The stable dark-violet 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical has a maximum absorption at 517 nm, which is reduced in the presence of antioxidants. A DPPH stock solution (0.5 mM) was prepared in ethanol. The stock solution was diluted to approximately 60 μM and showed an initial absorbance of 0.62 ± 0.02 at 517 nm at room temperature. Each essential oil sample from the seasonal study (50 μL, 10 mg/mL) was mixed with Tween 20 solution (0.5%, 50 μL, w/w) and then added to the DPPH (0.5 mM, 1900 μL) in ethanol. For each sample, an ethanol control blank was also measured. The absorbance was measured (Ultrospec™ 7000, Biochrom US, Holliston, MA, USA) at the start of the reaction (time zero), every 5 min during the first 30 min, and then at 30 min intervals until constant absorbance values were observed (plateau of reaction, 2 h). A Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) (Sigma-Aldrich, St. Louis, MO, USA) standard curve was prepared using concentrations of 30, 60, 150, 200, and 250 μg/mL. The DPPH free-radical inhibitions were expressed as milligrams of Trolox (mg TE/g) equivalents per gram of the sample [37 (link),38 (link)].
Ultrospec 7000
Manufactured by Harvard Bioscience
Sourced in United States, United Kingdom
The Ultrospec 7000 is a high-performance UV/Visible spectrophotometer designed for accurate and reliable measurements in a wide range of applications. It features a robust design, advanced optics, and intuitive software to provide precise and reproducible results.
Automatically generated - may contain errors
Lab products found in correlation
6 hydroxy 2 5 7 8 tetramethylchroman 2 carboxylic acid trolox, by Merck Group (1 mentions)
Trolox, by Merck Group (1 mentions)
Zetasizer nano z, by Malvern Panalytical (1 mentions)
Muse cell analyzer, by Merck Group (1 mentions)
Fei talos f200, by Thermo Fisher Scientific (1 mentions)
Zetasizer nano zs90, by Malvern Panalytical (1 mentions)
F 2710, by Hitachi (1 mentions)
Dimethyl sulfoxide (dmso), by Bio-Techne (1 mentions)
3 methyladenine 3 ma, by Merck Group (1 mentions)
Mtt solution, by Thermo Fisher Scientific (1 mentions)
10 protocols using ultrospec 7000
1
DPPH Free Radical Scavenging Assay
2
In Vitro CO Release Kinetics
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
In vitro release profile of CO from CORM-2-UDLs was evaluated with a myoglobin assay21 (link),30 (link). Precisely, myoglobin (Mb) solution was prepared by dissolving lyophilized equine heart Mb in phosphate-buffered saline (0.01 mol/L, pH 7.4). Sodium dithionite (0.1%, w/v) was added as a reducing agent to 1 mL of Mb solution to accomplish the conversion of Mb into deoxyMb. CORM-2-UDLs or CORM-2 solution in ethanol (equivalent to 20 μmol/L CORM-2) was then directly mixed with 1 mL of deoxyMb solution in a quartz cuvette. The resultant reaction mixture was covered with 500 μL of light mineral oil to prevent the escape of the released CO and oxygenation of the deoxyMb to Mb. The amount of carbonmonoxy myoglobin (MbCO) produced from the deoxyMb as a result of CO release from CORM-2-UDLs or CORM-2 solution was quantified by measuring the optical density at 510 and 540 nm using a UV–Visible spectrophotometer (Ultrospec 7000, Biochrom Ltd., Cambridge, UK). The produced MbCO was quantified at regular intervals until the release of CO reached a plateau.
3
Characterization of Methotrexate-Loaded Ultradeformable Liposomes
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The physicochemical properties of MTX-UDLs were characterized in terms of particle size, PDI, zeta potential, and entrapment efficiency. The average particle size and PDI of MTX-UDLs were determined by photon correlation spectroscopy using a Zetasizer Nano ZS (Malvern Instruments, Malvern, UK). Prior to measurement, MTX-UDLs were diluted 100 times with filtered deionized water. The zeta potential of MTX-UDLs was measured by electrophoretic light scattering using the same instrument. The entrapment efficiency of MTX-UDLs was determined by ultrafiltration centrifugation method.28 (link) MTX-UDLs were added into Amicon Ultra-0.5 centrifugal filter units (Amicon Ultracel-10k; EMD Millipore, Billerica, MA, USA) and centrifuged at 14,000× g for 30 minutes. The separated vesicles were disrupted by 0.2% Triton X-100 in PBS (pH 7.4). The resultant solution was then analyzed for MTX contents by using UV–visible spectrophotometer (Ultrospec 7000; Biochrom Ltd, Cambridge, UK) at 303 nm. The entrapment efficiency (%) was calculated by using the following equation:
4
Delphinidin Cytotoxicity in A549 Cells
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The A549 cells were seeded into 96-well or 12-well plates at a density of 1 × 104 cells or 1 × 106 cells, and were treated with different concentrations of delphinidin (0–50 µM) for 24 h. For the MTT assay; MTT solution was added to each well, and the plates were incubated for 4 h at 37°C. DMSO was then added to each well, and the plates were incubated for 30 min at room temperature. Cell viability was determined using a spectrophotometer; absorbance was measured at –540 nm (Ultrospec 7000; Biochrom, Holliston, MA, USA). For the Annexin V assay, cells were washed twice in PBS, and were harvested with trypsin-EDTA. Suspended cells were then transferred new tubes, and were incubated for 20 min at room temperature with 100 µl Annexin V reagent. Apoptosis was determined using a Muse Cell Analyzer (Millipore, Billerica, MA, USA).
5
UV Spectrum Analysis of Methanol-Diluted Sample
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The UV spectra was obtained with a Ultrospec 7000 (Biochrom, Holliston, MA, USA) spectrophotometer. The sample was diluted at a 0.3 mg/mL in the MeOH and the absorbance was recorded in the UV/VIS range between 200 to 600 nm.
6
Physicochemical Characterization of Photosensitive Nanoparticles
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Particle size distribution and zeta potential analyses of free Ce6, blank NH2-PEG-PCL nanoparticles (PP), blank G-PEG-PCL nanoparticles (GP), CPP, and CGP were conducted using a Malvern particle size analyzer (Zetasizer Nano ZS-90, Malvern Panalytical). The morphologies of CPP and CGP were visualized through a transmission electron microscope (FEI Talos F200S, Thermo Fisher). The absorption and emission spectra of free Ce6, CPP, and CGP were determined using an ultraviolet‒visible photometer (Ultrospec 7000, Biochrom) and a fluorescence spectrophotometer (F-2710, Hitachi).
7
DPPH Assay for Antioxidant Potency
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
In order to determine the antioxidant potency of the plant samples, a protocol based on the DPPH method and adapted from M. S. Blois 1965 [15 (link)] was used. A 2.10−4 M DPPH solution was prepared using methanol and was then added to different dilution of the plant extracts. The solution was left to react for 30 min and then observed at 517 nm by UV/VIS spectrophotometer (Ultrospec 7000 from Biochrom, Cambridge, UK). The polar plant extract was diluted using HPLC grade methanol and the non-polar extract was diluted using HPLC grade ethyl acetate. The 10−2 and 10−3 dilutions were applied to the plant extracts. A 1:1 (v/v) ratio was applied with the reagent and the plant samples. The positive control both kind of samples was TROLOX (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) 2.10−3 M in methanol and blank was 100% methanol.
8
Determination of TMZ IC50 in C6 Cells
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
In order to determine the half-maximal inhibitory concentration (IC50 value) of TMZ, 5×103 C6 cells in single-cell suspensions were seeded into individual wells of 96-well plates and incubated for 24 h at 37°C prior to treatment with TMZ (0.1, 0.5, 1, 5 or 10 µM; Sigma-Aldrich, St. Louis, MO, USA) diluted in dimethyl sulfoxide (DMSO; Gibco; Thermo Fisher Scientific, Inc.) for 24 h (data not shown). Following determination of the IC50 value of TMZ as 1 mM, cells were treated for 24 h with DMSO alone, 1 mM TMZ, 100 nM VD (Tocris Bioscience, Ellisville, MO, USA) or a combination of the two (1 mM TMZ plus 100 nM VD). To reveal the role of autophagy on C6 cell cytotoxicity, which may be induced by various treatments as mentioned above, cells were treated with 1 mM 3-methyladenine (3-MA; Sigma-Aldrich), an autophagy inhibitor, at 30 min treatments. MTT solution (Thermo Fisher Scientific, Inc.) was added to each well and the plate was incubated for 4 h at 37°C prior to removing the culture medium. DMSO was then added for 30 min at room temperature. Cell viability was determined using a spectrophotometer by measuring the absorbance at 492 nm (Ultrospec 7000; Biochrom, Holliston, MA, USA). Viability for each group was calculated as a percentage of that of the control group.
9
Polyphenol Oxidase and Peroxidase Activity Assay
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The polyphenol oxidase (PPO) activity was determined according to the method reported by Yi et al. [19 (link)] with slight modifications. Each 1 mL juice was mixed with 2 mL substrate containing 0.07 M catechol and 0.2 M phosphate buffer (pH 6.5) as the enzymatic reaction solution.
The peroxidase (POD) activity was determined based on the method reported by Cao et al. [20 (link)] with slight modifications. Each 1 mL juice was diluted by 1–5 times and then mixed with 2 mL 1.0% (v/v) guaiacol (0.2 M, pH 6.5 phosphate buffer) and 0.2 mL 1.5% hydrogen peroxide as the enzymatic reaction solution.
The absorbance at 420 nm and 470 nm of PPO and POD enzymatic reaction solutions were immediately recorded by a spectrophotometer (Ultrospec 7000, Biochrom LTD, Cambridge, UK) at intervals of 2 s for 4 min. The specific activities of PPO and POD (Abs/min) were calculated according to the slopes of the linear portion of reaction curves, and the residual activities of enzymes were calculated according to Equation (3):
where At and A0represent the specific activities of treated and untreated samples.
The peroxidase (POD) activity was determined based on the method reported by Cao et al. [20 (link)] with slight modifications. Each 1 mL juice was diluted by 1–5 times and then mixed with 2 mL 1.0% (v/v) guaiacol (0.2 M, pH 6.5 phosphate buffer) and 0.2 mL 1.5% hydrogen peroxide as the enzymatic reaction solution.
The absorbance at 420 nm and 470 nm of PPO and POD enzymatic reaction solutions were immediately recorded by a spectrophotometer (Ultrospec 7000, Biochrom LTD, Cambridge, UK) at intervals of 2 s for 4 min. The specific activities of PPO and POD (Abs/min) were calculated according to the slopes of the linear portion of reaction curves, and the residual activities of enzymes were calculated according to Equation (3):
where At and A0represent the specific activities of treated and untreated samples.
10
Quantifying Chlorophyll in Wildtype and Mutant Plants
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The total chlorophyll contents in the first leaf of 20-d-old wildtype and taare1 mutant lines under different hydroponic culture solutions were measured according to a published protocol (Lichtenthaler, 1987) . Chlorophyll was extracted with 100% ice-cold acetone and the chlorophyll content was calculated spectrophotometrically based on the absorbance of the supernatant at 644.8 nm and 661.6 nm. Samples were diluted to an optimal concentration before measuring using a spectrophotometer (Ultrospec 7000; Biochrom).
About PubCompare
Our mission is to provide scientists with the largest repository of trustworthy protocols and intelligent analytical tools, thereby offering them extensive information to design robust protocols aimed at minimizing the risk of failures.
We believe that the most crucial aspect is to grant scientists access to a wide range of reliable sources and new useful tools that surpass human capabilities.
However, we trust in allowing scientists to determine how to construct their own protocols based on this information, as they are the experts in their field.
Ready to get started?
Sign up for free.
Registration takes 20 seconds.
Available from any computer
No download required
Revolutionizing how scientists
search and build protocols!