How does DPPH radical scavenging activity work?

DPPH free radical scavenging is an accepted mechanism for screening the antioxidant activity of plant extracts. In the DPPH assay, violet color DPPH solution is reduced to yellow colored product, diphenylpicryl hydrazine, by the addition of the extract in a concentration dependent manner.

What is the role of DPPH in antioxidant activity?

The DPPH assay is used to predict antioxidant activities by mechanism in which antioxidants act to inhibit lipid oxidation, so scavenging of DPPH radical and therefore determinate free radical scavenging capacity. The method is widely used due to relatively short time required for the analysis.

Why methanol is used in DPPH assay?

The standard DPPH assay uses methanol or ethanol as solvents, or buffered alcoholic solutions in a ratio of 40%/60% (buffer/alcohol, v/v) to keep the hydrophobic hydrazyl radical and phenolic test compounds soluble while offering sufficient buffering capacity at different pHs tested.

What is DPPH inhibition?

2, 2–diphenyl–1–picrylhydrazyl (DPPH) inhibition was used to evaluate the antioxidant activity of CPS. Response surface methodology (RSM) was used to investigate the effects of PEF treatment parameters on antioxidant activity of CPS.

What is the absorbance of control in DPPH?

DPPH is a stable free radical in a methanolic solution. In its oxidized form, the DPPH radical has an absorbance maximum centered at about 520 nm (Molyneux, 2004).

Why is DPPH kept in the dark?

With reference to the dark, the DPPH solution utilized, demands darkness, as light would oxidize further the DPPH radical with the solution to be determined interfering with your results. So, stay close with the protocol and proceed by the book.

What is the absorbance of DPPH?

Why DPPH is used in antioxidant assay?

DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical method is an antioxidant assay based on electron-transfer that produces a violet solution in ethanol (10). This free radical, stable at room temperature, is reduced in the presence of an antioxidant molecule, giving rise to colorless ethanol solution.

What is control in DPPH assay?

For DPPH assay methanol is used as blank where as DPPH + methanol is used as experimental control.

Why is DPPH stable?

The molecule of 1,1-diphenyl-2-picryl- hydrazyl (α,α-diphenyl-β-picrylhydrazyl; DPPH: 1) is characterised as a stable free radical by virtue of the delocalisation of the spare electron over the molecule as a whole, so that the molecules do not dimerise, as would be the case with most other free radicals.

What is a good IC50 value in DPPH assay?

The IC50 values were 63.69 μg/mL for Trolox and 41.25 μg/mL for ascorbic acid in the DPPH method, 42.11 μg/mL and 28.23 μg/ mL in the the ABTS method, and 54.61 μg/mL and 39.25 μg/mL in the the OH method, respec- tively. The DPPH radical-scavenging capacity of the analyzed samples is shown in Table 2.

How do you make a 0.1 mM DPPH?

1 M of DPPH = 394.32 gram of DPPH in 1 liter of solution (make the volume up to 1-liter level after dissolving the DPPH in less volume of methanol). 1 mM of DPPH must contain 0.394 grams in a 1-liter solution. 0.1 mM DPPH must contain 0.0394 gram of DPPH in 1 liter of solution.

Why ascorbic acid is used in DPPH assay?

Ascorbic acid is used as standard because of its availability in different food sources (especially citrus fruit extracts).

What is IC50 in DPPH?

The IC50 value is a parameter widely used to measure the antioxidant activity of test samples. It is calculated as the concentration of antioxidants needed to decrease the initial DPPH concentration by 50% [23]. Thus, the lower IC50 value the higher antioxidant activity.

How is IC50 calculated in DPPH assay?

you can calculate the IC50 as follows: IC50 = (0.5 – b)/a. You replace (y) by 50 in the equation y = 1.3534 x + 0.58 and you deduce ( x) .

What is the molar mass of DPPH?

394.32 g/molDPPH / Molar mass

What is IC50 value in DPPH assay?

Why DPPH radical is stable?

What is the DPPH assay?

The DPPH assay is a typical off-line detection method, where the antioxidant activity is measured colorimetrically.

What is the DPPH radical scavenging assay?

Henceforth, this compound usually used in DPPH assay for the determination of antioxidant activity of medicinal plants, fruits or any other biological substrates. Zheng Chen et al. have used the DPPH radical scavenging assay according to the method reported by Brand-Williams et al. (1995), with some modifications.

Why is the DPPH method widely used in organic chemistry?

The method is widely used due to relatively short time required for the analysis. The DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical is very stable, reacts with compounds that can donate hydrogen atoms, and has a UV–vis absorption maximum at 515 nm.

Does DPPH absorbance change with the addition of test materials?

In the presence of compounds that are capable of either transferring an electron or donating hydrogen, the DPPH will become discolored. In the literature, the change in DPPH absorbance after the addition of a test material is often used as an index of the antioxidant capacity of the material ( 107 ).