The kale’s antioxidant capacity were tested using the ABTS⁺ method (Shimadzu UV-2401 PC spectrophotometer, Osaka, Japan). ABTS⁺ solution was diluted with redistilled water until it reached 0.700 (±0.002) absorbance at a wavelength of 743 nm. 60 µL of supernatant solution was then added to 3 mL of ABTS⁺, and the absorbance measurement was conducted after 6 min [53 (link)].
All tests were repeated three times, with the exception of the colour parameters, which were repeated six times.

For the antioxidant activity determination, the samples were prepared according to the method described by Lachowicz et al. (2021) [17 (link)]. The total polyphenol content of the samples was determined using the Folin–Ciocalteu spectrophotometric method [18 (link)] with absorbance measured at 765 nm after 1 h using a UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan). Results are expressed as mg gallic acid equivalents (GAE) per 100 g dry sourdough. Data are expressed as the mean of three measurements. The anti-radical activity measured using ABTS^•+assay and the FRAP assay, which measures the antioxidant activity of compounds capable of reducing the ferric complex, were conducted following the protocols outlined by Re et al. (1999) [19 (link)] and Benzie and Strain (1996) [20 (link)]. Absorbance was measured at 734 nm and 593 nm using a UV-2401 PC spectrophotometer (Shimadzu, Kyoto, Japan). The results are expressed as Trolox equivalents in mmol/L per 100 g dry sample. Data are expressed as the mean of three measurements.

Inhibition of cholinesterase was assessed using the acetylcholinesterase (AChE) and butylcholinesterase (BuChE) methods described before by Wojdyło et al. [17 (link)]. The reaction mixture consisted of a sample of P. domestica extract, Tris-HCl buffer (pH 8.0), acetylthiocholine iodide or S-butylthiocholine iodide and 5,5′-dithiobis(2-nitrobenzoic acid). After incubation at 37 °C for 10 min, AChE or BuChE solution was added. The absorbance was measured after 15 min at 412 nm. The results were expressed as IC₅₀ (mg/mL). All assays were performed in triplicate with a PC UV-2401 spectrophotometer (Shimadzu, Kyoto, Japan).