Free Radical Dpph
Experiments were carried out according to the literature with some modifications [18]. Briefly, 200 µL of extract solution with different concentrations (1.953-1000 µg/mL) was loaded in 96-well plate. DPPH in absolute methanol (50 µL, 1 mM) was added into wells. The reaction mixture was shaken well and incubated for 30 min at room temperature in the dark. The absorbance of the resulting solution was recorded at 517 nm. The test was performed in triplicate. The percentage inhibition of DPPH was calculated according to the following Equation 1:
IC (%) = (A0-At)/A0 x 100 (1) where, IC (%) is a inhibition percentage of DPPH radical. A0 is the absorbance of a blank that was prepared in the same conditions, but without sample, and At is the absorbance of test samples. Ascorbic acid was used as a positive control. A lower IC50 value indicates greater antioxidant activity.
2.4.2. β-Carotene-linoleic Acid Bleaching
…show more content…
A stock solution of β-carotene-linoleic acid was prepared by mixing 1 mL of chloroform with 0.5 mg β-carotene, 25 μL linoleic acid and 200 mg tween 40 into round bottom flask. The mixture was then evaporated at 40°C for 10 min by rotary evaporator to remove chloroform and immediately diluted with 100 mL of distilled water. The water was added to the mixture with vigorous shaking to form an emulsion. Then, 2.5 mL emulsion and 350 μL extacts (1 mg/mL) were added. The system was incubated in hot water bath at 45°C for 1 hour. The absorbance of the samples, standard and control was measured at 470 nm using a Thermo Scientific™ Multiskan™ GO Microplate Spectrophotometer against a blank, consisting of an emulsion without β-carotene. The measurement was carried out at initial time (t = 0) and successively at 15 min intervals for 120 min. All samples were assayed in triplicate. The inhibition percentage (I %) of the samples was calculated using following Equation 2:
I (%) = (A1/A0) x 100 (2) where, A1 is the absorbance of β-carotene after 1 h assay remaining in the samples and A0 is the absorbance of β-carotene at beginning of the experiments. Ascorbic acid was used as a positive control. A higher I% value indicates greater antioxidant activity.
2.5. Statistical Analyses
All experiments were carried out in triplicates
Unknown Compounds
469 Words | 2 PagesMore specifically, this lab was met in terms of gaining an understanding in separating an acid, base and neutral compound from a mixture and identify through melting point. Overall, the experiment was successful as the acid (benzoic), base (5-chloro-2- methoxyaniline) and neutral (biphenyl) compounds were correctly identified. The separation of mixtures compounds to give pure components is of great importance in chemistry and in specific in organic chemistry. Many synthetic reactions give mixtures of products and it is important to isolate the wanted compound with a precise methodology of extraction and purification. Identification of the compound can always be identified by melting point
Horseradish Peroxidase Lab Report
1090 Words | 5 PagesABSTRACT To catalyze a reaction, an enzyme will grab on (bind) to one or more reactant molecules. In this experiment we examined how increasing the volume of the extract added to the reaction would affect the rate of the reaction. The enzyme used was horseradish peroxidase which helps catalyze hydrogen peroxide. Using different pH levels, the absorbance rate of the reaction was measured to see at which condition the enzyme worked best. The rates of absorption were calculated using a spectrophotometer in 20 second intervals up to 120 seconds.
Hydrolysis Of T-Butyl Chloride Lab Report
1766 Words | 8 PagesIn addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
Two Components Of An Unknown Mixture Lab Report
760 Words | 4 PagesThe purpose of this experiment was to identify the two components of an unknown mixture through diverse experimental techniques such as recrystallization, extraction, melting point, and acid-base reactions. From this, the group to which these two compounds belong to had to be determined. These groups are: Carboxylic Acids, phenols, and neutrals. By determining the melting points of the two unknown compounds, these values were compared to the values of melting points in the chart and the proper compound was selected. For the case of this experiment, the unknown mixture contained, 4-methylbenzoic acid.
Thin Layer Chromatography Lab Report
159 Words | 1 PagesThe molecular formula is a way to tell if a structure is polar or not. Thin layer chromatography was used to see the polarity of components in a mixture. The silica gel on the TLC plate and the mixture can tell the relative Rf or Rf of the different spots on the plate. On the TLC plate, the order was β-carotene, pheophytin a or b, chlorophyll a, chlorophyll b, and then lutein. The relative Rf for β-carotene was closer to one compared to the other pigments, so β-carotene was more polar then the rest of the pigments.
Binary Liquid Vapour Phase Diagration Lab Report
1855 Words | 8 PagesThe sample was placed into appropriate vials as the liquid (L), and the vial was closed by the stopper. For 59.0℃ (acetone-rich side of azeotrope). 25 mL of chloroform and 75 mL acetone were added into the 250 mL round bottom flask. Small amount of boiling stone was added into the flask.
Orange Juice Vs Electrolytes Essay
743 Words | 3 PagesIn recent research studies, the healing properties of oranges have been associated with a wide variety of phytonutrient compounds. these phytonutrients include citrus flavanones when it's combined with vitamin c the antioxidant properties are expected to be there but it's another molecule that makes the vitamin c stronges and it is the hesperidin molecule which has been singled out as the most important
Lycopene Lab Report
400 Words | 2 PagesIntroduction Carotenoids are pigments that are found mainly in chloroplasts of plants and in some photosynthetic organisms. They are synthesised naturally in plants in order to absorb light during photosynthesis and protect plants against photosensitization. They are found in our diet, through eating fruit and vegetables and many serve as an important source of vitamin A in our diets, such as ß-carotene. The structure of the molecule determines the colour, photochemical properties, vitamin activity and its chemical reactivity on oxidising agents and free radicals.
Deoxyribose Lab
2057 Words | 9 PagesThe reagents used were Diphenylamine reagent which contains concentrated H2SO4. The standard solution used for this test is the deoxyribose standard solution. In the sample, only a faint blue solution appeared, which indicates a small presence of deoxyribose. In test for Phosphate, the standard solution was the Phosphate solution and the reagents used were concentrated H2SO4, concentrated HNO3, 2.5% ammonium molybdate solution.
Organic Modifier Case Study
1433 Words | 6 Pages3. Results and discussion 3.1. Optimization of chromatographic conditions A rapid, simple, reproducible and accurate RP-HPLC method was developed for simultaneous determination of pregabalin and atenolol in dosage forms, spiked and volunteer human urine.
Effect Of Enzyme Concentration On Enzyme Reaction
1046 Words | 5 PagesThe 3 concentrations of enzymes were 0.5 ml, 1.0 ml, and 2.0 ml of turnip extract, while the substrate consisted of 0.1ml, 0.2 ml, and 0.4 ml of hydrogen peroxide. In a separate tube, the control was made up of turnip extract and guaiacol, known as the color reagent. This was recorded the absorbance every 20 seconds for 3 minutes.
Fatty Acid Methyl Ester Mix (DPPH)
1359 Words | 6 PagesThe microplate was automatically shaken prior each reading. A blank using phosphate buffer instead of the fluorescein and eight calibration solutions using Trolox (1-8 µM, final concentration) as antioxidant were also carried out in each assay. All the reaction mixtures were prepared in duplicate, and at least three independent assays were performed for each
Column Chromatography Lab Report
1696 Words | 7 PagesThis experiment aims to separate the components of the green colored food dye and get the TLC profile of each eluent collected. III. Experimental Procedure Before starting with the column chromatography for food dye, the right solvent must be chosen between 2-butanol with acetic acid, ammonia in butanol, 1 part 1-butanol 1 part acetic acid, and 2 parts methanol 1 part water. In choosing the appropriate solvent for column chromatography, the solvent system must give a TLC profile wherein most of the spots are well separated and has a Rf value within 0.3-0.5.
Free Radical Inorganics
936 Words | 4 PagesAn oxidation process is always accompanied by a reduction process in which there is usually a loss of oxygen, while in an oxidation process there is a gain in oxygen (Hrbac J, Kohen R, 2000). Such reactions, called redox reactions, are the base for numerous biochemical pathways and cellular chemistry, biosynthesis, and regulation (ShapiroM, 1972). They are also important for understanding biological oxidation and radical/antioxidant effects. While reductant and oxidant are chemical terms, in biological environments they should be termed antioxidant and pro-oxidant, respectively (Cao G, Prior RL,
Hydroxy Acetophenene Lab Report
754 Words | 4 Pages4.1 General Remarks: Most of the reactions were carried out in oven dried glass wares with magnetic stirrer and and reflux condenser using freshly solvents. Reactions are monitored on aluminium coated thin layer chromatography (TLC) with UV light and iodine as developing agents. Melting points were determined on melting point apparatus. Proton magnetic spectra were recorded on Brucker 400MHz spectrometers using tetramethylsilane (TMS) as internal standard. Chemical shifts has been expressed in δ values downfield from TMS, multiplicity of NMR signal is designated as s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet).Infrared spectra were recorded on Agilent Technologies FT-IR spectrophotometer.
More about Free Radical Dpph
Unknown Compounds
469 Words | 2 PagesHorseradish Peroxidase Lab Report
1090 Words | 5 PagesHydrolysis Of T-Butyl Chloride Lab Report
1766 Words | 8 PagesTwo Components Of An Unknown Mixture Lab Report
760 Words | 4 PagesThin Layer Chromatography Lab Report
159 Words | 1 PagesBinary Liquid Vapour Phase Diagration Lab Report
1855 Words | 8 PagesOrange Juice Vs Electrolytes Essay
743 Words | 3 PagesLycopene Lab Report
400 Words | 2 PagesDeoxyribose Lab
2057 Words | 9 PagesOrganic Modifier Case Study
1433 Words | 6 PagesEffect Of Enzyme Concentration On Enzyme Reaction
1046 Words | 5 PagesFatty Acid Methyl Ester Mix (DPPH)
1359 Words | 6 PagesColumn Chromatography Lab Report
1696 Words | 7 PagesFree Radical Inorganics
936 Words | 4 PagesHydroxy Acetophenene Lab Report
754 Words | 4 Pages