Total Phenolic Content (TPC) Calculation in Microsoft Excel | Step-by-Step Beginner Tutorial

How to calculate total phenolic content:
1) Plot the standard calibration curve:
- plot absorbance vs standard concentration (10-100 ug/mL)
- obtain the equation y=mx+c
- ensure R2 is more than 0.95
y=absorbance, x=concentration, m=slope, c=intercept
2) Calculate the concentration of phenolic content in samples using the equation y=mx+c
- rearrange equation; x=(y-c)/m
- x is the concentration of phenolic content in ug/mL
- convert ug/mL to mg/mL if necessary
3) Calculate the total phenolic content (TPC)
- TPC = cv/m
c=concentration of phenolic content
v=volume of methanolic extract solution used
m=weight of extract per mL in gram unit

[@esraesmio7153]

Thank you for the AMAZING VIDEO!! If you don’t mind I need to article that is utilized for this protocol!

[@alemlaimchen9089]

Thank you for such an elaborate video. really helpful. I want to confirm if I want the TPC (A) unit in mg GAE/100g extract then do I just multiply by 100??

[@NaturalProductThings]

You're welcome :) yes, that is true. Multiply the TPC value by 100 to get the amount per 100g of extract. eg: TPC (mg GAE/g extract) × 100 = TPC (mg GAE/100g extract) 112 mg GAE/g extract × 100 = 11,200 mg GAE/100g extract

[@ruchicsurya8282]

Thank u thank u so much last minute saviour❤

[@NaturalProductThings]

Glad it helped!

[@sugarplums74]

thank you so much!! your content really help me 🥺🥺 may you always have a good dayy

[@NaturalProductThings]

you're welcome ! all the best for your studies :)

[@Matladi474]

Thank you for the nice presentation. is it possible to get negative values for total phenolic content?

[@NaturalProductThings]

No, it's not possible to get negative values for total phenolic content. The total phenolic content measures the amount of phenolic compounds in a sample, which is always a positive number because you can't have less than zero of these compounds. If you see a negative value, it might be due to an error in the measurement process or data entry. Potential reasons for obtaining negative values: 1. Blank Subtraction Errors: -Incorrect subtraction of the blank sample can lead to negative values. -Ensure the blank is properly prepared and its absorbance is correctly subtracted from the sample readings. 2. Calibration Curve Issues: -Errors in preparing or using the calibration curve can lead to incorrect TPC values. Verify that the calibration curve is correctly plotted, and the equation used to calculate the TPC is accurate. -Ensure the standard solutions for the calibration curve are prepared correctly and their absorbances fall within the linear range of the curve. 3. Sample Preparation Errors: -Inaccurate dilution or errors in sample preparation can affect the results. Double-check the volumes and concentrations used in the assay. -Ensure that the samples are homogenized properly and that no particulate matter could scatter light and affect absorbance readings. 4. Reagent Issues: -Degradation or contamination of reagents can lead to erroneous results. Verify the quality and expiration dates of the reagents used in the assay. -Ensure the reagents are prepared fresh and stored under appropriate conditions.

[@jiata1]

Pleae are you familiar with the Bradford assay for determining protein concentration? Thank you very much

[@NaturalProductThings]

Sorry I'm not really familiar with that assay

[@IsmailELBZAR]

thank you please i have a question. i used this protocol in my experiment: Approximately 0.2 g of F. vulgaris roots or leaves per treatment were homogenized in 95% methanol. The homogenate was centrifuged at 30,000× g for 10 min. 1 mL aliquots of the extracts were mixed with 1 mL of 1 N Folin-Ciocalteau reagent and 1 mL of 10% sodium carbonate, and the mixture was incubated for 1 h at 35 °C. The absorbance was measured at 530 nm and total phenol content was expressed as gallic acid equivalents in milligrams per gram of dry matter. my question how convert mg per ml to mg per g.

[@NaturalProductThings]

Do you mean how I got the weight of the dry extract? Watch at 2:53 to see how I calculate the weight of the extract in g. 1. You need to know the concentration of the extract used for the reaction. 2. For example, I used 0.1 mg/mL (concentration) of the extract, which means 0.1 mg of the extract was dissolved in 1 mL of methanol. So, the mass of the extract here is 0.1 mg. Convert 0.1 mg to g, which means the weight of the extract used to determine the TPC per 1 mL is 0.0001 g. 3. The volume of the extract used doesn't matter to find the dry sample's weight because the part where you need the volume is 'v' as in the formula. I hope I'm answering your question.