It is quite simple, let me clarify you,

Just follow your calibration curve (is it in ug of gallic acid/mL), if so "x" would give you the microgram of gallic acid equivalent per ml of your solution, now multiply this with 50 (this give you microgram of TPC/5mg of your plant extract. Now just see an appropriate unit (may be mg/g of extract or ug/g of extract or others), One more thing if you want to express your result per gram of plant powder the above answer with yield and divide by amount of plant material processed. Best of luck.

for further consultation

DOI: 10.1007/s13197-014-1562-9

Dear Sir. Concerning your issue about the calculation for the determination of the total phenolic content (TPC) in Plant Extract.

First you need to use equation y=0.0109x- 0.022 to calculate the value of x

Where y = Absorbance

x = concentration from the calibration curve

This implies that x = 0.541 + 0.022/0.0109

x = 51.65 mg/mL

Therefore, TPC can be calculated as follows

TPC = cV/m

Where c= concentration from calibration curve

V= Volume of the extract used

m= Mass of the extract used

Therefore, TPC = cV/m

TPC = 51.65x50/5.0

TPC = 516.5 mg /g

May I know the type of standard and its concentration. I think the following below links may help you in your analysis:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.877.487&rep=rep1&type=pdf

http://www.sciencedirect.com/science/article/pii/S1658365514001046

http://www.sphinxsai.com/Oct_dec_2010_vol2_no.4/PharmTech_vol2_no.4_1_pdf/PT=40%20(2403-2406).pdf

Thanks



I use Gallic acid(5mg/50ml) as standard.

Thnansk.

Dear Hammad Saleem

So according to the mentioned above the answer should be:

TPC = 516.5 mgGAE/g

Regards,

Dear Hammad Salem and Isam Eldin

Let me clarify one more thing you cannot estimate phenolic content following a single concentration of gallic acid as you are discussing here. In fact you have plotted a calibration curve so the unit of "X" would be as same as were present on the x-axis it may be mg/mL or ug/mL so having clear understanding is more important for correct calculation. Otherwise like many people do you may get 1025 mg GAE/g (A none sense) in an other sample. may be you have already faced same. I just mean to say double check and follow you calibration curve