How can I calculate IC50 in DPPH test?

Can two EC50 values with different hill slopes be compared?

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23 February 2021 8,155 5 View

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Why do the absorbance values of different concentrations of ascorbic acid solutions mixed with DPPH free radicals stay constant?

26 January 2021 458 14 View

Can anyone help to find any research articles related to the below mentioned objective?

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25 January 2021 9,399 4 View

How could i explain the EC50 data utilized by graph Pad prism 9 ?

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17 January 2021 4,576 3 View

IC50 value from this graph?

01 January 2021 6,848 4 View

I am performing enzyme inhibition assay and the substrate is fluorogenic & fluorescence was measured. Now I want to calculate Vo and Vi. How can I ??

These are the per minute fluorescence observed. Please guide me how can I determine Vi, Vo and IC50 ? By slope determination or any other method? Control: 28.11 40.30 40.78 37.61...

11 December 2020 1,037 4 View

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Anyone familiar with antioxidant studies on rats' brain homogenate?

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Mohamed Sabri Bensaad

Dear Dr Rufayda Izzeldin,

Here's the method:

If you use are using GraphPad prism:

From the data table, click Analyze, choose nonlinear regression, and choose the panel of equations: Dose-Response -- Special, X is log(concentration). Then choose "Absolute IC50, X is log(concentration)". You must enter a value for the parameter "Baseline" on the Constrain tab of the analysis parameters dialog.

If you are using Excell:

insert a "scatter plot," and set the Y-axis to "logarithmic." It should be approximately linear over some range. Select "add trend line" and pick "exponential." Then display equation and you've got it.

Best wishes,

Sabri

Naveen Dhingra

Plot a scatter plot graph at different concentration in excel and and fit the data with a straight line and calculate the value with y=m*x+c where y= % scavenging and x= concentration. Use y=50 and identify the concentration.

Imen Laib

The simplest estimate of IC50 is to plot x(concentration of extract),y (inhibition of DPPH (%)and fit the data with a straight line (linear regression). IC50 value is then estimated using the fitted line, i.e., Y = a * X + b, IC50 = (50 - b)/a.

Kang Thierry Roland

To calculate IC50 of DPPH, you can use graphpad prism. You will plot a dose-response curve with Log(conc) on x-axis and anti-oxidant activity of DPPH on the y-axis. Graphpad prism will give you the IC50 value together with other parameters.

Ifeoma Felicia Chukwuma

IC 50 of DPPH could be calculated from slope of scatter plot in excel. But using non-regression plot in Graph Pad prism is much easier. it also give graph which you can also include in your manuscript.

Please, check this article out

Hanim Abdelhalim

select concentrations inhibit lower and higher than50% of the radical

Insert them in excel and choose a scatter plot graph and fit the data with a straight line and calculate the value from the given equation. Where y=50 and calculate the concentration

Harto Widodo

by making linear regression of the series concentration of DPPH (x-axis) and the percentage inhibitions (y-axis) which will be calculated by excel or other statistical software as Y= aX + c, for example, Y = 0.3782x + 3.1812. Then change the Y value by 50 and calculate the x value, which is 123.79. The IC50 of the DPPH is x value i.e. concentration of DPPH which is 123.79 ug/ml. The unit (ug/ml) depends on your own experiment.

Yamin Taeri

Please, you make a linear regression between the concentration (x) and the percentage of inhibition, so that the regression equation y = bx + a is obtained. Then y is replaced with the value 50. so it will be 50 = bx + a, and x = (y-a)/b. and the x value obtained is the IC50 value.

Thank you